Pharmacology of oral combination analgesics: rational therapy for pain

Evaluating potential unexpected adverse events and mortality after oral analgesics administration in fracture care-a cohort study

INTRODUCTION

Analgesic selection per individual's tolerance is essential to avoid risks. The study evaluated current oral analgesic prescription practice, analgesic adverse effects-related factors, unexpected events, and mortality post-fracture surgery.

RESEARCH DESIGN AND METHODS

The present prospective cohort study from June 2022 to July 2023 enrolled a total of 198 proximal femoral, ankle, and hindfoot trauma fracture patients. Stratification was done for oral analgesics prescribed at hospital discharge and 1 week with their accompanying toxicity assessed for 2 weeks. Analyzed Kaplan-Meier curve and the absolute risk for possible analgesics-related deaths.

RESULTS

Following oral analgesic administration, 122 (62%) patients experienced adverse events. In seven expiries, five were possibly due to acetaminophen added tramadol combined with any of pregabalin, diclofenac, etoricoxib, or gabapentin (absolute risk 2.5%, 97.5% proportion 2 weeks survival). Three (2% of 122) patients taking acetaminophen added tramadol or diclofenac experienced unexpected serious adverse events. Elderly diabetic and hypertensive hip fracture patients expired or experienced unexpected events.

CONCLUSION

Data suggest that oral acetaminophen added tramadol combined with any of pregabalin, diclofenac, etoricoxib, or gabapentin might increase the death risk or unexpected serious adverse events in elderly diabetic and hypertensives suffering from intertrochanteric/femoral neck fracture. Safe analgesic selection is necessitated for at-risk patients.

Ibuprofen/acetaminophen fixed-dose combination as an alternative to opioids in management of common pain types

Opioids are frequently used first line to manage acute pain in a variety of settings; however, the use of nonprescription analgesics for acute pain is recognized by experts as a practical and effective opioid-sparing strategy. Variations in dosages and formulations and a lack of standardization in reporting clinical data hinder the awareness of nonprescription treatments and recommendation of their use before opioids and other prescription options. A fixed-dose combination (FDC) of two common nonprescription analgesics, ibuprofen (IBU) and acetaminophen (APAP), is an appealing alternative to opioids in acute pain settings with a range of potential benefits. This narrative review evaluates the evidence in support of IBU/APAP FDCs containing IBU (≤1200 mg/day) and APAP (≤4000 mg/day), the nonprescription maximum daily doses in Canada and the United States, as alternatives to opioids and as a means to reduce the need for rescue opioid medication in acute pain management. A literature search was performed to identify clinical studies that directly compared IBU/APAP FDCs with opioids or nonopioids and measured the need for opioid rescue therapy in acute pain. Across studies, IBU/APAP FDCs consistently demonstrated pain relief similar to or better than opioid and nonopioid comparators and reliably reduced the use of rescue opioids with fewer adverse events. Based on these data, healthcare clinicians should consider FDC nonprescription analgesics as a potential first-line option for the management of acute pain.

Wilderness Medical Society Clinical Practice Guidelines for the Treatment of Acute Pain in Austere Environments: 2024 Update

The Wilderness Medical Society (WMS) convened an expert panel to develop evidence-based guidelines for the management of pain in austere environments. Recommendations are graded based on the quality of supporting evidence as defined by criteria put forth by the American College of Chest Physicians. This is an update of the 2014 version of the "WMS Practice Guidelines for the Treatment of Acute Pain in Remote Environments" published in Wilderness & Environmental Medicine 2014; 25:41-49.

Simultaneous determination of tramadol and paracetamol in human plasma using LC-MS/MS and application in bioequivalence study of -fixed-dose combination

The study aimed to develop a sensitive and high-throughput liquid chromatography coupled with tandem mass spectrometry method to quantify concentrations of tramadol and paracetamol simultaneously in human plasma. Sample preparation involved single-step protein precipitation using methanol and two deuterated internal standards, tramadol D6 and paracetamol D4. Agilent Poroshell 120 EC-C18 (100 × 2.1 mm, 2.1 µm) analytical column was employed to achieve chromatographic separation. Detection was in positive ion multiple reaction monitoring mode. A tailing factor (Tf) of <1.2, separation factor (K prime) of >1.5 from the column dead time and signal-to-noise (S/N) ratio >10, were obtained for analytes and internal standards. The standard curve was linear over the concentration range of 2.5-500.00 ng/mL for tramadol and 0.025-20.00 μg/mL for paracetamol. A small injection volume of 1 µL, low flow rate of 440 µL/min and short analysis time of 3.5 min reduced the solvent consumption, analysis cost and system contamination. The results of method validation parameters fulfilled the acceptance criteria of bioanalytical guidelines. The method was successfully applied to a bioequivalence study of fixed-dose combination products of tramadol and paracetamol in Malaysian healthy subjects.

Association Between Postoperative Methocarbamol and Postoperative Pain Opioid Dose Requirements: A Retrospective Cohort Study

OBJECTIVES

We tested the hypothesis that patients who received methocarbamol postoperatively experience less severe pain and require smaller doses of opioids than those who did not receive methocarbamol.

MATERIALS AND METHODS

This is a retrospective cohort study of patients undergoing surgery involving the musculoskeletal system. Of 9089 patients, 704 received methocarbamol during 48 hours postoperatively, while 8385 did not receive methocarbamol. The patients who received methocarbamol postoperatively and the patients who did not receive methocarbamol were compared on the time-weighted average (TWA) pain score and opioid dose requirements in morphine milligram equivalents (MME) during the first 48 hours postoperatively, using propensity score-weighted regression models to adjusting for preoperative and intraoperative covariates.

RESULTS

Postoperative 48-hour TWA pain scores were 5.5±1.7 (mean±SD), and 4.3±2.1 for methocarbamol and non-methocarbamol patients. Postoperative 48-hour opioid dose requirements in MME were 276 [170-347] (median [interquartile range (IQR)]) mg, and 190 [60-248] mg for methocarbamol and non-methocarbamol patients. In propensity score-weighted regression models, receiving methocarbamol postoperatively was associated with 0.97-point higher postoperative TWA pain score (95% CI, 0.83-1.11; P <0.001), and 93.6-MME higher postoperative opioid dose requirements (95% CI, 79.9 to 107.4; P <0.001), compared with not receiving methocarbamol postoperatively.

DISCUSSION

Postoperative methocarbamol was associated with significantly higher acute postoperative pain burden and opioid dose requirements. Although the results of the study are influenced by residual confounding, they suggest a limited-if any-benefit of methocarbamol as an adjunct of postoperative pain management.

Pregabalin-Tolperisone Combination to Treat Neuropathic Pain: Improved Analgesia and Reduced Side Effects in Rats

The current treatment of neuropathic pain (NP) is unsatisfactory; therefore, effective novel agents or combination-based analgesic therapies are needed. Herein, oral tolperisone, pregabalin, and duloxetine were tested for their antinociceptive effect against rat partial sciatic nerve ligation (pSNL)-induced tactile allodynia described by a decrease in the paw withdrawal threshold (PWT) measured by a dynamic plantar aesthesiometer. On day 7 after the operation, PWTs were assessed at 60, 120, and 180 min post-treatment. Chronic treatment was continued for 2 weeks, and again, PWTs were measured on day 14 and 21. None of the test compounds produced an acute antiallodynic effect. In contrast, after chronic treatment, tolperisone and pregabalin alleviated allodynia. In other experiments, on day 14, the acute antiallodynic effect of the tolperisone/pregabalin or duloxetine combination was measured. As a novel finding, a single dose of the tolperisone/pregabalin combination could remarkably alleviate allodynia acutely. It also restored the neuropathy-induced elevated CSF glutamate content. Furthermore, the combination is devoid of adverse effects related to motor and gastrointestinal transit functions. Tolperisone and pregabalin target voltage-gated sodium and calcium channels, respectively. The dual blockade effect of the combination might explain its advantageous acute analgesic effect in the present work.

Acute Traumatic Pain in the Emergency Department

Trauma is a major cause of mortality throughout the world. Traumatic pain—acute, sudden, or chronic—is defined as “an unpleasant sensory and emotional experience associated with actual or potential tissue damage”. Patients’ perceptions of pain assessment and management have become an important criterion and relevant outcome measure for healthcare institutions. Several studies show that 60–70% of ER patients experience pain, and more than half of them express a feeling of sorrow, which can be moderate or severe, at triage. The few studies that have analyzed how pain is assessed and managed in these departments agree that approximately 70% of patients receive no analgesia or receive it with remarkable delay. Specifically, less than half of the patients receive treatment for pain during admission and 60% of discharged patients have higher intensity pain than at admission. Trauma patients are also the ones who most commonly report low satisfaction with pain management. Associated with this lack of satisfaction, we can describe the poor use of tools for measuring and recording pain, poor communication among caregivers, inadequate training in pain assessment and management, and widespread misconceptions among nurses about the reliability of patients’ estimation of pain. The aim of this article is to review the scientific literature to explore the methodologies of pain management in trauma patients attending the emergency room and analyzing their weaknesses as a starting point to improve the approach to this, unfortunately too often, underestimated issue. A literature search was performed using the major databases to identify relevant studies in indexed scientific journals. The literature showed that the multimodal approach in trauma patients is the best approach to pain management. It is becoming increasingly crucial to manage the patient on multiple fronts. Drugs acting on different pathways can be administered together at lower doses, minimizing risks. Every emergency department must have staff trained in the assessment and immediate management of pain symptoms as this allows the reduction of mortality and morbidity and shortens hospital stays, contributing to early mobilization, reduced hospital costs, and enhanced patient satisfaction and quality of life.

An Updated Review on the Metabolite (AM404)-Mediated Central Mechanism of Action of Paracetamol (Acetaminophen): Experimental Evidence and Potential Clinical Impact

Paracetamol remains the recommended first-line option for mild-to-moderate acute pain in general population and particularly in vulnerable populations. Despite its wide use, debate exists regarding the analgesic mechanism of action (MoA) of paracetamol. A growing body of evidence challenged the notion that paracetamol exerts its analgesic effect through cyclooxygenase (COX)-dependent inhibitory effect. It is now more evident that paracetamol analgesia has multiple pathways and is mediated by the formation of the bioactive AM404 metabolite in the central nervous system (CNS). AM404 is a potent activator of TRPV₁, a major contributor to neuronal response to pain in the brain and dorsal horn. In the periaqueductal grey, the bioactive metabolite AM404 activated the TRPV₁ channel-mGlu5 receptor-PLC-DAGL-CB1 receptor signaling cascade. The present article provides a comprehensive literature review of the centrally located, COX-independent, analgesic MoA of paracetamol and relates how the current experimental evidence can be translated into clinical practice. The evidence discussed in this review established paracetamol as a central, COX-independent, antinociceptive medication that has a distinct MoA from non-steroidal anti-inflammatory drugs (NSAIDs) and a more tolerable safety profile. With the establishment of the central MoA of paracetamol, we believe that paracetamol remains the preferred first-line option for mild-to-moderate acute pain for healthy adults, children, and patients with health concerns. However, safety concerns remain with the high dose of paracetamol due to the NAPQI-mediated liver necrosis. Centrally acting paracetamol/p-aminophenol derivatives could potentiate the analgesic effect of paracetamol without increasing the risk of hepatoxicity. Moreover, the specific central MoA of paracetamol allows its combination with other analgesics, including NSAIDs, with a different MoA. Future experiments to better explain the central actions of paracetamol could pave the way for discovering new central analgesics with a better benefit-to-risk ratio.

Fixed Dose Versus Loose Dose: Analgesic Combinations

Combinations of drugs may be fixed (two or more entities in a single product) or loose (two or more agents taken together but as individual agents) to help address multimechanistic pain. The use of opioids plus nonopioids can result in lower opioid consumption without sacrificing analgesic benefits. Drug combinations may offer additive or synergistic benefits. A variety of fixed-dose combination products are available on the market such as diclofenac plus thiocolchicoside, acetaminophen and caffeine, acetaminophen and opioid, ibuprofen and acetaminophen, tramadol and acetaminophen, and others. Fixed-dose combination products offer predictable pharmacokinetics and pharmacodynamics, known adverse events, and can reduce the pill burden. However, they are limited to certain drug combinations and doses; loose dosing allows prescribers the versatility to meet individual patient requirements as well as the ability to titrate as needed. Not all drug combinations offer synergistic benefits, which depend on the drugs and their doses. Certain drugs offer dual mechanisms of action in a single molecule, such as tapentadol, and these may further be used in combination with other analgesics. New technology allows for co-crystal productions of analgesic agents which may further improve drug characteristics, such as bioavailability. Combination analgesics are important additions to the analgesic armamentarium and may offer important benefits at lower doses than monotherapy.

Evaluation of Phytochemistry and Pharmacological Properties of Alnus nitida

In the current study, the anti-inflammatory and analgesic potential of Alnus nitida (leaves and fruits) was evaluated in the Sprague-Dawley rat. Traditionally, A. nitida was used for the treatment of inflammatory ailments. However, A. nitida leaves and fruits have not been yet reported regarding any potential medicinal effects. Leaves/fruits of A. nitida were extracted with methanol and fractionated to attain n-hexane, chloroform, ethyl acetate and aqueous fractions. These extracts were then evaluated for in vivo analgesic and anti-inflammatory potential. For in vivo anti-inflammatory activity, carrageenan-induced paw edema assay, Freunds’ complete adjuvant-induced edema, xylene-induced ear edema and histamine-induced paw edema models were used in rats, which showed significant (p < 0.01) reduction (70−80%) in edema in comparison of inflammatory controls. On other hand, for the analgesic assessment, hot plate assay and acetic acid-induced writhing tests were used, which showed a significant (p < 0.01) rise in latency time (40−60%) as compared with pain-induced controls. These results were comparable with standard drugs in a concentration-dependent manner and no mortality or toxicity was observed during all experiments. Then, for the identification of chemical constituents gas chromatography−mass spectrometry (GC-MS) analysis was performed, which indicated the presence of neophytadiene, 3,7,11,15-Tetramethyl-2-hexadecen-1-ol, phytol and vitamin E, justifying the use of A. nitida to treat inflammatory disorders.

Pharmaceutical care for patients with headache

INTRODUCTION

Headache cephalalgia is the condition in which individuals feel pain in different parts of the head. It is one of the most common disorders believed to be amenable to self-treatment. The pharmacist can provide significant support to patients.

Pharmacotherapeutic management of trigeminal neuropathic pain: an update

INTRODUCTION

Guidelines recommend a number of pharmacotherapeutic options used as monotherapy or in combination with others for treating the pain of trigeminal neuropathy.

AREAS COVERED

The authors examine the pharmacotherapeutic options for treating trigeminal neuralgia and supporting evidence in the literature. Guidelines reported the most effective treatment for trigeminal neuropathy, in particular trigeminal neuralgia, appears to be carbamazepine or oxcabazepine, but side effects can be treatment limiting. Lamotrigine and gabapentin are also recommended in guidance. In real-world clinical practice, baclofen, cannabinoids, eslicarbazepine, levetiracetam, brivaracetam, lidocaine, misoprostol, opioids, phenytoin, fosphenytoin, pimozide, sodium valproate, sumatriptan, tizanidine, tocainide, tricyclic antidepressants, and vixotrigine are sometimes used, either as monotherapy or in combination. The relatively small patient population has limited the number of large-scale studies and there is limited evidence on which to base prescribing choices.

EXPERT OPINION

While there is no optimal pharmacotherapy for treating trigeminal neuropathy, advancements in our understanding of the underlying mechanisms of this condition and drug development indicate promise for NaV inhibitors, despite the fact that not all patients respond to them and they may have potentially treatment-limiting side effects. Nevertheless, better understanding of NaV channels may be important avenues for future drug development for trigeminal neuropathy.

Clinical effect of preoperative intravenous non-steroidal anti-inflammatory drugs on relief of postoperative pain in patients after laparoscopic cholecystectomy: Intravenous ibuprofen vs. intravenous ketorolac

Backgrounds/Aims

Postoperative pain management is a key to enhanced recovery after surgery. The aim of this study was to evaluate clinical effect of preoperative intravenous (IV) non-steroidal anti-inflammatory drugs (NSAIDs) on relief of postoperative pain in patients after laparoscopic cholecystectomy.

Methods

This single center, retrospective study was conducted between September 2019 and May 2020. A total of 163 patients were divided into two groups: Ibuprofen group (preoperative IV ibuprofen, n = 77) and Ketorolac group (preoperative IV ketorolac, n = 86). The primary outcome was postoperative pain score measured immediately in the recovery room.

Results

There was no difference in demographic characteristics between the two groups of patients. Postoperative pain score measured immediately in the recovery room was significantly higher in the Ibuprofen group than in the Ketorolac group (mean value: 5.09 vs. 4.61; p = 0.027). The number of patients who needed analgesics immediately in the recovery room was also higher in the Ibuprofen group than in the Ketorolac group (28 [36.4%] vs. 18 [20.9%]; p = 0.036).

Conclusions

In this study, preoperative IV injection with ketorolac reduced postoperative pain and analgesic requirement in the recovery room more effectively than that with ibuprofen. However, both showed similar effects on peak pain and pain at discharge. Numbers of patients requiring additional analgesics were also similar between the two groups.

What Is New in the Clinical Management of Low Back Pain: A Narrative Review

Low back pain (LBP) is a prevalent condition associated with disability. Treating patients with LBP becomes further complicated by the potential presence of underlying conditions, such as cancer or traumatic injury, or biopsychosocial aspects. LBP usually has a neuropathic component that must be assessed and treated appropriately. Pharmacological management of LBP requires a thorough knowledge of the available agents and the mechanisms of the LBP. Although there are effective pharmacological treatments for LBP, it is important to consider safety issues. Fixed-dose combination products may be helpful, as they can reduce opioid consumption without sacrificing analgesic benefits. Neuromodulation is an important and sometimes overlooked treatment option for LBP and may be appropriate for chronic LBP requiring long-term treatment. Imaging studies support neuroplastic changes in the brain as a result of neuromodulation. Interventional approaches to chronic LBP are numerous and must be appropriately selected based on the individual patient. Evidence in support of epidural injections for LBP is strong for short-term pain control but moderate to limited for long-term relief. Rehabilitation for LBP can be an important element of long-term care, and new forms of rehabilitation programs are being developed using telemedicine. A variety of new and established treatments are available for patients with LBP, and clinicians and patients may benefit from emerging new treatment modalities.

Delivery of Multimodal Analgesia to Effectively Treat Acute Pain: A Review From Roma Pain Days

It is crucial that acute pain be promptly and adequately treated in order to prevent it from transitioning to chronic pain, a devastating and sometimes permanent condition that is challenging to treat and associated with disability, reduced quality of life, and depression. Guidelines for the treatment of acute low-back pain (LBP) are predicated on assumptions that all acute LBP is benign, temporary, and traditionally treated with a “wait and see” approach. LBP is far from a monolithic condition: etiology, the presence of underlying conditions, mental health status, social situation, patient’s age and occupation, and comorbidities all present different risk factors for chronic LBP that should be considered in treating acute LBP or other forms of acute pain. A multimodal approach to acute pain has been shown to be safe and effective. In particular, the combination product of oral dexketoprofen and tramadol has been shown effective in controlling acute pain, which spares the use of opioids and is well tolerated. Chronic pain must be viewed as a global health crisis, and the timely and adequate control of acute painful conditions is a good strategy to reduce its prevalence. Experts at Roma Pain Days discussed this important topic which is the foundation of this review.

Pharmacological Treatment for Acute Traumatic Musculoskeletal Pain in Athletes

Pain management is a crucial issue for athletes who train and compete at the highest performance levels. There are still evidence gaps for the use of analgesics for sports injuries despite the growing interest in training and competition settings. However, high-quality research is needed to determine the most appropriate and optimal timing and formulations in non-steroidal anti-inflammatory drug and opioid management, particularly given the strictness of anti-doping regulations. Indeed, the role of pharmacological therapy in reducing acute traumatic pain in athletes should still be addressed to minimize the timing of return to sport. Therefore, the aim of this comprehensive review was to summarize the current evidence about pain management in the setting of acute injury in elite athletes, providing the most informed strategy for pain relief and performance recovery.

Antinociceptive Synergism of Pomegranate Peel Extract and Acetylsalicylic Acid in an Animal Pain Model

Several modern drugs, which are derived from traditional herbal medicine are used in contemporary pharmacotherapy. Currently, the study of drug-plant interactions in pain has increased in recent years, looking for greater efficacy of the drug and reduce side effects. The antinociception induced by intragastric co-administration of the combination of pomegranate peel extract (PoPEx) and acetylsalicylic acid (ASA) was assessed using the isobolographic analysis in formalin test (nociceptive and inflammatory pain). The effective dose that produced 30% of antinociception (ED30) was calculated for both drugs from the logarithmic dose-response curves, subsequently generating a curve with the combination on fixed proportions (1:1) of PoPEx and ASA. Through isobolographic analysis, this experimental ED30 was compared with the calculated theoretical additive ED30. The result was a synergistic interaction, the experimental ED30 was significantly smaller (p < 0.05) than the theoretical ED30. The antinociceptive mechanism of the PoPEx-ASA combination involves the l-Arginine/NO/cGMP pathway, antioxidant capacity, and high content of total phenols. These findings suggest that an interaction between PoPEx and ASA could be a novel treatment for inflammatory and nociceptive pain, also diminish the secondary reactions of ASA.

Clinical and pharmacological approaches to the choice of a drug for a tension-type headache relief

The article goes to describe clinical and pharmacological approaches to choosing a drug with an optimal efficacy/safety profile, providing the necessary analgesic effect in tension-type headache. TRPV1 brain receptors are considered the main action point of the mediator. Aim. The purpose of this study is a comparative analysis of the pharmacodynamic and pharmacokinetic parameters of ibuprofen and paracetamol as a part of fixed dose combination and as monotherapy in tension type headaches. Materials and methods. Comparative dissolution kinetics test; Comparative analysis of pharmacokinetic parameters using the PubMed/MEDLINE database. Results. The median Tmax of ibuprofen as a part of a fixed-dose combination and as a monotherapy is 75 minutes. The median Tmax of paracetamol is 30 min when taken in a fixed dose combination and 40 min as a monotherapy. In patients who received the fixed dose combination, the concentration of ibuprofen in the blood plasma after 10 minutes 6.64 g/ml-1; after 20 minutes 16.81 g/ml-1, while when taken in the same dose in as a monotherapy, respectively, 0.58 and 9.00 g/ml-1. The mean plasma concentrations of paracetamol after 10 and 20 minutes in patients receiving the fixed combination were 5.43 and 14.54 g/ml-1, respectively, compared with 0.33 and 9.19 g/ml-1 for paracetamol as monotherapy. dissolution kinetics test of the Paracytolgin: after 5 minutes, 20% of paracetamol passed into the solution in a system with a pH of 1.2; in a system with a pH of 4.5 36.4%; in a system with a pH of 6.8 33.5%; after 10 minutes, respectively 68.5, 98.0 and 89.6%. After 15 minutes, almost complete dissolution was noted in all systems: 98.5, 98.8 and 100.5%, respectively. Discussion. The combination of ibuprofen and paracetamol makes it possible to enhance the analgesic effect as a result of additive action by the help of central mechanisms. The fixed dose combination of ibuprofen and paracetamol significantly increases the rate of absorption of paracetamol, which has potential therapeutic benefits in terms of a faster analgesias onset. Conclusion. The fixed dose combination of ibuprofen and paracetamol provides faster and long-term anaesthesia with a comparatively lower dosage of each analgesic.

Abuse Deterrent Formulations in Constraining the Abuse Potential of Prescription Medicines: A Myth or Truth

BACKGROUND

Diverse pain killers used for the management of varied categories of pain are being misused in order to have extreme pleasant effect by a large number of populations. To overcome the misuse of prescription drugs, regulatory bodies have given stress on development of abuse resistance.

METHODS

We studied numerous literatures: (1) Research and review papers including the guidelines for pain management, abuse, and abuse deterrence; (2) Description and categorization of pain along with the management approaches; (3) advantages and disadvantages of the abuse deterrent formulations were described.

RESULTS

Abuse deterrent formulations are the contemporary remedial treatment for pain with reduced prospects of being abused. But these comprise the huge expense in contrast to the generic drugs as well as the non-deterrent branded equivalents.

CONCLUSION

Many challenges are faced throughout the development of abuse deterrent formulations. These formulations displayed substantial drop in abuse incidences but it may lead to other modes of abuse which may prove more harmful for the users.

Clinical Consumption of Compound Opioid Analgesics in China: A Retrospective Analysis of National Data 2015-2018

Compound opioid analgesics (COA) are widely used for cancer pain relief, but few studies investigated the use of that. We aimed to report the characteristics and trend of COA consumption in different regions and health facilities in China. The procurement data of two types of COA, compound codeine phosphate (CCP) and oxycodone and acetaminophen (OAA), in all medical institutions of 20 provinces from 2015 to 2018 were used. Data were presented as defined daily dose for statistical purpose (SDDD) and expenditures per million inhabitants per day. The annual consumption of COA and ratio of two combinations were compared among regions and institutions. We found, during 2015-2018, COA consumption increased at an average rate of 7.32% in SDDD and 19.19% in expenditures, while OAA accounted for most of the consumption. Highest COA consumption appeared in Northern China, with 121.72 SDDD and 1689.87 RMB (2015), whereas the lowest COA consumption was only 11.28 SDDD appearing in Southern China. The ratio of OAA and CCP (in SDDD) was highest in Southern China (53.14 in 2018), whereas lowest in West North (0.37 in 2018). In terms of institutions, tertiary had the highest COA consumption, with 16.74 SDDD and 292.73 RMB (2018). The SDDD of OAA was 27.44 times of that of CCP in tertiary, while it was only 0.11 in primary. Overall, COA consumption is on an upward trend and different among regions and health institutions in either amount or types of COA. These findings call for establishment of COA management regulations.

Monoacylglycerol Lipase Inhibition Using JZL184 Attenuates Paw Inflammation and Functional Deficits in a Mouse Model of Inflammatory Arthritis

Background: Patients with rheumatoid arthritis (RA) experience joint swelling and cartilage destruction resulting in chronic pain, functional disability, and compromised joint function. Current RA treatments, including glucocorticoid receptor agonists, produce adverse side effects and lack prolonged treatment efficacy. Cannabinoids (i.e., cannabis-like signaling molecules) exert anti-inflammatory and analgesic effects with limited side effects compared to traditional immunosuppressants, making them excellent targets for the development of new arthritic therapeutics. Monoacylglycerol lipase (MAGL) inhibition reduces inflammation in mouse models of acute inflammation, through cannabinoid receptor dependent and independent pathways. The current study investigated the efficacy of inhibiting synthetic and catabolic enzymes that regulate the endocannabinoid 2-arachidonoylglycerol (2-AG) in blocking paw inflammation, pain-related behaviors, and functional loss caused by collagen-induced arthritis (CIA). Methods: Male DB1A mice subjected to CIA were administered the glucocorticoid agonist dexamethasone (DEX), MAGL inhibitor JZL184 (8 or 40 mg/kg, s.c.), alone or in combination, or diacylglycerol lipase β (DAGLβ) inhibitor KT109 (40 mg/kg, s.c.). CIA-induced deficits were assayed by arthritic clinical scoring, paw thickness measurements, and behavioral tests of pain and paw function. Results: DEX or dual administration with JZL184 reduced paw thickness and clinical scores, and JZL184 dose-dependently attenuated grip strength and balance beam deficits caused by CIA. Traditional measures of pain-induced behaviors (hyperalgesia and allodynia) were inconsistent. The antiarthritic effects of JZL184 (40 mg/kg) were largely blocked by coadministration of the CB₂ antagonist SR144528, and the DAGLβ inhibitor KT109 had no effect on CIA, indicating that these effects likely occurred through CB₂ activation. Conclusions: MAGL inhibition reduced paw inflammation and pain-depressed behavioral signs of arthritis, likely through an endocannabinoid mechanism requiring CB₂. These data support the development of MAGL as a target for therapeutic treatment of inflammatory arthritis.

Effectiveness of ibuprofen plus paracetamol combination on persistence of acute musculoskeletal disorders in primary care patients

Background General practitioners often deal with patients suffering acute musculoskeletal disorders. Paracetamol, non-steroidal anti-inflammatory drugs, and opioids are the most prescribed medications, according to pain intensity and patient's features. Combinations of different analgesics can be adopted to enhance pain relief, but only one fixed-dose combination has been recently launched to treat acute musculoskeletal pain. Objective This study aimed to investigate the effectiveness of ibuprofen plus paracetamol (fixed-dose) combination compared to other analgesics in preventing musculoskeletal pain persistence. Setting Italian outpatients' data extracted from a national general practice database. Method A retrospective cohort study was conducted on the Health Search Database. Patients prescribed with analgesics for acute musculoskeletal painful conditions were considered (i.e., non-chronic painful conditions, identified using a query validated by two expert General Practitioners (GPs)). For each patient, the first prescription of an analgesic was defined as index date. A new GP's visit related to musculoskeletal disorders in the first 3 months following the index date was defined as "pain persistence". Main outcome measure Risk of pain persistence among users of the ibuprofen plus paracetamol combination compared to other systemic analgesics. Results Overall, 102,216 patients were treated with systemic analgesics for acute musculoskeletal disorders. Most patients were middle-aged or elderly women. 939 (0.92%) patients were prescribed with the fixed-dose ibuprofen plus paracetamol combination for a mean duration of 7.23 ± 2.68 days, mainly for low back pain and cervicalgia. Musculoskeletal pain persistence was found in 22,125 (21.65%) patients. Compared to other systemic analgesics, the ibuprofen plus paracetamol combination resulted significantly more effective in preventing pain persistence (adjusted hazard ratio 0.72, 95% confidence interval 0.61-0.85). Conclusion These findings suggest that the fixed-dose ibuprofen plus paracetamol combination might be effective in controlling musculoskeletal pain persistence.

Pain Chemogenomics Knowledgebase (Pain-CKB) for Systems Pharmacology Target Mapping and Physiologically Based Pharmacokinetic Modeling Investigation of Opioid Drug-Drug Interactions

More than 50 million adults in America suffer from chronic pain. Opioids are commonly prescribed for their effectiveness in relieving many types of pain. However, excessive prescribing of opioids can lead to abuse, addiction, and death. Non-steroidal anti-inflammatory drugs (NSAIDs), another major class of analgesic, also have many problematic side effects including headache, dizziness, vomiting, diarrhea, nausea, constipation, reduced appetite, and drowsiness. There is an urgent need for the understanding of molecular mechanisms that underlie drug abuse and addiction to aid in the design of new preventive or therapeutic agents for pain management. To facilitate pain related small-molecule signaling pathway studies and the prediction of potential therapeutic target(s) for the treatment of pain, we have constructed a comprehensive platform of a pain domain-specific chemogenomics knowledgebase (Pain-CKB) with integrated data mining computing tools. Our new computing platform describes the chemical molecules, genes, proteins, and signaling pathways involved in pain regulation. Pain-CKB is implemented with a friendly user interface for the prediction of the relevant protein targets and analysis and visualization of the outputs, including HTDocking, TargetHunter, BBB predictor, and Spider Plot. Combining these with other novel tools, we performed three case studies to systematically demonstrate how further studies can be conducted based on the data generated from Pain-CKB and its algorithms and tools. First, systems pharmacology target mapping was carried out for four FDA approved analgesics in order to identify the known target and predict off-target interactions. Subsequently, the target mapping outcomes were applied to build physiologically based pharmacokinetic (PBPK) models for acetaminophen and fentanyl to explore the drug-drug interaction (DDI) between this pair of drugs. Finally, pharmaco-analytics was conducted to explore the detailed interaction pattern of acetaminophen reactive metabolite and its hepatotoxicity target, thioredoxin reductase.

Real-World Evidence in Prescription Medication Use Among U.S. Adults with Neck Pain

Introduction

Neck pain is a common condition that leads to serious pain, disability, and increased healthcare costs worldwide. Pharmacotherapy is one of the most common strategies to reduce neck pain in patients. The aim of this study was to analyze the real-world pattern of drugs prescribed for patients with neck pain in the USA.

Methods

Data on individuals who reported current neck pain in the 2009−2010 US National Health and Nutrition Examination Survey (NHANES) and with a history of persistent pain for at least 6 weeks or 3 months were extracted from the NHANES database. Those included in the study were divided into three groups based on the duration of pain: the without neck pain group (Group A); subacute group (Group B) with a history of 6 weeks of neck pain; and the chronic neck pain group (Group C) with a history of 3 months of neck pain. The use and duration of medication prescribed for Group A, B, and C patients were compared.

Results

The analysis revealed that opioid use was significantly more prevalent in the subacute and chronic neck pain group than in the without neck pain group (Group A) (adjusted odds ratio [aOR] 4.20, 95% confidence interval [CI] 2.07–8.52 and aOR 7.00, 95% CI 4.32–11.33, respectively). The factors strongly associated with higher opioid use included older age, low education level, and low family income. In the chronic neck group, opioids, followed in decreasing order of frequency by acetaminophen and nonsteroidal anti-infammatory drugs, were the most common analgesics used in combination with other analgesics.

Conclusion

Our analysis of the data shows that the long-term excessive use of opioids and the underutilization of other analgesics are two major issues in the treatment of neck pain in the USA. Possible improvements include improved education of patients by healthcare professionals on the use of opioids and more consideration given to non-pharmacotherapy options. Our results reveal the potential problem in pharmacotherapy choices for neck pain treatment and may help improve the current clinical practice in the USA and other countries.

Co-administration of Pregabalin and Curcumin Synergistically Decreases Pain-Like Behaviors in Acute Nociceptive Pain Murine Models

Analgesic drugs in a combination-form can achieve greater efficacy with lesser side effects compared to either drug alone. The combination of drugs acting at different targets or mechanisms of action has been recognized as an alternative approach for achieving optimal analgesia. In this study, the analgesic effects of pregabalin (30, 60, 100, 200 mg/kg), curcumin (15, 30, 60, 100, 120 mg/kg), and 1:1 fixed-dose ratio of the pregabalin-curcumin combination were assessed using two acute nociceptive pain models, the acetic acid-induced writhing and tail-flick tests in mice. The pregabalin-curcumin combination produced a dose-dependent decrease in mean of writhes and an increase in the percentage of antinociception by the acetic acid-induced writhing test. In the tail-flick test, the combination also showed an improvement in antinociception indicated by the tail-flick latency, % antinociception, and area under the curve (AUC). Isobolographic analysis of interactions demonstrated a significant synergistic interaction effect between pregabalin and curcumin in both acute nociceptive pain models with the experimental ED₅₀ below the predicted additive line and the combination index < 1. These findings demonstrate that the combination of pregabalin and curcumin exhibits a synergistic interaction in mouse models of acute nociceptive pain.

Diacerein: Recent insight into pharmacological activities and molecular pathways

Diacerein is a symptomatic slow-acting drug in osteoarthritis (SYSADOA) and the active metabolite is rhein. It is a non-steroidal anti-inflammatory drug with unique pharmacological properties as anti-oxidant and anti-apoptosis. Diacerein has recently shown to have a potential role by mediating anti-inflammatory as well as anti-oxidant and anti-apoptosis in kidney injury, diabetes mullites, and a beneficial effect on pain relief. It may have a therapeutic role in cancer, ulcerative colitis, testicular injury and cervical hyperkeratosis. Furthermore, diacerein has a valuable addition in combination therapy as a synergetic agent. This review, the first of its kind, highlights the proposed roles of diacerein in osteoarthritis and discusses recent results supporting its emerging roles with a particular focus on how these new insights may facilitate the rational development of diacerein for targeted therapies in the future.

Improved efficacy, tolerance, safety, and abuse liability profile of the combination of CR4056 and morphine over morphine alone in rodent models

BACKGROUND AND PURPOSE

Prolonged use of opioids causes analgesic tolerance and adverse effects including constipation and dependence. Compounds targeting imidazoline I2 receptors are known to potentiate opioid analgesia in rodents. We investigated whether combination with the I2 receptor ligand CR4056 could improve efficacy and safety of morphine and explored the mechanisms of the CR4056-opioid interaction.

EXPERIMENTAL APPROACH

We used the complete Freund's adjuvant (CFA) model in rats to study the effects of treatments on hyperalgesia, morphine tolerance and microglia activation as measured by immunofluorescence. Opioid-induced adverse effects were assessed in rodent models of morphine-induced constipation, sedation (open field, sedation rating scale, and rotarod), physical dependence (naloxone-induced withdrawal), and abuse (conditioned place preference-associated reward). Chemiluminescence assays tested CR4056 as allosteric modulator of μ-opioid receptors.

KEY RESULTS

CR4056 (ED50 = 4.88 mg·kg-1 ) and morphine (ED50 = 2.07 mg·kg-1 ) synergized in reducing CFA-induced hyperalgesia (ED50 = 0.52 mg·kg-1 ; 1:1 combination). Consistently, low doses of CR4056 (1 mg·kg-1 ) spared one third of the cumulative morphine dose administered during 4 days and prevented/reversed the development of tolerance to morphine anti-hyperalgesia. These opioid-sparing effects were associated with decreased activation of microglia, independent of CR4056 interactions on μ-opioid receptors. Importantly, the low doses of CR4056 and morphine that synergize in analgesia did not induce constipation, sedation, physical dependence, or place preference.

CONCLUSION AND IMPLICATIONS

We showed selective synergism between CR4056 and morphine as analgesics. Their combination showed an improved safety and abuse liability profile over morphine alone. CR4056 could be developed as an opioid-sparing drug in multimodal analgesia.

Fixed dose drug combinations - are they pharmacoeconomically sound? Findings and implications especially for lower- and middle-income countries

Introduction: There are positive aspects regarding the prescribing of fixed dose combinations (FDCs) versus prescribing the medicines separately. However, these have to be balanced against concerns including increased costs and their irrationality in some cases. Consequently, there is a need to review their value among lower- and middle-income countries (LMICs) which have the greatest prevalence of both infectious and noninfectious diseases and issues of affordability.Areas covered: Review of potential advantages, disadvantages, cost-effectiveness, and availability of FDCs in high priority disease areas in LMICs and possible initiatives to enhance the prescribing of valued FDCs and limit their use where there are concerns with their value.Expert commentary: FDCs are valued across LMICs. Advantages include potentially improved response rates, reduced adverse reactions, increased adherence rates, and reduced costs. Concerns include increased chances of drug:drug interactions, reduced effectiveness, potential for imprecise diagnoses and higher unjustified prices. Overall certain FDCs including those for malaria, tuberculosis, and hypertension are valued and listed in the country's essential medicine lists, with initiatives needed to enhance their prescribing where currently low prescribing rates. Proposed initiatives include robust clinical and economic data to address the current paucity of pharmacoeconomic data. Irrational FDCs persists in some countries which are being addressed.

Postoperative Pain Management in Emergency Surgeries: A One-year Survey on Perception and Satisfaction among Surgical Patients

Background:

Postoperative pain varies from an individual to individual. It also varies with types and extent of surgery. In general, postoperative pain is inadequately managed in most centers worldwide, especially in developing countries. Therefore, this study presents the perception and satisfaction of postoperative pain management in emergency surgeries.

Methods:

A 1-year prospective study of the 891 patients who underwent emergency general surgeries at Ahmadu Bello University Teaching Hospital, from January to December 2018 is hereby presented. Pain scores and patient's satisfaction toward postoperative pain management were considered at 8 and 24 h postoperatively through a predesigned questionnaire. Numeric Pain Rating Scale was used to determine pain intensity and the level of satisfaction following postoperative pain management. Student's t-test was used to compare the pain scores and patient's level of satisfaction of the postoperative pain management.

Results:

A total of 891 patients were recruited for this study, with a mean age of 36.4 ± 8.9 years with a male-to-female ratio of 1.3:1. Postoperative pain management satisfaction score for patients (98%) who had pain 8-h postoperative period was 4.8 ± 1.6. Similarly, 96.4% of the patients who had pain 24 h postoperatively scored 2.8 ± 1.7. Majority of the patients 481 (54%) were of the American Society of Anesthesiologist physical Class II. Most of the patients underwent general surgery using the technique of general anesthesia.

Conclusion:

This study indicated that the perception and level of patient's satisfaction regarding postoperative pain management are inadequate. The health professionals and policy makers should be aware that postoperative pain management is suboptimal, as patients still have severe postoperative pain. Therefore, the need for improved postoperative pain management.

Effects of opioid/cannabinoid mixtures on impulsivity and memory in rhesus monkeys

The opioid epidemic underscores the need for safer and more effective treatments for pain. Combining opioid receptor agonists with drugs that relieve pain through nonopioid mechanisms could be a useful strategy for reducing the dose of opioid needed to treat pain, thereby reducing risks associated with opioids alone. Opioid/cannabinoid mixtures might be useful in this context; individually, opioids and cannabinoids have modest effects on cognition, and it is important to determine whether those effects occur with mixtures. Delay discounting and delayed matching-to-sample tasks were used to examine effects of the mu-opioid receptor agonist morphine (0.32-5.6 mg/kg), the cannabinoid CB1/CB2 receptor agonist CP55940 (0.0032-0.1 mg/kg), and morphine/CP55940 mixtures on impulsivity (n = 3) and memory (n = 4) in rhesus monkeys. Alone, each drug decreased rate of responding without modifying choice in the delay-discounting task, and morphine/CP55940 mixtures reduced choice of one pellet in a delay dependent manner, with monkeys instead choosing delayed delivery of the larger number of pellets. With the exception of one dose in one monkey, accuracy in the delayed matching-to-sample task was not altered by either drug alone. Morphine/CP55940 mixtures decreased accuracy in two monkeys, but the doses in the mixture were equal to or greater than doses that decreased accuracy or response rate with either drug alone. Rate-decreasing effects of morphine/CP55940 mixtures were additive. These data support the notion that opioid/cannabinoid mixtures that might be effective for treating pain do not have greater, and might have less, adverse effects compared with larger doses of each drug alone.

Extrusion-Based 3D Printing for Pharmaceuticals: Contemporary Research and Applications

Three-dimensional printing (3DP) has a significant impact on organ transplant, cosmetic surgery, surgical planning, prosthetics and other medical fields. Recently, 3 DP attracted the attention as a promising method for the production of small-scale drug production. The knowledge expansion about the population differences in metabolism and genetics grows the need for personalised medicine substantially. In personalised medicine, the patient receives a tailored dose and the release profile is based on his pharmacokinetics data. 3 DP is expected to be one of the leading solutions for the personalisation of the drug dispensing. This technology can fabricate a drug-device with complicated geometries and fillings to obtain the needed drug release profile. The extrusionbased 3 DP is the most explored method for investigating the feasibility of the technology to produce a novel dosage form with properties that are difficult to achieve using the conventional industrial methods. Extrusionbased 3 DP is divided into two techniques, the semi-solid extrusion (SSE) and the fused deposition modeling (FDM). This review aims to explain the extrusion principles behind the two techniques and discuss their capabilities to fabricate novel dosage forms. The advantages and limitations observed through the application of SSE and FDM for fabrication of drug dosage forms were discussed in this review. Further exploration and development are required to implement this technology in the healthcare frontline for more effective and personalised treatment.

Discovery of Anticancer Clinical Candidate, Tosedostat, As an Analgesic Agent

Tosedostat is an inhibitor of aminopeptidases currently in phase II clinical trials for the treatment of blood-related cancers. In our laboratories, we have discovered that it possesses analgesic properties. Extensive in vivo pharmacological studies for the determination of antinociceptive effects of tosedostat are presented here. These studies have indicated that the observed analgesic effect of tosedostat stems from its action on the peripheral nervous system with minimal contribution from the central nervous system. Additionally, when given in combination with morphine, tosedostat exerts a synergistic analgesic effect resulting in a reduction of effective dosages required to achieve the same analgesic effect. With broad implications in addressing the opioid addiction crisis, these revelations attest to tosedostat being a highly valuable drug candidate with diverse pharmacological functions.

The analgesic interaction of tramadol and morphine in rats: An isobolographic study

In order to assess possible synergistic antinociceptive interactions, the analgesic effects of intra-peritoneal tramadol and morphine administered either separately or in combination were determined using tail-flick latency test following exposure to radiant heat in rats. Groups of eight male Sprague-Dawley rats received either tramadol (3.90, 7.00, 12.50, and 22.20 mg kg^-1) and morphine (1.26, 2.25, 4.00 and 7.10 mg kg^-1) or a combination of tramadol and morphine (4 different combinations). The baseline latency was obtained before drug injection for each rat, then at 15, 30, 45, 60 and 75 min after injection. The effective dose (ED)₅₀ for either tramadol or morphine individually was 11.70 mgkg^-1 and 2.26 mg kg^-1, respectively. Based on isobolographic analysis, the ED₅₀ values obtained by drug combination were significantly less than the calculated additive values; which indicates that the co-administration of tramadol and morphine produces synergistic antinociception in the radiant heat tail-flick assay. Combination of morphine and tramadol administered intra-peritoneally can be used for the control of acute pain in rats.

An integrated safety analysis of combined acetaminophen and ibuprofen (Maxigesic /Combogesic®) in adults

INTRODUCTION

Acetaminophen (APAP) and ibuprofen (IBP) are two analgesic compounds with a long history of use. Both are considered safe at recommended over-the-counter daily doses. Chronic use, high doses, or concomitant medication can produce safety risks for both drugs. APAP is associated with increased risk of hepatic injury, while IBP can produce gastric bleeding and thromboembolic events. Using a combination of APAP and IBP provides superior analgesia without transgressing daily dose limits of each individual drug.

METHODS

The present study aimed to determine if treatment with a fixed-dose combination (FDC) containing APAP and IBP results in any unexpected adverse events (AEs) and/or changes in the safety profiles of its two ingredients compared to monotherapy. The analysis will examine clinical safety data obtained from either single dose trials, multiple dose trials, a long-term exposure trial, and post-marketing surveillance data of APAP/IBP FDC tablets (Maxigesic®/Combogesic®, AFT Pharmaceuticals Ltd). The largest dataset was obtained by pooling the four randomized-controlled, multiple-dose clinical studies with either APAP 325 mg + IBP 97.5 mg (FDC 325/97.5, three tablets per dose) or APAP 500 mg + IBP 150 mg (FDC 500/150, two tablets per dose). At maximum doses, the two FDCs are bioequivalent, permitting the pooling of data for the analysis of safety.

RESULTS

A safety population of 922 patients who received full doses of either FDC, APAP alone, IBP alone, or placebo was compiled from the four studies. A total of 521 AEs were experienced with the incidence of FDC AEs similar to or below either monotherapy group or placebo. The FDC did not alter the incidence and percentage of the most common AEs, including gastrointestinal events and postoperative bleeding.

CONCLUSION

Overall, the FDC is well tolerated and has a strong safety profile at single and multiple doses with improved efficacy over monotherapy.

Analgesic efficacy of ketorolac associated with a tramadol/acetaminophen combination after third molar surgery - a randomized, triple-blind clinical trial

BACKGROUND

This study compared the efficacy of ketorolac alone versus its combination with tramadol/acetaminophen for pain control after mandibular third molar surgery.

MATERIAL AND METHODS

A randomized, triple-blind clinical trial was carried out with 52 patients divided into 2 groups: Group K+T+A (1 tablet of Ketorolac 10 mg plus and 1 capsule of Tramadol 37.5 mg/acetaminophen 325 mg) and Group K (1 tablet of Ketorolac 10 mg plus and 1 placebo capsule). The treatments were given 1 h before the surgery and was repeated 4 times per day, for 48 h. The difference in postoperative pain was assessed by 4 primary end-points: pain intensity (VAS 100mm, for 48 h), rescue medication, overall assessment and adverse effects.

RESULTS

Significant differences in pain intensity were observed in the different times (p < 0.05). The comparison of groups in each time showed significant differences only of 9 h, with lower level of pain intensity for group K+T+A (p = 0.005). The need of analgesics was higher in Group K (p < 0.001), the need of antiemetic were greater in Group K+T+A (p < 0.0001). No significant difference between groups were observed in overall assessment. The adverse effects was higher in Group K+T+A.

CONCLUSIONS

The current study showed that both ketorolac and the combination of ketorolac plus tramadol/acetaminophen showed good control of pain after the extraction of the lower third molars. Although the combination group showed lower pain at 9 h, the difference is small and not clinically relevant.

Pharmacokinetics and Abuse Potential of Benzhydrocodone, a Novel Prodrug of Hydrocodone, After Intranasal Administration in Recreational Drug Users

Objective

Developing an acetaminophen-free, immediate-release hydrocodone product remains an unmet medical need; however, new opioid analgesics should not introduce new abuse risks. Benzhydrocodone is a prodrug of hydrocodone that must be metabolized into hydrocodone by enzymes in the intestinal tract to optimally deliver its pharmacologic effects. This study evaluated the intranasal pharmacokinetics and abuse potential of benzhydrocodone active pharmaceutical ingredient (API) compared with hydrocodone bitartrate (HB) API.

Design

Single-center, randomized, double-blind, crossover study.

Setting

Clinical research site.

Subjects

Healthy adult, nondependent, recreational opioid users.

Methods

Subjects (N = 51 Completers) were randomized to receive 13.34 mg of intranasal benzhydrocodone API and 15.0 mg of intranasal HB API (molar-equivalent doses of hydrocodone). Blood samples were taken, and Drug Liking scores (assessed on a bipolar visual analog scale) were obtained throughout each dosing interval. Nasal irritation and safety were assessed.

Results

Peak hydrocodone plasma concentration (Cmax) was 36.0% lower, and total hydrocodone exposures (AUClast and AUCinf) were 20.3% and 19.5% lower, respectively, for benzhydrocodone API compared with HB API (P < 0.0001). All partial AUC values were lower for benzhydrocodone API, with a ≥ 75% reduction in hydrocodone exposure at all time intervals up to one hour postdose (P < 0.0001). Median Tmax of hydrocodone following benzhydrocodone API was delayed by more than one hour compared with HB. Drug Liking score, as assessed by maximal liking (Emax), was significantly lower for benzhydrocodone API vs HB API (P = 0.004), with 45% of subjects showing a ≥ 30% reduction in Drug Liking Emax.

Conclusion

Reductions in hydrocodone exposure and associated decreases in Drug Liking relative to HB suggest that the prodrug benzhydrocodone may deter intranasal abuse.

Comparing the Efficacy of IV Ibuprofen and Ketorolac in the Management of Postoperative Pain Following Arthroscopic Knee Surgery. A Randomized Double-Blind Active Comparator Pilot Study

Introduction: Acute postoperative pain following knee arthroscopy is common in orthopedic surgeries. Managing pain postoperatively combines usage of opioids and non-steroidal anti-inflammatory drugs. The aim of this clinical study was to assess the efficacy of two different analgesic treatment regimens: intravenous (IV) ibuprofen and IV ketorolac for the treatment of postoperative pain pertaining to arthroscopic knee surgery. Methods: This was a single center, randomized, double-blind, parallel, active comparator clinical pilot study. Subjects were randomized to receive either IV ibuprofen, administered as two 800 mg doses or IV ketorolac, administered as a single 30 mg dose. Subjects in the ibuprofen group received 800 mg of IV ibuprofen within 2 h prior to surgery and a repeated second dose 4 h after the initial dose if they had not been discharged. Subjects in the ketorolac group received IV ketorolac 30 mg at the end of surgery, as per the manufacturer's recommendations. Pain assessments and opioid consumption data were collected up to 24 h postoperatively. Results: Of 53 randomized subjects, 51 completed the study. There were 20 subjects in the ibuprofen group and 31 subjects in the ketorolac group. The median (IQR) visual analog scale (VAS) pain score at resting upon post-anesthesia care unit (PACU) arrival was 33 (12, 52) vs. 9 (2, 25) (p = 0.0064) for the ketorolac and ibuprofen group, respectively. The median (IQR) visual analog scale (VAS) pain score at movement upon PACU arrival was 38 (20, 61) vs. 15 (6, 31) (p = 0.0018) for the ketorolac and ibuprofen group, respectively. Median VAS pain scores during movement taken at subsequent 30 min intervals in the ibuprofen group were less than half that of those reported in the ketorolac group for up to 90 min after arriving in PACU. The median VAS pain scores at rest and movement in the course of 120 min-24 h after PACU arrival was not statistically significant in both groups. Rescue opioid medication during PACU stay was required in 55.0% (N = 11) and 83.9% (N = 26), with a mean amount of narcotic consumption (oral morphine conversion) of 5.53 ± 5.89 mg vs. 19.92 ± 15.63 mg for the ibuprofen and ketorolac group, respectively (P < 0.001). However, opioid consumption during the first 24 h after PACU discharge was not statistically significant (p-value = 0.637). The mean time to first rescue medication was 77.62 ± 33.03 and 55.78 ± 35.37 for the ibuprofen and ketorolac group, respectively (p-value = 0.0456). There were no significant differences in patient satisfaction and documented adverse events during the first 24 h. Conclusion: This pilot study showed that the use of preemptive IV ibuprofen 800 mg could be considered to reduce postoperative pain and opioid consumption. Future prospective clinical trials using similar regimens should be conducted in order to gain a better understanding of how to best provide perioperative analgesic regimens. Clinical Trial Registration: www.ClinicalTrials.gov, identifier NCT01650519.

Prescription Medication Use Among Community-Based U.S. Adults With Chronic Low Back Pain: A Cross-Sectional Population Based Study

Many classes of medications have been evaluated in chronic low back pain (cLBP), however their utilization in the community remains unclear. We examined patterns of prescription medication use among Americans with cLBP in a nationally representative, community-based sample. The Back Pain Survey was administered to a representative sample of U.S. adults aged 20 to 69 years (N = 5,103) during the 2009 to 2010 cycle of the National Health and Nutrition Examination Survey. cLBP was defined as self-reported pain in the area between the lower posterior margin of the ribcage and the horizontal gluteal fold on most days for at least 3 months (N = 700). Home-based interviews with pill bottle verification were used to capture commonly prescribed medications for chronic pain. Among the sample of U.S. adults with cLBP aged 20 to 69 years, 36.9% took at least 1 prescription pain medication in the past 30 days; of them, 18.8% used opioids, 9.7% nonsteroidal anti-inflammatory drugs, 8.5% muscle relaxants, and 6.9% gabapentin or pregabalin. Nonpain antidepressants and hypnotics were used by 17.8% and 4.7%, respectively. Opioids were used long-term in 76.9% of cases (median = 2 years) and were frequently coadministered with antidepressants, benzodiazepines, or hypnotics. Ninety-four percent of prescription opioids in the cLBP population were used by individuals with less than a college education. Opioids were the most widely used prescription analgesic class in community-based U.S. adults with cLBP and were often coadministered with other central nervous system-active medications. Opioid use was highly prevalent among less educated Americans with cLBP.

PERSPECTIVE

Because prescription opioid use is an issue of national concern, we examined pain-related prescription medication use in community-dwelling U.S. adults with cLBP. Opioids were the most common prescription pain medication, typically used long-term, in combination with other central nervous system-active agents, and disproportionately among individuals with less than a college education.

Drug dependence in patients with chronic pain: A retrospective study

Drug dependence, which can exist concurrently with chronic pain, is seen as one of the major causes of rapidly increasing medical expenses. However, drug dependence in patients with chronic pain has not been evaluated. The aim of this study was to identify the risk factors for drug dependence in patients with chronic noncancer pain.This retrospective study included 151 patients with chronic noncancer pain (43 males, 108 females; mean age, 72 years). Low back pain (LBP) occurred in 96 patients, whereas 22 had shoulder pain, 8 had hip pain, and 77 had knee pain. Patients were divided into drug dependence and nondrug dependence groups based on the Severity of Dependence Scale (SDS) scores. Patients with SDS scores ≥5 and <5 were classified into drug dependence and nondrug dependence groups, respectively. All patients completed self-report questionnaires. Factors that predict drug dependence were identified by performing univariate and multivariate analyses.Sixty (40%) of the 151 patients met the SDS criteria for drug dependence. Significant differences were found between patients with and without drug dependence for the LBP, hip pain, number of medications, and for the Numerical Rating Scale, Pain Disability Assessment Scale (PDAS), Hospital Anxiety and Depression Scale, and Pain Catastrophizing Scale (PCS) scores. Multiple regression analysis identified LBP, hip pain, PCS, and PDAS scores as factors related to drug dependence in patients with chronic noncancer pain.Drug dependence tends to differ in patients based on the location of their chronic pain. Pain catastrophizing and disability indicated a greater tendency for drug dependence. Thus, PCS and PDAS scores are useful screening tools for predicting drug dependence in patients with chronic pain.

An isobolographic analysis of the anti-nociceptive effect of geraniin in combination with morphine or diclofenac

BACKGROUND

Geraniin, a dehydroellagitannin, is a major component of the aqueous extract of the aerial parts of Phyllanthus muellerianus (Kuntze) Exell. (Euphorbiaceae). Several Phyllanthus species are traditionally used for painful disorders. The anti-nociceptive effects of the aqueous extract of the aerial parts of P. muellerianus and of geraniin have been scientifically established. The aim of the paper is to determine whether a combination of geraniin and diclofenac or geraniin and morphine leads to better anti-nociceptive effects.

METHODS

The nature of the interactions of morphine and diclofenac with geraniin was evaluated by undertaking the isobolographic analysis. Mice were treated with geraniin (3-30 mg/kg), morphine (1-10 mg/kg), and diclofenac (10-100 mg/kg) to obtain the ED50 values of the agents in the formalin test. Dose-response curves were then obtained and analyzed after the co-administration of geraniin with morphine or diclofenac in fixed ratio (1:1) combinations based on specific fractions (1/2, 1/4, and 1/8) of their respective ED50 values for the formalin test.

RESULTS

Geraniin was less potent than morphine but more potent than diclofenac in the formalin-induced nociception. The isobolographic analysis of geraniin/morphine (G/M) and geraniin/diclofenac combinations (G/D) at different fractions revealed the potentiation of their anti-nociceptive effects. The degrees of potentiation, which were calculated as interaction indices, showed synergism for both combinations in both phase I (G/M: 0.040, G/D: 0.017) and phase II (G/M: 0.004, G/D: 0.002) of the formalin test.

CONCLUSIONS

The present study demonstrates synergism for the co-administration of geraniin with both morphine and diclofenac.

Placebo and Active Treatment Additivity in Placebo Analgesia: Research to Date and Future Directions

Placebo analgesia is a robust experimental and clinical phenomenon. While our understanding of the mechanisms of placebo analgesia has developed rapidly, some central questions remain unanswered. Among the important questions is how placebo analgesia interacts with active analgesic effects. It is an assumption underlying double-blind randomized placebo-controlled trials (RCTs) that the true effect of a treatment can be determined by examining the effect of the active treatment arm and subtracting the response in the placebo group ("the assumption of additivity"). However, despite the importance of this assumption for the interpretation of RCTs, it has rarely been formally examined. This article reviews the assumption of additivity in placebo analgesia by examining studies employing factorial designs manipulating both the receipt of an active analgesic and instructions about the treatment being delivered. In reviewing the literature, we identified seven studies that allowed a test of additivity. Of these, four found evidence against additivity, while the remaining three studies found results consistent with additivity. While the limited available data are somewhat mixed, the evidence suggests that at least under some conditions the assumption of additivity does not hold in placebo analgesia. The concordance between mechanisms of the active analgesic and placebo analgesia may influence whether additivity occurs or not. However, more research using factorial designs is needed to disentangle the relationship between placebo analgesia and the active effect of analgesic treatments.

Improved Outcomes Associated With the Use of Intravenous Acetaminophen for Management of Acute Post-Surgical Pain in Cesarean Sections and Hysterectomies

Background

Post-surgical pain impacts many patient outcomes. Effective pain management increasingly relies on multimodal analgesia regimens in which acetaminophen (APAP) is a key component. The aim of our study was to examine the impact of oral APAP versus intravenous (IV) APAP as a component of post-surgical pain management after Cesarean sections and hysterectomies.

Methods

A retrospective analysis of the Cerner HealthFacts® database (from January, 2011 to December, 2015) was conducted to compare outcomes of Cesarean section and hysterectomy surgery patients who received oral APAP to those who received IV APAP post-surgically. Length of stay (LOS), daily morphine milligram equivalent (MME) consumption, the presence of potential opioid-related adverse events (ORADEs), and total pharmacy costs were assessed. Adjusted results were derived using inverse probability weighted regression adjustment (IPW-RA) estimators based on covariates that included demographics, comorbidities, patient clinical characteristics, and hospital characteristics.

Results

The study identified 29,124 Cesarean section patients (24,612 oral APAP; 4,512 IV APAP) and 9,767 hysterectomy surgery patients (5,586 oral APAP; 4,181 IV APAP). Compared to the oral APAP group, the IV APAP group had reductions in adjusted LOS (Cesarean section: -11.7% days (P < 0.001), hysterectomy: -11.8% days (P = 0.005)), lowered adjusted daily MME consumption from day 0 to day 3 (Cesarean section: -1.6 mg (P < 0.001), hysterectomy: -1.7 mg (P = 0.014)), and reduced risk of ORADEs for Cesarean sections (relative risk of 0.45, P < 0.001). Total pharmacy costs were not significantly different between the two APAP groups.

Conclusions

Post-surgical pain managed with IV APAP in patients undergoing Cesarean section or hysterectomy was associated with shorter LOS, reduced risk of ORADEs, and lower opioid consumption compared to patients managed with oral APAP, without adversely impacting total pharmacy costs.

Fifteen-minute consultation: Pain relief for children made simple-a pragmatic approach to prescribing oral analgesia in the postcodeine era

What are the most effective doses of simple oral analgesics such as paracetamol and ibuprofen for pain relief in children? Why can't I prescribe codeine phosphate for children anymore? Is oral morphine really a safe alternative to codeine phosphate, and if so what dose should I prescribe? These questions are frequently asked by clinicians who wish to give analgesics to children for pain relief. In this article I will address these questions and describe a pragmatic approach for pain relief using oral analgesics based on the best evidence available and my experience as a consultant paediatric anaesthetist.