Treatment with subcutaneous and transdermal fentanyl: results from a population pharmacokinetic study in cancer patients

Optimizing the Dosing Regimen During Rotation From Subcutaneous to Transdermal Administration of Fentanyl

CONTEXT

Subcutaneous (SC) administration of fentanyl allows for rapid dose titration to treat urgent cancer-related pain. After establishing the optimal fentanyl dose, patients typically rotate towards transdermal (TD) fentanyl patches. Continuing the SC fentanyl up to 12h after application of the patch led to elevated fentanyl concentrations and fentanyl-related toxicities. Based on these findings, and simulations using a pharmacokinetic (PK) model, SC fentanyl administration was discontinued immediately following the application of the patch.

OBJECTIVES

To validate the fentanyl rotation schedule by assessing the PK equivalence in fentanyl exposure before and after rotation.

METHODS

PK samples and clinical data were prospectively collected from 12 hours prior to rotation until 12 hours after rotation in patients with cancer-related pain undergoing fentanyl rotation.

RESULTS

Between December 2021 and September 2023, 29 evaluable patients were enrolled in the study. The 90% confidence interval (CI) of the geometric mean ratio between the post- over pre-rotation area under the curve (AUC) fell within the prespecified 0.8-1.25 equivalence interval (90% CI 1.05-1.16). Patient-reported intensity of both nausea (P = 0.047) and transpiration (P = 0.034) decreased post-rotation. Pain intensity and other adverse events did not differ significantly pre and post-rotation. One patient needed adjustment of opioid therapy 40 hours after rotation due to fentanyl-related toxicities.

CONCLUSION

The updated rotation scheme, implying a 1:1 dose conversion and discontinuation of SC fentanyl directly after rotation, resulted in equivalent fentanyl exposure pre and post-rotation. Moreover, the dosing regimen showed to be safe and efficacious during rotation. The new dosing regimen when rotating from SC to TD fentanyl can be effectively and safely implemented in routine palliative care.

Anti-Nociceptive Effect of Sufentanil Polymeric Dissolving Microneedle on Male Mice by Hot Plate Technique

Background

Despite the widespread use of opioids to manage severe pain, its systemic administration results in side effects. Among the subcutaneous and transdermal drug delivery systems developed to deal with adverse effects, microneedles have drawn attention due to their rapid action, high drug bioavailability, and improved permeability. Sufentanil (SUF) is an effective injectable opioid for treating severe pain. In this study, we investigated the analgesic effects of SUF using dissolvable microneedles.

Methods

SUF polymeric dissolvable microneedles were constructed through the mold casting method and characterized by SEM and FTIR analysis. Its mechanical strength was also investigated using a texture analyzer. Fluorescence microscopy was applied in vitro to measure the penetration depth of microneedle arrays. Irritation and microchannel closure time, drug release profile, and hemocompatibility test were conducted for the validation of microneedle efficiency. Hot plate test was also used to investigate the analgesic effect of microneedle in an animal model.

Results

Local administration of SUF via dissolving microneedles had an effective analgesic impact. One hour after administration, there was no significant difference between the subcutaneous and the microneedle groups, and the mechanical properties were within acceptable limits.

Conclusion

Microneedling is an effective strategy in immediate pain relief compared to the traditional methods.

Advancements in transdermal drug delivery: A comprehensive review of physical penetration enhancement techniques

Transdermal drug administration has grown in popularity in the pharmaceutical research community due to its potential to improve drug bioavailability, compliance among patients, and therapeutic effectiveness. To overcome the substantial barrier posed by the stratum corneum (SC) and promote drug absorption within the skin, various physical penetration augmentation approaches have been devised. This review article delves into popular physical penetration augmentation techniques, which include sonophoresis, iontophoresis, magnetophoresis, thermophoresis, needle-free injection, and microneedles (MNs) Sonophoresis is a technique that uses low-frequency ultrasonic waves to break the skin's barrier characteristics, therefore improving drug transport and distribution. In contrast, iontophoresis uses an applied electric current to push charged molecules of drugs inside the skin, effectively enhancing medication absorption. Magnetophoresis uses magnetic fields to drive drug carriers into the dermis, a technology that has shown promise in aiding targeted medication delivery. Thermophoresis is the regulated heating of the skin in order to improve drug absorption, particularly with thermally sensitive drug carriers. Needle-free injection technologies, such as jet injectors (JIs) and microprojection arrays, offer another option by producing temporary small pore sizes in the skin, facilitating painless and effective drug delivery. MNs are a painless, minimally invasive method, easy to self-administration, as well as high drug bioavailability. This study focuses on the underlying processes, current breakthroughs, and limitations connected with all of these approaches, with an emphasis on their applicability in diverse therapeutic areas. Finally, a thorough knowledge of these physical enhancement approaches and their incorporation into pharmaceutical research has the potential to revolutionize drug delivery, providing more efficient and secure treatment choices for a wide range of health-related diseases.

Variant-based heritability assessment of dexmedetomidine and fentanyl clearance in pediatric patients

Despite complex pathways of drug disposition, clinical pharmacogenetic predictors currently rely on only a few high effect variants. Quantification of the polygenic contribution to variability in drug disposition is necessary to prioritize target drugs for pharmacogenomic approaches and guide analytic methods. Dexmedetomidine and fentanyl, often used in postoperative care of pediatric patients, have high rates of inter-individual variability in dosing requirements. Analyzing previously generated population pharmacokinetic parameters, we used Bayesian hierarchical mixed modeling to measure narrow-sense (additive) heritability (h SNP 2 ) of dexmedetomidine and fentanyl clearance in children and identify relative contributions of small, moderate, and large effect-size variants toh SNP 2 . We used genome-wide association studies (GWAS) to identify variants contributing to variation in dexmedetomidine and fentanyl clearance, followed by functional analyses to identify associated pathways. For dexmedetomidine, median clearance was 33.0 L/h (interquartile range [IQR] 23.8-47.9 L/h) andh SNP 2 was estimated to be 0.35 (90% credible interval 0.00-0.90), with 45% ofh SNP 2 attributed to large-, 32% to moderate-, and 23% to small-effect variants. The fentanyl cohort had median clearance of 8.2 L/h (IQR 4.7-16.7 L/h), with estimatedh SNP 2 of 0.30 (90% credible interval 0.00-0.84). Large-effect variants accounted for 30% ofh SNP 2 , whereas moderate- and small-effect variants accounted for 37% and 33%, respectively. As expected, given small sample sizes, no individual variants or pathways were significantly associated with dexmedetomidine or fentanyl clearance by GWAS. We conclude that clearance of both drugs is highly polygenic, motivating the future use of polygenic risk scores to guide appropriate dosing of dexmedetomidine and fentanyl.

Personalized Medicine for Classical Anesthesia Drugs and Cancer Progression

In this review, we aim to discuss the use and effect of five different drugs used in the induction of anesthesia in cancer patients. Propofol, fentanyl, rocuronium, sugammadex, and dexamethasone are commonly used to induce anesthesia and prevent pain during surgery. Currently, the mechanisms of these drugs to induce the state of anesthesia are not yet fully understood, despite their use being considered safe. An association between anesthetic agents and cancer progression has been determined; therefore, it is essential to recognize the effects of all agents during cancer treatment and to evaluate whether the treatment provided to the patients could be more precise. We also highlight the use of in silico tools to review drug interaction effects and safety, as well as the efficacy of the treatment used according to different subgroups of patients.

Evaluation of in vitro/in vivo correlations for three fentanyl transdermal delivery systems using in vitro skin permeation testing and human pharmacokinetic studies under the influence of transient heat application

The value of developing an in vitro/in vivo correlation (IVIVC) is substantial in biopharmaceutical drug development because once the model is developed and validated, an in vitro method may be used to efficiently assess and predict drug product performance in vivo. In this study, three bioequivalent, matrix-type, fentanyl transdermal delivery systems (TDS) were evaluated in vitro using an in vitro permeation test (IVPT) and dermatomed human skin, and in vivo in human pharmacokinetic (PK) studies under harmonized study designs to evaluate IVIVC. The study designs included 1 h of transient heat application (42 ± 2 °C) at either 11 h or 18 h after TDS application to concurrently investigate the influence of heat on drug bioavailability from TDS and the feasibility of IVPT to predict the effects of heat on TDS in vivo. Level A (point-to-point) and Level C (single point) IVIVCs were evaluated by using PK-based mathematical equations and building IVIVC models between in vitro fraction of drug permeation and in vivo fraction of drug absorption. The study results showed that the three differently formulated fentanyl TDS have comparable (p > 0.05) heat effects both in vitro and in vivo. In addition, the predicted steady-state concentration (C_ss) from in vitro flux data and the observed C_ss in vivo showed no significant differences (p > 0.05). However, the effects of heat on enhancement of fentanyl bioavailability observed in vivo were found to be greater compared to those observed in vitro for all three drug products, resulting in a weak prediction of the impact of heat on bioavailability from the in vitro data. The results from the current work suggest that while IVPT can be a useful tool to evaluate the performance of fentanyl TDS in vivo with a relatively good predictability at a normal temperature condition and to compare the effect of heat on drug delivery from differently formulated TDS, additional testing measures would enhance the ability to predict the heat effects in vivo with a lower prediction error.

Drug Exposure to Establish Pharmacokinetic-Response Relationships in Oncology

In the oncology field, understanding the relationship between the dose administered and the exerted effect is particularly important because of the narrow therapeutic index associated with anti-cancer drugs and the high interpatient variability. Therefore, in this review, we provide a critical perspective of the different methods of characterising treatment exposure in the oncology setting. The increasing number of modelling applications in oncology reflects the applicability and the impact of pharmacometrics on all phases of the drug development process and patient management as well. Pharmacometric modelling is a worthy component within the current paradigm of model-based drug development, but pharmacometric modelling techniques are also accessible for the clinician in the optimisation of current oncology therapies. Consequently, the application of population models in a hospital setting by generating close collaborations between physicians and pharmacometricians is highly recommended, providing a systematic means of developing and assessing model-based metrics as 'drivers' for various responses to treatments, which can then be evaluated as predictors for treatment success. Characterising the key determinants of variability in exposure is of particular importance for anticancer agents, as efficacy and toxicity are associated with exposure. We present the different strategies to describe and predict drug exposure that can be applied depending on the data available, with the objective of obtaining the most useful information in the patients' favour throughout the full drug cycle. Therefore, the objective of the present article is to review the different approaches used to characterise a patient's exposure to oncology drugs, which will result in a better understanding of the time course of the response and the magnitude of interpatient variability.

Population pharmacokinetic model of subcutaneous fentanyl in older acute care patients

PURPOSE

Subcutaneous fentanyl injection is commonly prescribed to manage acute pain in older patients; however, there is a gap in the literature describing the pharmacokinetic parameters for this route of administration in this population. The aim of this study was to develop and evaluate a population pharmacokinetic model for subcutaneous fentanyl injection in older patients.

METHODS

Twenty-one patients who received subcutaneous fentanyl injections (50 to 75 μg) were recruited. Fentanyl concentrations were determined using a validated liquid chromatography/tandem mass spectrometry method. A population pharmacokinetic model was developed using non-linear mixed-effects modelling. A base model was selected based on the Akaike information criterion. Age, sex, body weight, number of previous fentanyl doses, number of prescribed medications, creatinine clearance, Charlson Comorbidity Index, Identification of Seniors at Risk score and concurrent use of CYP3A4 inhibitors were covariates considered for inclusion. A p value of < 0.05 was considered statistically significant for inclusion of covariates in the final model by stepwise addition. The simulation performance of the model was assessed by visual predictive check.

RESULTS

A one-compartment, first-order absorption with lag time and linear elimination model was the best to fit to the fentanyl concentration data. The absorption rate constant was 0.136 h^-1 (between subject variability (BSV), 46%), lag time 0.66 h (BSV 51%), apparent volume of distribution 6.28 L (BSV 30%), and apparent clearance 16.3 L.h^-1 (BSV 54%). The Charlson Comorbidity Index was the only covariate included in the final model, where a higher value of the index increased fentanyl exposure and C_max.

CONCLUSION

This is the first report of subcutaneous fentanyl population pharmacokinetic model to evaluate fentanyl pharmacokinetic in older patients. The between subject variability in clearance and subcutaneous absorption rate was relatively high, and some patients recorded high fentanyl concentrations in the context of their titration to effect.

Preparation and evaluation of functional allopurinol imprinted starch based biomaterials for transdermal drug delivery

This study focuses on the synthesis of functional allopurinol (ALP) imprinted biomaterials for a transdermal drug delivery using mung bean starch (MBS), polyvinyl alcohol (PVA), sodium benzoate (SB) as a crosslinking agent, and poloxamer (PX) as a thermo-sensitive polymer. Prepared functional biomaterials were characterized and evaluated by SEM, FT-IR analysis, and physical properties. Results of ALP recognition properties indicated that adsorbed amounts (Q) of ALP on functional ALP imprinted biomaterials were 3.8 to 4.9-fold higher than that of non-ALP imprinted biomaterial. Results of ALP release revealed that the ALP release rate for PX added biomaterials was 1.10 (36.5 °C) or 1.30 (45 °C) times faster than that at 25 °C. These results indicate that functional ALP imprinted biomaterials have thermo-sensitive properties due to the addition of PX. Results of ALP release using artificial skin indicated that ALP release was increased at a relatively steady-state rate for 3 h and that the ALP release behavior followed the non-Fickian diffusion mechanism.

[Adverse drug reactions profiles for abiraterone and enzalutamide: A pharmacovigilance descriptive analysis]

OBJECTIVE

The aim of this study was to describe the profile of adverse drug reactions (ADRs) observed with abiraterone and enzalutamide, based on cases registered in the French regional pharmacovigilance centres to identify potential pharmacovigilance signals.

METHODS

We extracted from the French pharmacovigilance database all cases of ADRs or drug interactions involving abiraterone or enzalutamide from the time they market authorization date until December 31st, 2017. Signal detection results have been transmitted by the French Agency for Health Products (ANSM). The data were compared with those of the risk management plans for each drug and the literature.

RESULTS

Among the 233 observations analyzed, nearly 62% involved abiraterone as a suspect drug and 38% involved enzalutamide; only 1 case involved both drugs. The ADRs profile is different between the drugs. Abiraterone is mostly associated with expected cardiac diseases (heart failure, and QT prolongation), expected with the drug. Also described, several cases of hepatotoxicity have been reported, however some cases with fatal outcome suggest that despite a follow-up of the liver function tests, it is difficult to anticipate this risk. Signals concerning acute renal failure and ischemic stroke have arisen. Enzalutamide is more particularly associated with various neurological disorders (convulsions, hallucinations, fatigue, and memory impairment) expected with the drug. While ischemic heart disease is also expected, signals of heart failure and atrial fibrillation have arisen. A potential hepatotoxicity of the molecule is discussed because of cases of cholestatic hepatitis.

CONCLUSION

The analysis of the French pharmacovigilance database cases allows to confirm an expected and monitored risk profile in the risk management plan for both drugs. Several signals have arisen, some of which will be investigated through a pharmacoepidemiology study.

Subcutaneous fentanyl for labour analgesia: a retrospective case note review

BACKGROUND

In 2017, a South Australia Perinatal Practice Guideline was introduced state-wide for the use of subcutaneous fentanyl for labour analgesia as a replacement for intramuscular pethidine. We retrospectively reviewed the implementation of this practice change in our institution.

METHODS

A retrospective review of maternal and neonatal case notes for the first 100 women administered subcutaneous fentanyl in labour at a single tertiary referral centre for maternity care, between February and June 2017.

RESULTS

Of the 102 women administered subcutaneous fentanyl, the majority (55%) were primipara, with an average maternal age of 29 years and body mass index of 27 kg/m². The median total fentanyl dose administered was 200 µg and the average time from last dose to birth was 3 h. The majority of women (70%) did not require additional rescue labour analgesia and 80% had a spontaneous vaginal birth. All neonates had a 5-min Apgar score >7. The median Apgar score at 1 and 5 min was 9. No neonate had an arterial cord blood pH <7.1. The mean arterial and venous cord blood pH was 7.3. The average time for neonates to establish breathing was 1 min and the median postnatal length of stay was two days.

CONCLUSIONS

Subcutaneous fentanyl for labour analgesia appears effective and has a low incidence of adverse events.

Indian Society for Study of Pain, Cancer Pain Special Interest Group Guidelines on Pharmacological Management of Cancer Pain (Part I)

The Indian Society for Study of Pain (ISSP), Cancer Pain Special Interest Group guidelines on pharmacological management of cancer pain in adults provides a structured, step-wise approach which will help to improve the management of cancer pain and to provide the patients with a minimally acceptable quality of life. The guidelines have been developed based on the available literature and evidence, to suit the needs, patient population, and situations in India. A questionnaire based on the key elements of each sub drafts addressing certain inconclusive areas where evidence was lacking, was made available on the ISSP website, and circulated by E-mail to all the ISSP and Indian Association of Palliative Care (IAPC) members. We recommend that analgesics for cancer pain management should follow the World Health Organization three-step analgesic ladder appropriate for the severity of pain. The use of paracetamol and nonsteroidal anti-inflammatory drugs alone or in combination with opioids for mild-to-moderate pain should be used. For mild-to-moderate pain, weak opioids such as tramadol, tapentadol, and codeine can be given in combination with nonopioid analgesics. We recommend morphine as the opioid of first choice for moderate-to-severe cancer pain.

Converting from Transdermal to Buccal Formulations of Buprenorphine: A Pharmacokinetic Meta-Model Simulation in Healthy Volunteers

Objective

To develop a model to predict buprenorphine plasma concentrations during transition from transdermal to buccal administration.

Design

Population pharmacokinetic model-based meta-analysis of published data.

Methods

A model-based meta-analysis of available buprenorphine pharmacokinetic data in healthy adults, extracted as aggregate (mean) data from published literature, was performed to explore potential conversion from transdermal to buccal buprenorphine. The time course of mean buprenorphine plasma concentrations following application of transdermal patch or buccal film was digitized from available literature, and a meta-model was developed using specific pharmacokinetic parameters (e.g., absorption rate, apparent clearance, and volumes of distribution) derived from analysis of pharmacokinetic data for intravenously, transdermally, and buccally administered buprenorphine.

Results

Data from six studies were included in this analysis. The final transdermal absorption model employed a zero-order input rate that was scaled to reflect a nominal patch delivery rate and time after patch application (with decline in rate over time). The transdermal absorption rate constant became zero following patch removal. Buccal absorption was a first-order process with a time lag and bioavailability term. Simulations of conversion from transdermal 20 mcg/h and 10 mcg/h to buccal administration suggest that transition can be made rapidly (beginning 12 hours after patch removal) using the recommended buccal formulation titration increments (75-150 mcg) and schedule (every four days) described in the product labeling.

Conclusions

Computer modeling and simulations using a meta-model built from data extracted from publications suggest that rapid and straightforward conversion from transdermal to buccal buprenorphine is feasible.

Influence of aprepitant and localization of the patch on fentanyl exposure in patients with cancer using transdermal fentanyl

Background and Objectives

The cutaneous fentanyl patch is widely used to treat continuous pain in patients with cancer. Its use is hampered by a high inter- and intrapatient pharmacokinetic variability. Factors that influence this pharmacokinetic variability are largely unclear. The aim of these studies was to test if common patient variables, i) the use of the moderate CYP3A4 inhibitor aprepitant and ii) the localization of the fentanyl patch (upper arm versus thorax) influence systemic exposure to fentanyl in patients with cancer using a transdermal fentanyl patch.

Results

The AUC_{0-6 h} of fentanyl was 7.1% (95% CI: -28% to +19%) lower if patients concurrently used aprepitant, compared to the period when patients used fentanyl only. The AUC_{0-4 h} of fentanyl was 7.4% (95% CI: -22% to +49%) higher when the cutaneous fentanyl patch was applied to the upper arm compared to application at the thorax.

Conclusions

Neither the concurrent use of aprepitant, nor the localization of the fentanyl patch showed a statistically significant influence on fentanyl pharmacokinetics.

Methods

We performed two prospective cross-over pharmacokinetic intervention studies. Both studies had two eight-day study periods. At day 8 of each study period blood samples were collected for pharmacokinetic analysis. In each study 14 evaluable patients were included.

Device-assisted transdermal drug delivery

Transdermal drug delivery is a prospective drug delivery strategy to complement the limitations of conventional drug delivery systems including oral and injectable methods. This delivery route allows both convenient and painless drug delivery and a sustained release profile with reduced side effects. However, physiological barriers in the skin undermine the delivery efficiency of conventional patches, limiting drug candidates to small-molecules and lipophilic drugs. Recently, transdermal drug delivery technology has advanced from unsophisticated methods simply relying on natural diffusion to drug releasing systems that dynamically respond to external stimuli. Furthermore, physical barriers in the skin have been overcome using microneedles, and controlled delivery by wearable biosensors has been enabled ultimately. In this review, we classify the evolution of advanced drug delivery strategies based on generations and provide a comprehensive overview. Finally, the recent progress in advanced diagnosis and therapy through customized drug delivery systems based on real-time analysis of physiological cues is highlighted.

Bioanalytical methods for the quantification of hydromorphone, fentanyl, norfentanyl, morphine, morphine-3ß-glucuronide and morphine-6ß-glucuronide in human plasma

The aim of this study was to develop an assay for the quantification of hydromorphone, morphine, fentanyl and the metabolites norfentanyl, morphine-3ß-glucuronide and morphine-6ß-glucuronide in human plasma to support pharmacokinetic studies investigating the large interpatient variability in response to opioid treatment. For the quantitation of hydromorphone, morphine, fentanyl and its metabolite norfentanyl aliquots of 200μL human potassium EDTA plasma were deproteinized with deuterated internal standards in a mixture of acetonitrile and acetone, followed by a liquid-liquid extraction with 4% ammonium hydroxide and ethyl acetate. Morphine-3ß-glucuronide and morphine-6ß-glucuronide were extracted by a solid phase extraction using 10mM ammonium carbonate pH 8.8 and a deuterated internal standards solution. Morphine, hydromorphone, fentanyl and norfentanyl were separated on an Aquity UPLC^® BEH C18 column 1.7μm, 100mm×2.1mm at 50°C. Separation, was achieved on a gradient of methanol with an overall run time of 6min. The compounds were quantified by triple-quadrupole mass spectrometry in the positive ion electrospray ionization mode. Morphine-3ß-glucuronide and morphine-6ß-glucuronide were separated on a VisionHT C18-P; 3μm 2.1×50mm, column at 40°C on a gradient of acetonitrile, with an overall run time of 10min. Both methods were precise and accurate, with within-run and between-run precisions within acceptable limits and accuracy ranging from 84.0 to 105.5%. The methods were successfully applied to support clinical pharmacological studies in patients treated with opioids for the treatment of moderate to severe cancer-related pain.

A review of factors explaining variability in fentanyl pharmacokinetics; focus on implications for cancer patients

Fentanyl is a strong opioid that is available for various administration routes, and which is widely used to treat cancer-related pain. Many factors influence the fentanyl pharmacokinetics leading to a wide inter- and intrapatient variability. This systematic review summarizes multiple studied factors that potentially influence fentanyl pharmacokinetics with a focus on implications for cancer patients. The use of CYP3A4 inhibitors and inducers, impaired liver function, and heating of the patch potentially influence fentanyl pharmacokinetics in a clinically relevant way. In elderly patients, current data suggest that we should carefully dose fentanyl due to alterations in absorption and metabolism. The influence of BMI and gender on fentanyl pharmacokinetics is questionable, most probably due to a large heterogeneity in the published studies. Pharmacogenetics, e.g. the CYP3A5*3 gene polymorphism, may influence fentanyl pharmacokinetics as well, although further study is warranted. Several other factors have been studied but did not show significant and clinically relevant effects on fentanyl pharmacokinetics. Unfortunately, most of the published papers that studied factors influencing fentanyl pharmacokinetics describe healthy volunteers instead of cancer patients. Results from the studies in volunteers may not be simply extrapolated to cancer patients because of multiple confounding factors. To handle fentanyl treatment in a population of cancer patients, it is essential that physicians recognize factors that influence fentanyl pharmacokinetics, thereby preventing potential side-effects and increasing its efficacy.