Minor contribution of cytochrome P450 3A activity on fentanyl exposure in palliative care cancer patients

Guidelines for Rational Clinical Use of Fentanyl Transdermal Patch

Pain is one of the most common clinical symptoms of cancer patients, seriously affecting the quality of life of patients and bringing heavy mental and economic burden to families and society. The treatment of cancer pain in China is facing numerous challenges, one of which includes the irrational usage of analgesic drugs in clinical practice. As a strong opioid analgesic, transdermal fentanyl patch has been widely used due to its convenient clinical application and obvious therapeutic effect. Several basic-level hospitals and even general hospitals in China fail to appropriate the application of drugs in clinical application due to the lack of understanding of the pharmacological characteristics and clinical application of fentanyl transdermal patch by medical staff, seriously affecting the treatment quality. Therefore, it is imperative to strengthen the rational use and management of fentanyl transdermal patches. Accordingly, the initiation by the Cancer Rehabilitation and Palliative Treatment Professional Committee of the Hubei Anti-cancer Association launched the compilation of the "Guidelines for Rational Clinical Use of Fentanyl Transdermal Patch" (from now on referred to as the "Guidelines") in Hubei Province, China. The experts in the preparation group are experts in many disciplines, such as medicine, pharmacy, and nursing. The expert group determines the outline, prepares the required regulations, and revises it repeatedly. Moreover, these experts put forward suggestions for revision to strictly control the accuracy and scientific authenticity of the contents of the "Guide". Finally, all experts of the preparation team certify and finalize the draft. This "Guide" prepared by experts of the Cancer Rehabilitation and Palliative Treatment Professional Committee of the Hubei Anti-cancer Association and the expert advisory group with joint efforts, aims to play a positive role in promoting the rational clinical use of fentanyl transdermal patch, reducing the mental and economic burden of patients, and ensuring medical quality and medical safety.

Assessment of Drug-Drug Interaction Risk Between Intravenous Fentanyl and the Glecaprevir/Pibrentasvir Combination Regimen in Hepatitis C Patients Using Physiologically Based Pharmacokinetic Modeling and Simulations

INTRODUCTION

An unsafe injection practice is one of the major contributors to new hepatitis C virus (HCV) infections; thus, people who inject drugs are a key population to prioritize to achieve HCV elimination. The introduction of highly effective and well-tolerated pangenotypic direct-acting antivirals, including glecaprevir/pibrentasvir (GLE/PIB), has revolutionized the HCV treatment landscape. Glecaprevir is a weak cytochrome P450 3A4 (CYP3A4) inhibitor, so there is the potential for drug-drug interactions (DDIs) with some opioids metabolized by CYP3A4, such as fentanyl. This study estimated the impact of GLE/PIB on the pharmacokinetics of intravenous fentanyl by building a physiologically based pharmacokinetic (PBPK) model.

METHODS

A PBPK model was developed for intravenous fentanyl by incorporating published information on fentanyl metabolism, distribution, and elimination in healthy individuals. Three clinical DDI studies were used to verify DDIs within the fentanyl PBPK model. This model was integrated with a previously developed GLE/PIB PBPK model. After model validation, DDI simulations were conducted by coadministering GLE 300 mg + PIB 120 mg with a single dose of intravenous fentanyl (0.5 µg/kg).

RESULTS

The predicted maximum plasma concentration ratio between GLE/PIB + fentanyl and fentanyl alone was 1.00, and the predicted area under the curve ratio was 1.04, suggesting an increase of only 4% in fentanyl exposure.

CONCLUSION

The administration of a therapeutic dose of GLE/PIB has very little effect on the pharmacokinetics of intravenous fentanyl. This negligible increase would not be expected to increase the risk of fentanyl overdose beyond the inherent risks related to the amount and purity of the fentanyl received during recreational use.

An individualized digital twin of a patient for transdermal fentanyl therapy for chronic pain management

Fentanyl transdermal therapy is a suitable treatment for moderate-to-severe cancer-related pain. The inter-individual variability of the patients leads to different therapy responses. This study aims to determine the effect of physiological features on the achieved pain relief. Therefore, a set of virtual patients was developed by using Markov chain Monte Carlo (MCMC) based on actual patient data. The members of this virtual population differ by age, weight, gender, and height. Tailored digital twins were developed using these correlated, individualized parameters to propose a personalized therapy for each patient. It was shown that patients of different ages, weights, and gender have significantly different fentanyl blood uptake, plasma fentanyl concentration, pain relief, and ventilation rate. In the digital twins, we included the virtual patients' response to the treatment, namely, pain relief. Therefore, the digital twin was able to adjust the therapy in silico to have more efficient pain relief. By implementing digital-twin-assisted therapy, the average pain intensity decreased by 16% compared to conventional therapy. The median time without pain increased by 23 h over 72 h. Therefore, the digital twin can be successfully used in individual control of transdermal therapy to reach higher pain relief and maintain steady pain relief. (Created with BioRender.com).

Predicting transdermal fentanyl delivery using physics-based simulations for tailored therapy based on the age

Transdermal fentanyl patches are an effective alternative to the sustained release of oral morphine for chronic pain management. Due to the narrow therapeutic range of fentanyl, the concentration of fentanyl in the blood needs to be carefully monitored. Only then can effective pain relief be achieved while avoiding adverse effects such as respiratory depression. This study developed a physics-based digital twin of a patient by implementing drug uptake, pharmacokinetics, and pharmacodynamics models. The twin was employed to predict the in-silico effect of conventional fentanyl transdermal in a 20–80-year-old virtual patient. The results show that, with increasing age, the maximum transdermal fentanyl flux and maximum concentration of fentanyl in the blood decreased by 11.4% and 7.0%, respectively. However, the results also show that as the patient's age increases, the pain relief increases by 45.2%. Furthermore, the digital twin was used to propose a tailored therapy based on the patient's age. This predesigned therapy customized the duration of applying the commercialized fentanyl patches. According to this therapy, a 20-year-old patient needs to change the patch 2.1 times more frequently than conventional therapy, which leads to 30% more pain relief and 315% more time without pain. In addition, the digital twin was updated by the patient's pain intensity feedback. Such therapy increased the patient's breathing rate while providing effective pain relief, so a safer treatment. We quantified the added value of a patient's physics-based digital twin and sketched the future roadmap for implementing such twin-assisted treatment into the clinics.

Evaluation of CYP2C19 activity using microdosed oral omeprazole in humans

Purpose

To investigate the suitability of microdosed oral omeprazole for predicting CYP2C19 activity in vivo in combination with simultaneous assessment of CYP3A and CYP2D6 activity using both microdosed midazolam and yohimbine.

Methods

An open, fixed-sequence study was carried out in 20 healthy participants. Single microdosed (100 µg) and therapeutic (20 mg) doses of omeprazole were evaluated without comedication and after administration of established CYP2C19 perpetrators fluconazole (inhibition) and rifampicin (induction). To prevent degradation of the uncoated omeprazole microdose, sodium bicarbonate buffer was administered. The pharmacokinetics of omeprazole and its 5-hydroxy-metabolite were assessed as well as the pharmacokinetics of midazolam and yohimbine to estimate CYP3A4 and CYP2D6 activity.

Results

Calculated pharmacokinetic parameters after administration of 100 µg and 20 mg omeprazole in healthy subjects suggest dose proportionality. Omeprazole clearance was significantly decreased by fluconazole from 388 [95% CI: 266–565] to 47.2 [42.8–52.0] mL/min after 20 mg omeprazole and even further after 100 µg omeprazole (29.4 [24.5–35.1] mL/min). Rifampicin increased CYP2C19-mediated omeprazole metabolism. The omeprazole hydroxylation index was significantly related to omeprazole clearance for both doses. Both fluconazole and rifampicin altered CYP3A4 activity whereas no change of CYP2D6 activity was observed at all.

Conclusions

Microdosed oral omeprazole is suitable to determine CYP2C19 activity, also during enzyme inhibition and induction. However, the administration of sodium bicarbonate buffer also had a small influence on all victim drugs used.

Trial registration

EudraCT: 2017–004270-34.

Supplementary information

The online version contains supplementary material available at 10.1007/s00228-022-03304-3.