An Investigation in the Comparability of the Exposure and Recommended Dose of Selected Pfizer Drugs in East Asian Countries: Is Mutual Usage of Clinical Data Among East Asian Countries Feasible?

The current regulatory path for new drug registration in East Asian countries has led to significant delay of the new medicines in these countries. A unified regulatory path and allowance of mutual usage of clinical data in East Asian countries would lead to cost saving in drug development and expedite the new drug registration in these countries. The objectives of the present analysis are to compare the approval dates of a selection of products developed by Pfizer in the United States and East Asian countries (China, Japan, Korea) and compare the pharmacokinetics and recommended doses of these products in East Asian countries. Eighteen products (20 drugs, 2 products with 2 combination drugs) with exposure data available in at least 2 of the 3 East Asian countries across different therapeutic areas were included in the analyses. The results showed that most products had delayed approval in East Asian countries (up to 8 years) after US or EU approval. No distinct differences were observed in the drug exposure and recommended doses for the selected products in East Asian countries. These results together with literature data of genetic similarity of the East Asian populations support the mutual usage of the clinical data in the East Asian countries for expedited regulatory submission and approval.

A comprehensive update on the ADMET considerations for α2δ calcium channel ligand medications for treating restless legs syndrome

INTRODUCTION

Restless legs syndrome/Willis-Ekbom disease (RLS/WED) is a sleep-related sensory-motor disorder associated with poor sleep quality and impaired daily functioning. In patients affected by chronic RLS/WED, a pharmacological therapy is recommended. International guidelines suggest to start the treatment with a α2δ calcium channel ligand in most cases, unless contraindicated.

AREAS COVERED

The present review is based on an extensive Internet and PubMed search from 1986 to 2024. Our purpose is to describe the absorption, distribution, metabolism, and toxicology (ADMET) of the α2δ ligands, with common consideration for the therapeutic class, specificities of different compounds, efficacy, and safety in relation to other treatment options.

EXPERT OPINION

α2δ ligands are quite similar in their ADMET profiles, sharing most of the pharmacokinetics and potential adverse effects. However, we highlight the linear kinetic of gabapentin enacarbil and pregabalin, differently from gabapentin. α2δ ligands are safe and effective for the treatment of RLS/WED. Additional benefits can be obtained in comorbid insomnia, chronic pain syndromes, history of impulse control disorder, and comorbid anxiety. The use of α2δ ligands is associated with poor risk of augmentation. We still need new long-term safe and effective treatments, which could be developed along with our knowledge of RLS/WED pathophysiology.

Pharmacokinetic properties of a new sustained-release pregabalin tablet in subjects with reduced renal function

A new sustained-release (SR) pregabalin tablet, YHD1119, was formulated for once-daily dosing. In the current study, we aimed to evaluate the pharmacokinetics of YHD1119 tablets in patients with reduced renal function. Subjects were grouped by creatinine clearance: > 60 mL/min/1.73m2 (Cohort A) and 30-60 mL/min/1.73m2 (Cohort B). Eight subjects in Cohort A received a YHD1119 75 mg tablet (Y75T) and a YHD1119 150 mg tablet (Y150T) in each period, and eight subjects in Cohort B received a Y75T. Non-compartment analysis and population pharmacokinetic analysis using a one-compartment model with first-order elimination and first-order absorption with lag time were performed. Sixteen subjects completed the study. The geometric mean ratio (GMR) (90% confidence intervals [CI]) for maximum concentration (Cmax), and area under the concentration-time profile from 0 to the last measurable time (AUClast) after Y75T of Cohort B to those of Y75T of Cohort A were 1.2273 (1.0245-1.4701), and 2.4146 (1.8142-3.2138), respectively. The GMR (90% CI) for Cmax, and AUClast after Y75T of Cohort B to those of Y150T of Cohort A were 0.6476 (0.5229-0.8021), and 1.1471 (0.8418-1.5632), respectively. Simulated steady-steady pregabalin concentrations after once-daily Y75T dosing in subjects with eGFR 45 mL/min/1.73 m2 were within the range of steady-state concentrations simulated after once-daily Y150T dosing in subjects with eGFR 90 mL/min/1.73 m2. The total pregabalin exposure of Y75T in patients with moderate renal impairment was comparable with that of Y150T in subjects with near-normal renal function.

Trial Registration

ClinicalTrials.gov Identifier: NCT05012436.

Evaluating the Effect of Pregabalin in the Treatment of Carpal Tunnel Syndrome: A Prospective, Randomized, Triple-Blinded, Placebo-controlled Trial

OBJECTIVE

This study aimed to determine the effectiveness of pregabalin for the control of symptoms in mild to moderate idiopathic Carpal tunnel syndrome (CTS).

METHODS

In this randomized, placebo-controlled trial, 146 mild to moderate idiopathic CTS patients were randomized into pregabalin (n=74) and placebo groups (n=72). Per protocol, analysis was conducted with 131 patients; pregabalin (n=65) and placebo (n=66). The drug titration dose was 50 mg once daily for the first week, twice daily for the second week and thrice daily for the next 6 weeks. The primary outcome included a change in the Symptom Severity Scale and Functional Status Scale (FSS) of the Boston Carpal Tunnel Questionnaire after the eighth week. The secondary outcome was the change in clinical and electrophysiological grading after 8 weeks of therapy.

RESULTS

There was a statistically significant improvement in the mean Symptom Severity Scale (14.92±3.72 vs. 16.55±4.45; P =0.025) and FSS (10.77±2.64 vs. 12.0±2.55; P =0.007) in the pregabalin group after 8 weeks. Mean clinical and electrophysiological grading changed significantly from 2.3±0.7 to 2.1±0.8 ( P =0.001) and 1.9±0.7 to 1.8±0.8 ( P =0.020), respectively in the pregabalin group but not in the placebo group.

DISCUSSION

The results of this study demonstrates that pregabalin is effective in ameliorating symptoms and improving functional outcomes in mild to moderate idiopathic CTS.

The effect of pregabalin on postoperative pain after anterior cruciate ligament reconstruction: A systematic review of randomized clinical trials

Background

Despite the enormous success of anterior cruciate ligament (ACL) reconstruction, acute neuropathic pain can develop postoperatively and is both distressing and difficult to treat once established. Pregabalin, an anticonvulsant agent that selectively affects the nociceptive process, has been used as a pain relief agent. The purpose of this systematic review of randomized controlled trials (RCTs) was to evaluate the pain control effect of pregabalin versus placebo after ACL reconstruction.

Method

A search of the literature was performed from inception to June 2022, using PubMed, Scopus, Google Scholar, Web of Science, Cochrane and EBSCO. Studies considered for inclusion were RCTs that reported relevant outcomes (postoperative pain scores, cumulative opioid consumption, adverse events) following administration of pregabalin in patients undergoing ACL reconstruction.

Result

Five placebo-controlled RCTs involving 272 participants met the inclusion criteria. 75 mg and 150 mg oral pregabalin was used in included trials. Two studies used a single dose of pregabalin one hour before anesthesia induction. Two studies used pregabalin 1 hour before anesthesia induction and 12 hours after. One study used daily pregabalin 7 days before and 7 days after surgery. Out of five papers, three papers found significantly lower pain intensity and cumulative opioid consumption in pregabalin group compared with placebo group. However, a decrease in pain scores was found in all trials. Pregabalin administration was associated with dizziness and nausea.

Conclusion

The use of pregabalin may be a valuable asset in pain management after ACL reconstruction. However, future studies with larger sample size and longer follow-up period are required.

Application of gabapentinoids and novel compounds for the treatment of benzodiazepine dependence: the glutamatergic model

BACKGROUND

Current approaches for managing benzodiazepine (BZD) withdrawal symptoms are daunting for clinicians and patients, warranting novel treatment and management strategies. This review discusses the pharmacodynamic properties of BZDs, gabapentinoids (GBPs), endozepines, and novel GABAergic compounds associated with potential clinical benefits for BZD-dependent patients. The objective of this study was to review the complex neuromolecular changes occurring within the GABAergic and glutamatergic systems during the BZD tolerance and withdrawal periods while also examining the mechanism by which GBPs and alternative pharmacological therapies may attenuate withdrawal symptoms.

METHODS AND RESULTS

An elaborative literature review was conducted using multiple platforms, including the National Center for Biotechnology (NCBI), AccessMedicine, ScienceDirect, pharmacology textbooks, clinical trial data, case reports, and PubChem. Our literature analysis revealed that many distinctive neuroadaptive mechanisms are involved in the GABAergic and glutamatergic systems during BZD tolerance and withdrawal. Based on this data, we hypothesize that GBPs may attenuate the overactive glutamatergic system during the withdrawal phase by an indirect presynaptic glutamatergic mechanism dependent on the α₂δ₁ subunit expression.

CONCLUSIONS

GBPs may benefit individuals undergoing BZD withdrawal, given that the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor current significantly increases during abrupt BZD withdrawal in animal studies. This may be a conceivable explanation for the effectiveness of GBPs in treating both alcohol withdrawal symptoms and BZD withdrawal symptoms in some recent studies. Finally, natural and synthetic GABAergic compounds with unique pharmacodynamic properties were found to exert potential clinical benefits as BZD substitutes in animal studies, though human studies are lacking.

Pregabalin Alleviates Anxiety and Fear in Cats during Transportation and Veterinary Visits-A Clinical Field Study

Cats frequently suffer from anxiety related to travel and veterinary visits. One sequela is avoidance of veterinary visits and lack of adequate veterinary care. The objective of this study was to test clinical efficacy and safety of a novel formulation of a pregabalin 50 mg/mL oral solution for alleviation of anxiety and fear in cats during transport and veterinary visits. A total of 209 client-owned cats were given either a flavored pregabalin oral solution at the dosage of 5 mg/kg (n = 108) or an identical placebo (n = 101) approximately 90 min before placing them into the carrier and transporting them in a car for at least 20 min to a veterinary clinic. The treatment effect using a 5-point numerical rating scale was evaluated during transportation by the owner and during clinical examination by the veterinarian, both blinded to the treatment. In addition, to verify the owner assessment, an external expert blinded to the treatment and owner assessment evaluated the transportation video recordings using the same rating scale as the owner. Pregabalin 5 mg/kg statistically significantly decreased both travel- (p < 0.01) and veterinary-visit- (p < 0.01) related anxiety compared to the placebo. The external expert's evaluation was in agreement with the owners' assessment confirming the treatment effect during transportation (p < 0.01). Treatment was well tolerated with only a few cats showing transient slight incoordination and tiredness. The flavored oral solution formulation with a small dosing volume of 0.1 mL/kg was found by the owners to be user-friendly and was well-accepted by the cats. This study demonstrated that a single oral dosage of the novel pregabalin oral solution alleviates anxiety and fear related to transportation and veterinary visits in cats, thus providing practical aid for both owners and veterinarians to enable cat-friendly handling and improving the welfare of cats in situations they often perceive as very stressful.

The Effect of Pregabalin Levels on Pain and Substance P Level Post-Cesarean Section

BACKGROUND: Post-operative pain is a very important problem faced by post-operative patients. Antihyperalgesia is caused by the inhibition of the neurotransmitter glutamate and substance P (SP) by pregabalin. This study aimed to compare the effect of preventive administration of 50 mg oral pregabalin and 1 g paracetamol with 75 mg oral pregabalin and 1 g intravenous paracetamol on Numeric Rating Scale (NRS) scores and SP levels after cesarean section with spinal anesthesia. AIM: The objective of the study was to compare the effect of preventive administration of 50 mg oral pregabalin and 1 g paracetamol with 75 mg oral pregabalin and 1 g intravenous paracetamol on NRS scores and SP levels after cesarean section with spinal anesthesia. METHODS: This study used a double-blind randomized trial design. Samples were selected randomly and consecutively from the entire population that met the inclusion criteria. There were a total of 30 samples. SP levels were measured 2 h before cesarean section. The study drug was administered by mouth with a sip of water 1 h before the expected time of the surgical incision. SP levels were checked at the 4th h (SP 1) and 6th h (SP 2) postoperatively. The assessment of the degree of pain using the NRS was carried out at 2 h, 4 h, 6 h, 12 h, and 24 h postoperatively. This study used the Mann–Whitney U-test to compare both the levels of SP and NRS between the two groups. RESULTS: The results of this study showed that there was a significant difference in the NRS scores between the 50 mg and 75 mg pregabalin groups (p < 0.05). In the 75 mg pregabalin group, the NRS scores were lower than in the 50 mg pregabalin group in patients undergoing CS surgery under spinal anesthesia. There was a significant difference in SP levels between the 50 mg and 75 mg pregabalin groups (p < 0.05). SP levels in the 50 mg pregabalin group increased at 4 h and 6 h postoperatively, while in the 75 mg pregabalin group, it tended to decrease at 4 h and 6 h postoperatively. CONCLUSION: The quiescent and mobile NRS scores in the 75 mg pregabalin group were lower than the 50 mg pregabalin group with a combination of 1 g intravenous paracetamol after SC surgery. SP levels in the 75 mg pregabalin group decreased compared to the 50 mg pregabalin group with a 1 g intravenous paracetamol combination which experienced an increase after CS surgery. Pregabalin 75 mg is recommended for preventive use in CS surgery.

High-flow continuous hemodiafiltration successfully decreased blood pregabalin levels in a patient with severe pregabalin intoxication: a case report

Background

Severe pregabalin intoxication may cause serious symptoms, such as coma. Since pregabalin is a small molecule with no protein binding sites and has low volume of distribution, hemodialysis can be effective in eliminating pregabalin from the blood. However, in cases of emergency, it is not always possible to perform hemodialysis because of limited availability and time delay associated with using the plumbing equipment. Continuous hemodiafiltration (CHDF) can be performed without plumbing equipment; however, the knowledge on the effectiveness of CHDF in pregabalin elimination is insufficient.

Case presentation

A septuagenarian woman with normal renal function was found in a collapsed state with symptoms of coma and miosis. Empty medical bags of pregabalin (2350 mg), bepotastine besilate (600 mg), celecoxib (4600 mg), quetiapine fumarate (87.5 mg), clotiazepam (180 mg), and teprenone (50 mg) were found around her. During the patient's transfer to our hospital, her cognition worsened and she developed glossoptosis necessitating her emergent intubation upon arrival. We considered that the coma was mainly caused by pregabalin intoxication and were concerned about the consequent critical comorbidities. Thus, we performed CHDF in a high-flow setting in our intensive care unit for pregabalin elimination. After 8 h of CHDF, the patient regained consciousness, and after 6.5 h we extubated her. At a later date, we measured her serum pregabalin levels during the clinical course and estimated the blood pregabalin clearance levels depending on her metabolism as 76.8 mL/min and depending on CHDF itself as 65.1 mL/min. Based on these findings, we concluded that CHDF contributed to reducing blood pregabalin levels in this patient.

Conclusions

Our case revealed that pregabalin clearance using CHDF is similar to metabolic clearance in patients with normal renal function, indicating that CHDF decreases blood pregabalin levels and can be a potential treatment for severe pregabalin intoxication.

Pregabalin for chemotherapy-induced neuropathy: background and rationale for further study

Chemotherapy-induced neuropathy is difficult to manage, and the pain associated with neuropathy is poorly responsive to gabapentin in a randomized trial. Duloxetine is the only drug that has been found to be effective in reducing pain from chemotherapy neuropathy. In this qualitative review, the use of pregabalin for chemotherapy-induced neuropathy is discussed including the rationale and pharmacological reasons why pregabalin should be considered in a large, randomized placebo-controlled trial.

IMI2-PainCare-BioPain-RCT2 protocol: a randomized, double-blind, placebo-controlled, crossover, multicenter trial in healthy subjects to investigate the effects of lacosamide, pregabalin, and tapentadol on biomarkers of pain processing observed by non-invasive neurophysiological measurements of human spinal cord and brainstem activity

Background

IMI2-PainCare-BioPain-RCT2 is one of four similarly designed clinical studies aiming at profiling a set of functional biomarkers of drug effects on specific compartments of the nociceptive system that could serve to accelerate the future development of analgesics. IMI2-PainCare-BioPain-RCT2 will focus on human spinal cord and brainstem activity using biomarkers derived from non-invasive neurophysiological measurements.

Methods

This is a multisite, single-dose, double-blind, randomized, placebo-controlled, 4-period, 4-way crossover, pharmacodynamic (PD) and pharmacokinetic (PK) study in healthy subjects. Neurophysiological biomarkers of spinal and brainstem activity (the RIII flexion reflex, the N13 component of somatosensory evoked potentials (SEP) and the R2 component of the blink reflex) will be recorded before and at three distinct time points after administration of three medications known to act on the nociceptive system (lacosamide, pregabalin, tapentadol), and placebo, given as a single oral dose in separate study periods. Medication effects on neurophysiological measures will be assessed in a clinically relevant hyperalgesic condition (high-frequency electrical stimulation of the skin), and in a non-sensitized normal condition. Patient-reported outcome measures (pain ratings and predictive psychological traits) will also be collected; and blood samples will be taken for pharmacokinetic modelling. A sequentially rejective multiple testing approach will be used with overall alpha error of the primary analysis split between the two primary endpoints, namely the percentage amplitude changes of the RIII area and N13 amplitude under tapentadol. Remaining treatment arm effects on RIII, N13 and R2 recovery cycle are key secondary confirmatory analyses. Complex statistical analyses and PK-PD modelling are exploratory.

Discussion

The RIII component of the flexion reflex is a pure nociceptive spinal reflex widely used for investigating pain processing at the spinal level. It is sensitive to different experimental pain models and to the antinociceptive activity of drugs. The N13 is mediated by large myelinated non-nociceptive fibers and reflects segmental postsynaptic response of wide dynamic range dorsal horn neurons at the level of cervical spinal cord, and it could be therefore sensitive to the action of drugs specifically targeting the dorsal horn. The R2 reflex is mediated by large myelinated non-nociceptive fibers, its circuit consists of a polysynaptic chain lying in the reticular formation of the pons and medulla. The recovery cycle of R2 is widely used for assessing brainstem excitability. For these reasons, IMI2-PainCare-BioPain-RCT2 hypothesizes that spinal and brainstem neurophysiological measures can serve as biomarkers of target engagement of analgesic drugs for future Phase 1 clinical trials. Phase 2 and 3 clinical trials could also benefit from these tools for patient stratification.

Trial registration

This trial was registered on 02 February 2019 in EudraCT (2019-000755-14).

Osteogenic Effect of Pregabalin in Human Primary Mesenchymal Stem Cells, Osteoblasts, and Osteosarcoma Cells

Seventy million patients worldwide are suffering from epilepsy. The long-term use of antiepileptic drugs causes the alteration of the bone tissue and its metabolism, thus increasing the risk of fractures. Clinical and pre-clinical studies have highlighted conflicting data on the influence of the relatively new antiepileptic drug pregabalin (Lyrica^®). The objective of the present study was therefore to investigate its cytotoxicity in primary human osteoblasts (hOB). HOB and human mesenchymal stem cells (hMSC) were isolated from patients. The human osteosarcoma cells MG63 were included as established cell line. Cells were incubated with pregabalin at concentrations ranging from 0 to 40 μg/mL. Time-dependent cell proliferation was measured by automatic cell counting, and metabolism was determined by XTT assay and osseous differentiation by alkaline phosphatase (ALP) activity. Histological examinations of calcium deposit were performed with ALP, Alizarin Red, and von Kossa staining. A concentration-dependent increase in the proliferation of hOB and hMSC was observed after treatment with pregabalin. All cells showed a significant increase in cell metabolism. The osteogenic differentiation, confirmed by the increase of calcium deposit, was promoted by the administration of pregabalin. This effect was already significant at the therapeutic plasma concentration of pregabalin (10 μg/mL). In contrast to the other antiepileptic drugs, pregabalin showed no osteocatabolic effects. Conflicting in-vivo data must therefore be attributed to systemic effects of pregabalin.

IMI2-PainCare-BioPain-RCT1: study protocol for a randomized, double-blind, placebo-controlled, crossover, multi-center trial in healthy subjects to investigate the effects of lacosamide, pregabalin, and tapentadol on biomarkers of pain processing observed by peripheral nerve excitability testing (NET)

Background

Few new drugs have been developed for chronic pain. Drug development is challenged by uncertainty about whether the drug engages the human target sufficiently to have a meaningful pharmacodynamic effect. IMI2-PainCare-BioPain-RCT1 is one of four similarly designed studies that aim to link different functional biomarkers of drug effects on the nociceptive system that could serve to accelerate the future development of analgesics. This study focusses on biomarkers derived from nerve excitability testing (NET) using threshold tracking of the peripheral nervous system.

Methods

This is a multisite single-dose, subject and assessor-blind, randomized, placebo-controlled, 4-period, 4-way crossover, pharmacodynamic (PD), and pharmacokinetic (PK) study in healthy subjects. Biomarkers derived from NET of large sensory and motor fibers and small sensory fibers using perception threshold tracking will be obtained before and three times after administration of three medications known to act on the nociceptive system (lacosamide, pregabalin, tapentadol) and placebo, given as a single oral dose with at least 1 week apart. Motor and sensory NET will be assessed on the right wrist in a non-sensitized normal condition while perception threshold tracking will be performed bilaterally on both non-sensitized and sensitized forearm skin. Cutaneous high-frequency electrical stimulation is used to induce hyperalgesia. Blood samples will be taken for pharmacokinetic purposes and pain ratings as well as predictive psychological traits will be collected. A sequentially rejective multiple testing approach will be used with overall alpha error of the primary analysis split across the two primary outcomes: strength-duration time constant (SDTC; a measure of passive membrane properties and nodal persistent Na+ conductance) of large sensory fibers and SDTC of large motor fibers comparing lacosamide and placebo. The key secondary endpoint is the SDTC measured in small sensory fibers. Remaining treatment arm effects on key NET outcomes and PK modelling are other prespecified secondary or exploratory analyses.

Discussion

Measurements of NET using threshold tracking protocols are sensitive to membrane potential at the site of stimulation. Sets of useful indices of axonal excitability collectively may provide insights into the mechanisms responsible for membrane polarization, ion channel function, and activity of ionic pumps during the process of impulse conduction. IMI2-PainCare-BioPain-RCT1 hypothesizes that NET can serve as biomarkers of target engagement of analgesic drugs in this compartment of the nociceptive system for future Phase 1 clinical trials. Phase 2 and 3 clinical trials could also benefit from these tools for patient stratification.

Trial registration

This trial was registered 25/06/2019 in EudraCT (2019-000942-36).

Extracorporeal Treatment for Gabapentin and Pregabalin Poisoning: Systematic Review and Recommendations From the EXTRIP Workgroup

Toxicity from gabapentin and pregabalin overdose is commonly encountered. Treatment is supportive, and the use of extracorporeal treatments (ECTRs) is controversial. The EXTRIP workgroup conducted systematic reviews of the literature and summarized findings following published methods. Thirty-three articles (30 patient reports and 3 pharmacokinetic studies) met the inclusion criteria. High gabapentinoid extracorporeal clearance (>150mL/min) and short elimination half-life (<5 hours) were reported with hemodialysis. The workgroup assessed gabapentin and pregabalin as "dialyzable" for patients with decreased kidney function (quality of the evidence grade as A and B, respectively). Limited clinical data were available (24 patients with gabapentin toxicity and 7 with pregabalin toxicity received ECTR). Severe toxicity, mortality, and sequelae were rare in cases receiving ECTR and in historical controls receiving standard care alone. No clear clinical benefit from ECTR could be identified although major knowledge gaps were acknowledged, as well as costs and harms of ECTR. The EXTRIP workgroup suggests against performing ECTR in addition to standard care rather than standard care alone (weak recommendation, very low quality of evidence) for gabapentinoid poisoning in patients with normal kidney function. If decreased kidney function and coma requiring mechanical ventilation are present, the workgroup suggests performing ECTR in addition to standard care (weak recommendation, very low quality of evidence).

Development of Physiologically Based Pharmacokinetic Model for Pregabalin to Predict the Pharmacokinetics in Pediatric Patients with Renal Impairment and Adjust Dosage Regimens: PBPK Model of Pregabalin in Pediatric Patients with Renal Impairment

Pregabalin (PGB) is widely used clinically; however, its pharmacokinetics (PK) has not been studied in pediatric patients with renal impairment (RI). To design optimized PGB regimens for pediatric patients with varying degrees of RI and predict exposure to PGB, physiologically based pharmacokinetic (PBPK) models of PGB were developed and verified, and its disposition was simulated in the healthy population and adults with RI. The simulated results from the PBPK models after single-dose and multi-dose administrations of PGB were consistent with the corresponding observed data based on the fold error values of less than 2. The area under curve ratios were 1.23 ± 0.06, 2.02 ± 0.10, 3.86 ± 0.21, and 9.92 ± 0.79 in pediatric patients with mild, moderate, severe, and end-stage RI, respectively. Based on the predictions for pediatric patients with moderate, severe, and end-stage RI, the maximum dose should not exceed 7, 3.5, and 1.4 mg/kg/day, respectively, among those weighing < 30 kg, and it should not exceed 5, 2.5, and 1 mg/kg/day, respectively, among those weighing > 30 kg. In conclusion, the developed PBPK model is a valuable tool for predicting PGB dosage for pediatric patients with RI.

Biotransformation of pregabalin in surface water matrices and the occurrence of transformation products in the aquatic environment - comparison to the structurally related gabapentin

The biodegradability of the anticonvulsant pregabalin (PGB) was studied in laboratory incubation experiments in contact with water/sediment systems under different redox conditions. PGB was degraded by biological processes under aerobic conditions reaching half-lives of 8 to 10 d, while inactivated and anaerobic control experiments revealed no significant decrease of PGB concentrations. Within experiments spiked with elevated PGB concentrations, 12 TPs were formed and tentative chemical structures could be proposed by accurate masses and fragmentation pathways detected via measurements with high resolution mass spectrometry (LC-QToF-MS). Four of the proposed TPs were finally confirmed either by authentic reference standards (PGB-Lactam, ISA, TP 157-A (II)) or a self-synthesized standard (NA-PGB). PGB-Lactam was identified as the quantitatively most relevant TP formed via intramolecular cyclization under aerobic conditions, reaching up to 33% of the initial PGB concentration. Incubation experiments spiked with PGB-Lactam revealed three times higher half-lives compared to the parent compound, indicating that PGB-Lactam is more stable than PGB. A comparison with results gained from water/sediment incubation experiments with the structurally related compound gabapentin (GBP) revealed, that the transformation behaviour can be mainly extrapolated to PGB. Most of the observed transformation reactions found for PGB were comparable to the ones found for GBP. The TPs PGB-Lactam and NA-PGB as well as three GBP TPs (GBP-Lactam, NA-GBP and CCHA) have been detected in German wastewater treatment plants (WWTPs) effluents and the river Rhine including some of its tributaries such as Main, Neckar, Moselle and Aare. Moreover, GBP and PGB as well as some of their TPs were detected in German bank filtrates and finished drinking waters up to 260 ng L^-1. For that reason these compounds should be monitored in drinking water in the future.

IMI2-PainCare-BioPain-RCT3: a randomized, double-blind, placebo-controlled, crossover, multi-center trial in healthy subjects to investigate the effects of lacosamide, pregabalin, and tapentadol on biomarkers of pain processing observed by electroencephalography (EEG)

Background

IMI2-PainCare-BioPain-RCT3 is one of four similarly designed clinical studies aiming at profiling a set of functional biomarkers of drug effects on the nociceptive system that could serve to accelerate the future development of analgesics, by providing a quantitative understanding between drug exposure and effects of the drug on nociceptive signal processing in human volunteers. IMI2-PainCare-BioPain-RCT3 will focus on biomarkers derived from non-invasive electroencephalographic (EEG) measures of brain activity.

Methods

This is a multisite single-dose, double-blind, randomized, placebo-controlled, 4-period, 4-way crossover, pharmacodynamic (PD) and pharmacokinetic (PK) study in healthy subjects. Biomarkers derived from scalp EEG measurements (laser-evoked brain potentials [LEPs], pinprick-evoked brain potentials [PEPs], resting EEG) will be obtained before and three times after administration of three medications known to act on the nociceptive system (lacosamide, pregabalin, tapentadol) and placebo, given as a single oral dose in separate study periods. Medication effects will be assessed concurrently in a non-sensitized normal condition and a clinically relevant hyperalgesic condition (high-frequency electrical stimulation of the skin). Patient-reported outcomes will also be collected. A sequentially rejective multiple testing approach will be used with overall alpha error of the primary analysis split between LEP and PEP under tapentadol. Remaining treatment arm effects on LEP or PEP or effects on EEG are key secondary confirmatory analyses. Complex statistical analyses and PK-PD modeling are exploratory.

Discussion

LEPs and PEPs are brain responses related to the selective activation of thermonociceptors and mechanonociceptors. Their amplitudes are dependent on the responsiveness of these nociceptors and the state of the pathways relaying nociceptive input at the level of the spinal cord and brain. The magnitude of resting EEG oscillations is sensitive to changes in brain network function, and some modulations of oscillation magnitude can relate to perceived pain intensity, variations in vigilance, and attentional states. These oscillations can also be affected by analgesic drugs acting on the central nervous system. For these reasons, IMI2-PainCare-BioPain-RCT3 hypothesizes that EEG-derived measures can serve as biomarkers of target engagement of analgesic drugs for future Phase 1 clinical trials. Phase 2 and 3 clinical trials could also benefit from these tools for patient stratification.

Trial registration

This trial was registered 25/06/2019 in EudraCT (2019%2D%2D001204-37).

An open-label pilot study of pregabalin pharmacotherapy for alcohol use disorder

Background: There is a need for alcohol use disorder (AUD) pharmacotherapy that can be administered to actively drinking outpatients. Pregabalin, a gabapentoid anticonvulsant, has preliminary evidence supporting effects on alcohol withdrawal and AUD.Objectives: To evaluate the safety, tolerability, and optimal dosing of pregabalin for treating AUD.Methods: In an open-label, 8-week, outpatient trial of eighteen adults (nine women) with AUD, participants were titrated to 600 mg/day (or the maximum tolerated dose) over 3 weeks and then maintained for 5 weeks.Results: The majority (11/14, 78.6%) of participants with at least one-week of medication exposure achieved a maximum dose of 600 mg/day. Mean retention was 6.8 weeks (SD = 2.6). Eighty percent (12/15) of participants with post-enrollment data reported any adverse effects during the trial; and for those reporting adverse effects the most common were drowsiness (33.3%, 4/12), and fogginess (25%, 3/12), dizziness (25%, 3/12), and insomnia (25%, 3/12). Two participants discontinued study medication due to adverse effects and one had a dose reduction. Mean Heavy Drinking Days (HDD)/week decreased significantly by 3.43 days (SD = 2.47; median (IQR) = 4.00 (1.00 to 5.50)); Wilcoxon signed rank test statistic ((S) = 49.5, p = .0006). Mean proportion of HDD significantly decreased on average by 48.7% (SD = 35.1%; median (IQR) = 57.1% (14.3% to 78.6%)). The proportion of abstinent days increased significantly on average by 36.1% (SD = 35.0%; median (IQR) = 17.9% (14.3% to 75.0%); S = 49.5, p = .0005).Conclusions: Pregabalin treatment of AUD appears to be safe and well tolerated in doses up to 600 mg per day.Trial Registration: clinicaltrials.gov identifier: NCT03256253.

Do gabapentin or pregabalin directly modulate the µ receptor?

BACKGROUND

Pregabalin and gabapentin improve neuropathic pain symptoms but there are emerging concerns regarding their misuse. This is more pronounced among patients with substance use disorder, particularly involving opioids. Co-ingestion of gabapentinoids with opioids is increasingly identified in opioid related deaths, however, the molecular mechanism behind this is still unclear. We have sought to determine whether pregabalin or gabapentin directly modulates acute μ receptor signaling, or μ receptor activation by morphine.

METHODS

The effects of pregabalin and gabapentin were assessed in HEK 293 cells stably transfected with the human μ receptor. Their effect on morphine induced hyperpolarization, cAMP production and ERK phosphorylation were studied using fluorescent-based membrane potential assay, bioluminescence based CAMYEL assay and ELISA assay, respectively. Pregabalin/gabapentin effects on morphine-induced hyperpolarization were also investigated in AtT20 cells.

RESULTS

Pregabalin or gabapentin (1 µM, 100 µM each) did not activate the µ receptor or affect K channel activation or ERK phosphorylation produced by morphine. Neither drug affected the desensitization of K channel activation produced by prolonged (30 min) application of morphine. Gabapentin (1 µM, 100 µM) and pregabalin (1 µM) did not affect inhibition of forskolin-stimulated cAMP production by morphine. However, pregabalin (100 µM) potentiated forskolin mediated cAMP production, although morphine still inhibited cAMP levels with a similar potency to control.

DISCUSSION

Pregabalin or gabapentin did not activate or modulate µ receptor signaling in three different assays. Our data do not support the hypothesis that gabapentin or pregabalin augment opioid effects through direct or allosteric modulation of the µ receptor. Pregabalin at a high concentration increases cAMP production independent of morphine. The mechanism of enhanced opioid-related harms from co-ingestion of pregabalin or gabapentin with opioids needs further investigation.

Pregabalin for neuropathic pain in primary care settings: recommendations for dosing and titration

Pregabalin is one of the first-line treatments approved for the management of neuropathic pain (NeP). While many patients benefit from treatment with pregabalin, they are often treated with suboptimal doses, possibly due to unfamiliarity around prescribing the drug and/or side effects that can occur with up-titration. This narrative review discusses key aspects of initiating, titrating, and managing patients prescribed pregabalin therapy, and addresses concerns around driving and the potential for abuse, as well as when to seek specialist opinion. To ensure that patients derive maximum therapeutic benefit from the drug, we suggest a 'low and slow' dosing approach to limit common side effects and optimize tolerability alongside patients' expectations. When requiring titration to higher doses, we recommend initiating 'asymmetric dosing,' with the larger dose in the evening. Fully engaging patients in order for them to understand the expected timeline for efficacy and side effects (including their resolution), can also help determine the optimal titration tempo for each individual patient. The 'low and slow' approach also recognizes that patients with NeP are heterogeneous in terms of their optimal therapeutic dose of pregabalin. Hence, it is recommended that general practitioners closely monitor patients and up-titrate according to pain relief and side effects to limit suboptimal dosing or premature discontinuation.

Pregabalin Population Pharmacokinetic and Exposure-Response Analyses for Focal Onset Seizures in Children (4-16 years) and Adults, to Support Dose Recommendations in Children

Pregabalin is approved in multiple countries as adjunctive therapy for adult patients with focal onset seizures (FOS; previously termed partial onset seizures). This study used population pharmacokinetic (PK) and exposure–response (E‐R) analyses from pooled pregabalin concentration and efficacy data to compare pregabalin exposure and E‐R relationships in pediatric and adult patients with FOS, to support pediatric dosage recommendations. A one‐compartment disposition model was used, with first‐order absorption and body surface area‐normalized creatinine clearance on clearance. Individual pregabalin average steady‐state concentrations were predicted and used in an E‐R analysis of efficacy. The E‐R relationship of pregabalin was similar in pediatric (4–16 years) and adult patients with FOS after accounting for differences in baseline natural log‐transformed 28‐day seizure rate and placebo effect. Population PK simulations showed that children aged 4–16 years and weighing ≥ 30 kg required pregabalin 2.5–10 mg/kg/day to achieve similar pregabalin exposure at steady‐state to adult patients receiving the approved doses of 150–600 mg/day. For children 4–16 years weighing < 30 kg, a higher pregabalin dose of 3.5–14 mg/kg/day was required to achieve equivalent exposure at steady‐state. The results support the dosage guidance provided in the pregabalin prescribing label, whereby pediatric patients (4–16 years) weighing < 30 kg should receive a 40% higher pregabalin dose (per kg of body weight) than patients weighing ≥ 30 kg to achieve similar exposure. Our combined modeling approach may provide guidance for future extrapolation assessment from adult to pediatric patients.

Beyond Amitriptyline: A Pediatric and Adolescent Oriented Narrative Review of the Analgesic Properties of Psychotropic Medications for the Treatment of Complex Pain and Headache Disorders

Children and adolescents with recurrent or chronic pain and headache are a complex and heterogenous population. Patients are best served by multi-specialty, multidisciplinary teams to assess and create tailored, individualized pain treatment and rehabilitation plans. Due to the complex nature of pain, generalizing pharmacologic treatment recommendations in children with recurrent or chronic pains is challenging. This is particularly true of complicated patients with co-existing painful and psychiatric conditions. There is an unfortunate dearth of evidence to support many pharmacologic therapies to treat children with chronic pain and headache. This narrative review hopes to supplement the available treatment options for this complex population by reviewing the pediatric and adult literature for analgesic properties of medications that also have psychiatric indication. The medications reviewed belong to medication classes typically described as antidepressants, alpha 2 delta ligands, mood stabilizers, anti-psychotics, anti-sympathetic agents, and stimulants.

Preoperative oral pregabalin for anxiety control: a systematic review

OBJECTIVE

The objective of this systematic review was to determine the effectiveness of preoperative oral pregabalin for anxiety control, the most effective dosage regimen, its impact on postoperative pain, and its adverse effects.

MATERIALS AND METHODS

A search was conducted of PubMed/Medline and clinicaltrials.gov (National Library of Medicine, Washington, DC), Scopus, Web of Science, and Cochrane databases for studies published between January 2009 and November 2018, with no language restriction. Based on PRISMA guidelines, the specific question was: is preoperative oral pregabalin effective and safe for anxiety control in patients undergoing surgery? The critical reading of retrieved studies followed questions prepared by the CASPe Network, and their methodological quality was evaluated using the Jadad Scale.

RESULTS

Twelve randomized controlled trials were selected for review. All twelve studies were trials of high quality. A dose of 75 mg preoperative oral pregabalin has been found to reduce anxiety and stabilize intraoperative hemodynamics, although a more significant improvement appears to be achieved with a single dose of 150 mg pregabalin at least 1 h before the surgery. It is not associated with any severe adverse effects.

CONCLUSION

Preoperative administration of oral pregabalin in a single dose of 150 mg appears to be effective to significantly reduce the anxiety of patients, intraoperative hemodynamic changes, and postoperative pain.

CLINICAL RELEVANCE

These findings suggest that pregabalin is useful and safe for preoperative and intraoperative anxiety control in patients undergoing surgery.

[Pregabalin and risk of addiction: A new care issue?]

PURPOSE

Pregabalin (PRG) is a gamma-aminobutyric acid (GABA) analogue used for treatment of epilepsy, neuropathic pain, generalised anxiety disorder and currently being studied for other indications. Supported by the results of case studies and a limited number of studies, there is an ongoing debate about the addictive potential of PRG. However, evidence is scarce and no definitive assessment on the potential for abuse and dependence to PRG is available. The objective of our study was to identify the number of cases of abuse or dependence to PRG published and to study potential risk factors of addiction to PRG.

METHODS

We have identified on PubMed and ScienceDirect published case studies of PRG abuse or dependence and analysed these cases on the basis of several clinical parameters.

RESULTS

A total of 118 cases of PRG abuse or dependence were identified, including 21 isolated cases (mean age 33 years, 67 % men). The mean daily dose of PRG was 2,9 g. Current or past polydrug abuse was present in the majority of cases. Psychiatric diagnoses, other than substance-related disorders, were reported in as many patients, and almost all patients experienced withdrawal symptoms when PRG was discontinued.

CONCLUSION

Current literature suggests an important and growing concern for the abuse of PRG. Male sex, psychiatric and/or addiction history, including opioid addiction, may be potential risk factors for the development of addictive behaviours associated with PRG.

Pregabalin as a Pain Therapeutic: Beyond Calcium Channels

Initially developed to generate new treatments for epilepsy, gabapentin, and pregabalin (“gabapentinoids”) were engineered to mimic the action of GABA and to modulate GABA metabolism. Rather than their intended pharmacological action on GABA neurotransmission, instead, they exhibit a high affinity for the α2δ-1 and α2δ-2 subunits of voltage-activated calcium channels, wherein binding of gabapentinoids inhibits cellular calcium influx and attenuates neurotransmission. Despite a lack of activity on GABA levels, gabapentin and pregabalin are effective at suppressing seizures and subsequently approved as a new class of antiepileptic therapy for partial-onset epilepsy. Through the same hypothesized molecular mechanism and by controlling neuronal hyperexcitability, gabapentinoids demonstrate clear efficacy in pain management, which has arguably been their most extensively prescribed application to date. In this review, we focus on pregabalin as a second-generation gabapentinoid widely employed in the treatment of a variety of pain conditions. We also discuss the wider functional roles of α2δ subunits and the contributions that pregabalin might play in affecting physiological and pathophysiological processes.

Development of a Novel Controlled-Release Tablet of Pregabalin: Formulation Variation and Pharmacokinetics in Dogs and Humans

Background

Novel three-layered (TL) tablet systems were compared with both monolithic matrix (MM) formulations and a commercial immediate-release (IR) capsule to develop once-a-day (OAD) pregabalin tablets.

Methods

The physical properties of the TL tablets, including dissolution and swelling rates, were compared with those of the MM tablets and the pharmacokinetic parameters of the TL tablet were compared with those of an IR capsule in beagles and humans.

Results

Our results indicated that the same amount of a hydrophilic polymer in the formulations had similar dissolution profiles at 12 h, regardless of the tablet geometry. However, the degree of tablet swelling differed, with larger amounts of polymer in the tablets showing a greater degree of swelling. In addition, TL tablets swelled more rapidly compared with MM tablets. For the pharmacokinetic study of the TL tablet, the beagles demonstrated absorption results similar to those of an IR capsule, whereas the humans demonstrated low total absorption compared with an IR capsule. The time of the peak plasma concentration at 6 h in the fed state of humans coincided with the results of the study on beagles.

Conclusion

The novel TL tablet system of pregabalin may prove to be helpful in developing improved formulations with better continuous drug absorption for OAD administration.

An Insight into Gabapentin and Pregabalin in Scottish Prisoners

The aim of this study was to evaluate the prevalence and abuse potential of antiepileptic drugs (AEDs) among prison populations in Scotland, UK. Participants consisted of all admitted and released prisoners over a 1 month period who consented to provide samples. Urine samples were collected and analyzed by liquid chromatography coupled with triple quadrupole tandem mass spectrometry using a method validated for the simultaneous quantification of 21 AEDs in urine. A total of 904 samples were collected. The samples were also screened for drugs of abuse by using point-of-care testing kits. A total of 18% of the samples were positive for AEDs. Gabapentin (GBP) was identified in 118 samples (13%) and pregabalin (PRG) in 32 samples (3.5%). Interestingly, 12 samples contained both drugs (1.3%). The concentrations ranged from 0.5 to 1,100 mg/L (median, 15 mg/L) for GBP and from 0.5 to 440 mg/L (median, 7.3 mg/L) for PRG. Four samples were found to have concentrations &gt;400 mg/L, two samples for GBP and two samples for PRG. These concentrations are at least 20 times above the median concentrations. Other AEDs detected were levetiracetam (four samples), vigabatrin (four samples), lamotrigine (three samples), valproic acid (three samples), carbamazepine (two samples) and topiramate (one sample). Illicit or non-prescribed drugs were detected in 81% of urine samples of which 80% were from admitted prisoners and 20% from released prisoners. Benzodiazepines, opiates and cannabis were the most frequently detected drugs. Other drugs found in positive AED samples were methadone (26%), cocaine (18%), buprenorphine (17%), amphetamines (4%), methamphetamines (4%) and barbiturates (4%). This study shows a high prevalence of AEDs within the Scottish prison system, primarily due to GBP and PRG; however, due to the anonymity of the sample collection, it is unknown if these are prescribed or illicit drug ingestions.

A data science approach to the selection of most informative readouts of the human intradermal capsaicin pain model to assess pregabalin effects

Persistent and, in particular, neuropathic pain is a major healthcare problem with still insufficient pharmacological treatment options. This triggered research activities aimed at finding analgesics with a novel mechanism of action. Results of these efforts will need to pass through the phases of drug development, in which experimental human pain models are established components e.g. implemented as chemical hyperalgesia induced by capsaicin. We aimed at ranking the various readouts of a human capsaicin-based pain model with respect to the most relevant information about the effects of a potential reference analgesic. In a placebo-controlled, randomized cross-over study, seven different pain-related readouts were acquired in 16 healthy individuals before and after oral administration of 300 mg pregabalin. The sizes of the effect on pain induced by intradermal injection of capsaicin were quantified by calculating Cohen's d. While in four of the seven pain-related parameters, pregabalin provided a small effect judged by values of Cohen's d exceeding 0.2, an item categorization technique implemented as computed ABC analysis identified the pain intensities in the area of secondary hyperalgesia and of allodynia as the most suitable parameters to quantify the analgesic effects of pregabalin. Results of this study provide further support for the ability of the intradermal capsaicin pain model to show analgesic effects of pregabalin. Results can serve as a basis for the designs of studies where the inclusion of this particular pain model and pregabalin is planned.

Customized Novel Design of 3D Printed Pregabalin Tablets for Intra-Gastric Floating and Controlled Release Using Fused Deposition Modeling

Three-dimensional (3D) printing has been recently employed in the design and formulation of various dosage forms with the aim of on-demand manufacturing and personalized medicine. In this study, we formulated a floating sustained release system using fused deposition modeling (FDM). Filaments were prepared using hypromellose acetate succinate (HPMCAS), polyethylene glycol (PEG 400) and pregabalin as the active ingredient. Cylindrical tablets with infill percentages of 25%, 50% and 75% were designed and printed with the FDM printer. An optimized formulation (F6) was designed with a closed bottom layer and a partially opened top layer. Filaments and tablets were characterized by means of fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), and thermogravimetric analysis (TGA). The results show that the processing condition did not have a significant effect on the stability of the drug and the crystallinity of the drug remained even after printing. A dissolution study revealed that drug release is faster in an open system with low infill percentage compared to closed systems and open systems with a high infill ratio. The optimized formulation (F6) with partially opened top layer showed zero-order drug release. The results show that FDM printing is suitable for the formulation of floating dosage form with the desired drug release profile.

Demonstrating suitability of the Caco-2 cell model for BCS-based biowaiver according to the recent FDA and ICH harmonised guidelines

Objective

According to the regulatory guidelines, one of the critical steps in using in-vitro permeability methods for permeability classification is to demonstrate the suitability of the method. Here, suitability of the permeability method by using a monolayer of cultured epithelial cells was verified with different criteria.

Methods

Imaging with a transmission electron microscope was used for characterisation of the cells. Monolayer integrity was confirmed by transepithelial electrical resistance measurements and permeability of zero permeability marker compounds. Real-time polymerase chain reaction was employed to evaluate expression levels of 84 known transporters. Samples for bidirectional permeability determination were quantified by ultra-performance liquid chromatography.

Key findings

The Caco-2 cells grow in an intact monolayer and morphologically resemble enterocytes. Genes of 84 known transporters were expressed at different levels; furthermore, expression was time depended. Functional expression of efflux transporter P-glycoprotein was confirmed. We established a correlation between permeability coefficients of 21 tested drug substances ranging from low, moderate and high absorption with human fraction absorbed literature data (R2 = 0.84).

Conclusions

Assay standardisation assures the consistency of experimental data. Only such fully characterised model has the ability to accurately predict drug's intestinal permeability at the early stage of research or for the BCS-based biowaiver application.

Low-dose preoperative pregabalin improves postoperative pain management in septorhinoplasty surgery: a double-blind randomized clinical trial

PURPOSE

To evaluate the efficacy of single low dose (75 mg) preoperative pregabalin in reducing post-operative pain of septorhinoplasty.

METHODS

A double blind single center Randomized controlled trial based on block randomization. In the pregabalin group (PG) 34 participants received 75 mg pregabalin orally one hour before anesthesia induction while in control group (CG) 34 participants received a placebo. Pain and sedation were repeatedly measured with Visual Analouge Scale (VAS) and Riker Sedation-Agitation Scale (RSAS) respectively, 0.5, 1, 2, 6, 24 hours postextubation. Cumulative doses of fentanyl and ibuprofen received in both groups were compared.

RESULTS

Thirty-two of the participants in PG and 33 of the participants in CG completed the study. The Mean VAS pain score was less in PG versus CG 30 min postoperatively (2.30 ± 1.30 vs. 4.85 ± 1.17), one hour (2.28 ± 0.92 vs. 4.27 ± 0.78), two hours (2.11 ± 0.88 vs. 3.60 ± 0.61) and six hours (1.47 0.62 vs. 2.76 ± 0.91) but not 24-hours postoperatively (0.84 ± 0.62 vs. 1.09 ± 0.92). Participants in the PG were less agitated during early post-extubation period (at 10 min: RSAS 3.93 ± 0.43 vs. 4.42 ± 0.50) and more alert during the first hour post-extubation (at 60 min: RSAS 3.90 ± 0.29 vs. 3.36 ± 0.69). The total dose of rescue fentanyl and ibuprofen was lower in the PG compared to the CG.

CONCLUSIONS

A single dose of 75 mg pregabalin is very effective for pain control after septorhinoplasty procedure when administered one hour before anesthesia induction. Side effects are rare and opioid sparing was noted.

TRIAL REGISTRATION

Clinical trial number: IRCT2017043033706N1.

Impact of Cachexia and Opioid Analgesic Cotreatment on Pregabalin Pharmacokinetics and Central Nervous System Symptoms in Cancer Patients

BACKGROUND

Patients with cancer receiving pregabalin potentially have a high incidence of central nervous system (CNS) symptoms. The purpose of this study was to explore clinical factors influencing the incidence of CNS symptoms, including plasma pregabalin exposure, cancer cachexia, and opioid analgesic cotreatment.

METHODS

Sixty-eight patients with cancer receiving twice-daily pregabalin were enrolled. Plasma concentrations of pregabalin, clinical laboratory data, opioid analgesic cotreatment, and the Glasgow Prognostic Score, which is an inflammation-based cachexia score, were considered as clinical factors. The incidence of CNS symptoms was collected from the patients' medical records. The predose plasma concentrations of pregabalin at steady state were determined by ultra-high-performance liquid chromatography.

RESULTS

The steady-state trough plasma pregabalin concentrations showed a large variability with an interquartile range of 0.43-1.2 mg/L per mg/kg and were negatively correlated with an estimated glomerular filtration rate (eGFR). C-reactive protein (standardized partial regression coefficient, β = 0.31) and opioid analgesic cotreatment (β = 0.24) were also identified in addition to eGFR (β = -0.60) in the multiple regression analysis. The incidence of CNS symptoms was significantly increased with opioid analgesic cotreatment and a higher Glasgow Prognostic Score but not with the absolute value of plasma pregabalin concentrations, eGFR, or other clinical laboratory data.

CONCLUSIONS

In patients with cancer, steady-state trough plasma pregabalin concentrations were altered with renal function, systemic inflammation, and opioid analgesic cotreatment. However, a higher incidence of CNS symptoms observed in patients with cancer on pregabalin was more related to cachexia and opioid analgesic cotreatment than to altered pregabalin concentrations.

The effect of pregabalin treatment on balance and gait in patients with chronic low back pain: a retrospective observational study

Background: Low back pain is the most common musculoskeletal problem, and is a major cause of loss of workforce. Chronic low back pain associated with radiculopathy often includes nociceptive and neuropathic components. While non-steroidal anti-inflammatory drugs are the first choice for the nociceptive component, pregabalin is preferred as the neuropathic component.

Materials and methods: A retrospective analysis was conducted of 48 patients (26 women, 22 men) who had chronic low back pain associated with radiculopathy. A follow-up chart was used to collect data from February 2017 to November 2017. The patients characteristics (age, gender, initial daily dose of pregabalin), neuropathic pain (DN4 scale; Douleur Neuropathique, 4 questions), and balance and gait (Tinetti Balance and Gait Test) were assessed.

Results: The DN4 scores in the fourth (p < .001) and 12th (p < .001) weeks were significantly lower in patients. The Tinetti total test scores (23.2 ± 3.9) in the first (p > .001) week were significantly lower. There was no significant difference between the Tinetti test scores (balance, gait, and total scores) at baseline and in the 12th week (p > .001).

Conclusion: Pregabalin is effective on neuropathic pain and may have adverse effects on balance at initial doses and dose increments. Tolerance develops to these effects at maintenance doses.

Pregabalin in the Management of Painful Diabetic Neuropathy: A Narrative Review

Pregabalin is a first-line treatment in all major international guidelines on the management of painful diabetic neuropathy (pDPN). Treatment with pregabalin leads to a clinically meaningful improvement in pain scores, offers consistent relief of pain and has an acceptable tolerance level. Despite its efficacy in relieving neuropathic pain, more robust methods and comprehensive studies are required to evaluate its effects in relation to co-morbid anxiety and sleep interference in pDPN. The sustained benefits of modulating pain have prompted further exploration of other potential target sites and the development of alternative GABAergic agents such as mirogabalin. This review evaluates the role of pregabalin in the management of pDPN as well as its potential adverse effects, such as somnolence and dizziness, which can lead to withdrawal in ~ 30% of long-term use. Recent concern about misuse and an increase in deaths linked to its use has led to demands for reclassification of pregabalin as a class C controlled substance in the UK. We believe these demands need to be tempered in relation to the difficulties it would create for repeat prescriptions for the many millions of patients with pDPN for whom pregabalin provides benefit.Plain Language Summary: Plain language summary available for this article.

Evaluation of pregabalin-induced adverse events related to falls using the FDA adverse event reporting system and Japanese Adverse Drug Event Report databases

WHAT IS KNOWN AND OBJECTIVE

Pregabalin is used for neuropathic and postherpetic pain and generalized anxiety. The aim of this study was to obtain the onset profiles of adverse events (AE) related to falls (AEFs) such as "somnolence," "dizziness," "loss of consciousness" and "fall" onset and several clinical factor combinations such as age and administered dose, using spontaneous reporting system (SRS) analysis such as the US Food and Drug Administration Adverse Event Reporting System (FAERS) database and the Japanese Adverse Drug Event Report (JADER) database.

METHODS

We used the reporting odds ratio (ROR) to analyse the association between pregabalin and AEFs. Additionally, we used the time-to-onset analysis.

RESULTS AND DISCUSSION

The crude RORs of AEFs such as somnolence and dizziness were higher than one for both the databases. The adjusted RORs for AEFs in the ≥60 years age group compared to those in the <60 years age group for the FAERS and JADER databases were 1.46 (95% CI = 1.39-1.53; P < 0.0001) and 2.58 (95% CI = 2.06-3.27; P < 0.0001), respectively. In the JADER database, the median and quartile range for AEFs with pregabalin, at ≤75 and ≥100 mg/d, were 2.0 (0.0-5.0) and 2.0 (1.0-4.3) days, respectively. Additionally, 57.2% of AEFs (four preferred terms) were observed within 2 days after administration.

WHAT IS NEW AND CONCLUSIONS

This study is the first to evaluate the relationship between pregabalin and AEFs using the SRS analysis strategy. The risk of AEFs in the ≥60 years age group might increase compared to that in the <60 years age group. AEFs occurred almost within 1 week after pregabalin administration, and the median for AEF onset was 2 days. Our results show that patients should be closely monitored for AEFs for 1 week from the start of pregabalin administration.

Preoperative Low-dose and High-dose Pregabalin and Cardiovascular Response to Endotracheal Intubation: A Prospective, Randomized, Single-blind, Controlled Study in China

PURPOSE

A prospective, randomized, single-blind, controlled clinical study was designed to evaluate the efficacy and tolerability of preoperative pregabalin on cardiovascular response to laryngoscopy and endotracheal intubation.

METHODS

Patients aged 18-60 years with an American Society of Anesthesiologists scale score of I or II were recruited and randomly allocated to receive placebo (control), low-dose (150-mg) pregabalin, or high-dose (300-mg) pregabalin. The medications were orally administered 1 hour before general anesthesia. Heart rate, systolic and diastolic blood pressures, and mean arterial blood pressure were measured and recorded prior to the administration of placebo or pregabalin; before endotracheal intubation; and at 0, 1, 3, 5, 7, and 10 minutes after intubation. The sedation score was evaluated 1 hour after the administration of placebo or pregabalin.

FINDINGS

A total of 90 patients were enrolled (n = 30 per group). Pregabalin (150 or 300 mg) was associated with reduced blood pressure fluctuations after intubation, but with no significant differences between the 2 dose groups. Pregabalin was associated with an inhibitory effect on heart rate fluctuations and reduced hemodynamic complications after intubation, in a dose-dependent manner, but no effect on the required perioperative opioid dosage was found. Both doses were effective in reducing preoperative anxiety, but visual analog scale pain scores at 1 hour after surgery were reduced only in limb and spine as well as abdominal surgeries. A pregabalin-related adverse reaction was dizziness, which was observed at 1 hour after surgery in both groups.

IMPLICATIONS

In this study, high-dose (300-mg) pregabalin effectively attenuated cardiovascular response after endotracheal intubation. ClinicalTrials.gov identifier: NCT03456947.

Pain management in living related adult donor hepatectomy: feasibility of an evidence-based protocol in 100 consecutive donors

Objective

Living donor hepatectomy (LDH) has important consequences in terms of acute and chronic pain. We proposed an anesthetic protocol based on the best currently available evidence. We report the results of this protocol’s application.

Results

We performed a retrospective descriptive study of 100 consecutive donors undergoing LDH. The protocol included standardized information provided by the anesthetist, pharmacological anxiolysis and preventive analgesia. Specifically, pregabalin premedication (opioid-free) intravenous anesthesia (with clonidine, ketamine, magnesium sulphate and ketorolac) and epidural analgesia were proposed. Postoperative follow-up was conducted by the Postoperative Pain Service. This analysis included 100 patients (53 women, 47 men, median age 32.7 years old [28.4–37.3]), operated by xypho-umbilical laparotomy. All elements of our anesthetic protocol were applied in over 75% of patients, except for the preoperative consultation with a senior anesthesiologist (55%). The median number of applied item was 7 [interquartile range, IQR 5–7]. Median postoperative pain scores were, at rest and at mobilization respectively 3 [IQR 2–4] and 6 [IQR 4.5–7] on day 1; 2 [IQR 1–3] and 5 [IQR 3–6] on day 2; and 2 [IQR 0–3] and 4 [IQR 3–5] on day 3. In conclusion, LDH leads to severe acute pain. Despite the proposal of a multimodal evidence-based protocol, its applicancy was not uniform and the pain scores remained relatively high.

Electronic supplementary material

The online version of this article (10.1186/s13104-018-3941-1) contains supplementary material, which is available to authorized users.

Novel Insights of Effects of Pregabalin on Neural Mechanisms of Intracortical Disinhibition in Physiopathology of Fibromyalgia: An Explanatory, Randomized, Double-Blind Crossover Study

Background: The fibromyalgia (FM) physiopathology involves an intracortical excitability/inhibition imbalance as measured by transcranial magnetic stimulation measures (TMS). TMS measures provide an index that can help to understand how the basal neuronal plasticity state (i.e., levels of the serum neurotrophins brain-derived neurotrophic factor (BDNF) and S100-B protein) could predict the effect of therapeutic approaches on the cortical circuitries. We used an experimental paradigm to evaluate if pregabalin could be more effective than a placebo, to improve the disinhibition in the cortical circuitries in FM patients, than in healthy subjects (HS). We compared the acute intragroup effect of pregabalin with the placebo in FM patients and healthy subjects (HS) on the current silent period (CSP) and short intracortical inhibition (SICI), which were the primary outcomes. Pain scores and the pain pressure threshold (PPT) were secondary outcomes.

Methods: This study included 27 women (17 FM and 10 HS), with ages ranging from 19 to 65 years. In a blinded, placebo-controlled clinical trial, participants were randomized to receive, in a cross-over manner, oral pregabalin of 150 mg or a placebo. The cortical excitability pain measures were assessed before and 90 min after receiving the medication.

Results: A generalized estimating equation (GEE) model revealed that in FM, pregabalin increased the CSP by 14.34% [confidence interval (CI) 95%; 4.02 to 21.63] and the placebo reduced the CSP by 1.58% (CI 95%; −57 to 25.9) (P = 0.00). Pregabalin reduced the SICI by 8.82% (CI 95%, −26 to 46.00) and the placebo increased it by 19.56% (CI 95%; 8.10 to 59.45; P = 0.02). Pregabalin also improved the pain measures. In the treatment group, the BDNF-adjusted index was positively correlated and the serum S100-B negatively correlated with the CSP, respectively. However, in the HS, pregabalin and the placebo did not induce a statistically significant effect in either intracortical excitability or pain measures.

Conclusion: These results suggest that pregabalin’s effect on cortical neural networks occurs, particularly under basal neuronal hyperexcitability, because its impact on the cortical excitability and the pain measures was observed only in the FM group. This indicates that pregabalin increased the CSP to induce inhibition in specific neural networks, while it increased the SICI to improve the excitability in other neurobiological systems. Trial registration in clinicaltrials.gov Identifier: NCT02639533.

Tolerability, pharmacokinetics, and pharmacodynamics of mirogabalin in healthy subjects: Results from phase 1 studies

Three phase 1 pharmacokinetic (PK)/pharmacodynamics (PD) studies were conducted in healthy men and women to further characterize the safety, tolerability, and PK/PD of mirogabalin administration with or without food and to guide the dose selection and regimen for phase 2 and 3 clinical development. The 3 studies included 2 randomized, double-blind, placebo-controlled, single- and multiple-ascending-dose studies, and 1 open-label, crossover study to evaluate the PK of mirogabalin administered under fasting and fed (high-fat meal) conditions. Forty-eight and 47 healthy volunteers completed the single- and multiple-dose studies, respectively. Thirty subjects were enrolled and completed the food effect study. Mirogabalin was well tolerated in the fed and fasted states. The most frequent treatment-emergent adverse events (TEAEs)-dizziness and somnolence-were expected based on mirogabalin's mechanism of action. Subjects receiving the highest mirogabalin doses (50 and 75 mg single dose) showed greater dizziness and sedation and higher rates of TEAEs than subjects receiving 3-30 mg. After oral administration, mirogabalin was rapidly absorbed (time to maximum concentration, ∼1 hour) and eliminated through urine unchanged (61%-72% urinary excretion). Exposure increased in a dose-proportional manner after single or multiple mirogabalin doses. No significant accumulation occurred with multiple doses over 14 days. After single doses of mirogabalin (15 mg), the bioavailability was considered equivalent in the fed and fasted states, indicating that mirogabalin can be taken without food restrictions. Based on these data, mirogabalin 15 mg twice daily was selected as the highest target dose for further clinical development.

Lack of a Clinically Significant Pharmacokinetic Interaction Between Pregabalin and Thioctic Acid in Healthy Volunteers

PURPOSE

Pregabalin and thioctic acid are likely to be used concomitantly for the treatment of painful diabetic neuropathy. In this study, the pharmacokinetic interaction between pregabalin and thioctic acid was investigated at steady state.

METHODS

A randomized, open-label, 6-sequence, 3-period, 3-treatment crossover study was conducted in 42 healthy male volunteers. The volunteers randomly received pregabalin 300 mg BID for 6 times, thioctic acid 600 mg once daily for 3 times, or the combination of pregabalin and thioctic acid. Serial blood samples were collected up to 24 hours after the last dosing in each period. Pharmacokinetic parameters were calculated by using noncompartmental analysis methods.

FINDINGS

The mean concentration-time curves were similar between each drug alone and in combination with the other drug. The 90% CIs of the geometric mean ratios with and without the co-administered drug for C_max at steady state and AUC during the dosing interval were well within the conventional bioequivalence range of 0.8 to 1.25, except for C_max at steady state for thioctic acid, which barely exceeded only the lower bound (0.78-1.15). Co-administered pregabalin and thioctic acid was well tolerated.

IMPLICATIONS

Repeatedly administered pregabalin and thioctic acid do not interact pharmacokinetically. This study suggests that the combination of pregabalin and thioctic acid can safely be administered concomitantly without dose adjustment. ClinicalTrials.gov identifier: NCT01808300.