Single-dose and steady-state pharmacokinetics of fentanyl buccal tablet in healthy volunteers

Severe and Fatal Fentanyl Poisonings from Transdermal Systems after On-Skin and Ingestion Application

In recent years, the administration of fentanyl (FNTL) implicitly in transdermal drug delivery systems (TDDS) has vastly increased in chronic pain treatment. Non-medical and uncontrolled use of FNTL in TFDS (transdermal fentanyl delivery systems) may reveal toxic effects by the route of exposure, dermal or alternative, by ingestion of patches, and drug release in the stomach. The purpose of this study was to present three different cases of FNTL poisonings, two of which resulted in death due to TFDS abuse. The first case is a 66-year-old woman treated for accidental FTNL poisoning resulting in acute respiratory distress syndrome. Two remaining cases are a 31-year-old woman and a 25-year-old man who died as a result of FNTL overdose after on-skin and ingestion application of the drug patches. During the hospitalization of the 66-year-old patient, in blood samples, FNTL was confirmed at a concentration of 10.0 ng/mL. Tests run on blood taken from the corpses of 25- and 31-year-old patients exhibited FNTL presence in concentrations of 29.1 ng/mL and 38.7 ng/mL, respectively. The various routes of administration and ultimately toxic effects are important to present because, in TDDS, fentanyl can be a reason for severe to fatal poisoning, as shown by the three cases above.

Health effects from unintentional occupational exposure to opioids among law enforcement officers: Two case investigations

Recent increases in the rate of drug overdose-related deaths, the emergence of potent opioids such as carfentanil, and media reports of incidents have raised concerns about the potential for work-related exposure to a variety of illicit drugs among law enforcement officers (LEOs), other emergency responders, and other workers in the United States. To characterize the risk associated with unintentional occupational exposure to drugs, we retrospectively investigated two incidents that occurred in 2017 and 2018 where LEOs were exposed to opioid and stimulant drugs and experienced health effects. We interviewed five affected LEOs and others. We reviewed records, including emergency department documentation, incident reports, forensic laboratory results, and when available, body camera footage. Multiple drug types, including opioids and nonopioids, were present at each incident. Potential routes of exposure varied among LEOs and were difficult to characterize with certainty. Health effects were not consistent with severe, life-threatening opioid toxicity, but temporarily precluded affected LEOs from performing their essential job duties. While health risks from occupational exposure to drugs during law enforcement activities cannot currently be fully characterized with certainty, steps to prevent such exposures should be implemented now. The creation and implementation of appropriate controls plus education and training are both important to protecting first responders from these hazardous agents. To more fully characterize potential exposures, timely prospective toxicological evaluation of affected responders is recommended.

Rapid acting fentanyl formulations in breakthrough pain in cancer. Drug selection by means of the System of Objectified Judgement Analysis

Drug selection of rapid acting fentanyl formulations in the treatment of breakthrough pain in patients with cancer is performed by the System of Objectified Judgement Analysis method. All seven available formulations were included in the analysis. The following selection criteria were used: number of available strengths, variability in the rate of absorption, interactions, clinical efficacy, side effects, ease of administration and documentation. No direct double-blind comparative studies between two or more formulations were identified and the clinical documentation of all formulations is limited. The most distinguishing criterion was ease of use. This led to slightly higher scores for Abstral, Instanyl and PecFent than for the other formulations. The pros and cons of each formulation should be discussed with the patient, and the most suitable formulation selected for each individual patient.

Transmucosal Immediate-Release Fentanyl for Breakthrough Cancer Pain: Opportunities and Challenges for Use in Palliative Care

Opioids are used to treat breakthrough cancer pain (BTCP) and can be classified by relative duration and onset of action. Regulatory approvals of numerous transmucosal immediate-release fentanyl (TIRF) formulations provide alternative options to palliative care-trained providers in the management of BTCP. TIRFs have been formulated as a sublingual tablet, sublingual spray, intranasal spray, pectin-based nasal spray, buccal tablet, and buccal soluble film. Differences exist between TIRFs regarding formulation design and dosing to treat BTCP. Opportunities for use include palliation of BTCP in head and neck cancer and/or radiation-induced mucositis. The purpose of this review is to discuss TIRF formulation and dosing, pharmacokinetics, clinical efficacy, patient acceptability, and safety/tolerability. In addition, barriers to TIRF utilization will be discussed.

Clinical pharmacology of fentanyl buccal tablet for the treatment of breakthrough pain

Fentanyl buccal tablet (FBT) is a new formulation of fentanyl providing rapid-onset analgesia for the treatment of breakthrough pain. FBT has been approved for the management of breakthrough pain in patients with cancer who are already receiving and who are tolerant to opioid therapy for underlying persistent pain. FBT has demonstrated a favorable pharmacokinetic profile, which is closely aligned to the rapid onset and duration of an episode of breakthrough pain, and is generally safe and well tolerated.

A review of the pharmacokinetic profile of transmucosal fentanyl formulations

BACKGROUND AND OBJECTIVES

Breakthrough pain (BTP) is a transitory flare of moderate-to-severe pain that occurs in patients with stable, controlled persistent pain. Management of BTP episodes is difficult because frequency, time-to-peak intensity, and duration of episodes vary both within and between individuals. Formulations of fentanyl that use a buccal, sublingual, or nasal transmucosal route of administration have been developed for the treatment of BTP in opioid-tolerant patients with cancer. These formulations allow rapid passage into the bloodstream and avoid first-pass metabolism and, therefore, are more likely to match the time-course of BTP episodes than are oral formulations. The purposes of this analysis were to identify and review published data describing the pharmacokinetic properties of rapid-onset fentanyl formulations and to evaluate these properties in view of the temporal dynamic characteristics of BTP in order to help guide medical practice.

METHODS

Relevant publications were searched in the PubMed database from 1998. The plasma drug concentration-time profile of each formulation obtained from the identified studies was adjusted to a consistent scale for comparison.

RESULTS

The data revealed that the various transmucosal formulations resulted in three typical plasma fentanyl concentration profiles: (1) type 1: a very rapid rise and short duration; (2) type 2: a rapid increase and sustained intensity; and (3) type 3: a slower onset and longer duration.

CONCLUSIONS

Given the substantial variability of BTP episodes experienced by patients, these pharmacokinetic differences may provide useful information for a physician who is selecting a rapid-onset opioid medication for a patient.

Fentanyl (transmucosal)

Therapeutic Reviews aim to provide essential independent information for health professionals about drugs used in palliative and hospice care. Additional content is available on www.palliativedrugs.com. Country-specific books (Hospice and Palliative Care Formulary USA, and Palliative Care Formulary, British and Canadian editions) are also available and can be ordered from www.palliativedrugs.com. The series editors welcome feedback on the articles (hq@palliativedrugs.com).

A review of transbuccal fentanyl use in the emergency department

Patients with severe, painful injuries and illnesses treated in the emergency department are commonly administered opioid medications. Intravenous administration provides the most rapid onset of pain relief and is readily titrated. Fentanyl, administered intravenously, is well documented as an effective medication for pain management in the emergency department. It is preferred in many settings due to its minimal hemodynamic effects, as compared to other commonly used opioids. However, not all patients require intravenous access. These patients are given orally administered pain medications. The oral route is effective at minimizing pain but has a much slower onset of action when compared to the intravenous route. As an alternative to the slower onset of action seen with oral opioids, this paper discusses the use of fentanyl buccal tablet for pain management in the emergency department. Fentanyl buccal tablets are readily absorbed, with a bioavailability of approximately 65%, and have a more rapid onset of action than achieved with traditional oral opioids used in the emergency department.

Fentanyl for breakthrough pain: a systematic review

The purpose of this article is to systematically review the use of fentanyl as an analgesic for breakthrough pain. This article found that the oral transmucosal fentanyl (OTFC) had a quicker onset to analgesia than oral immediate-release opioids. Intranasal fentanyl (INFS) had a quicker onset to analgesia than buccal tablets, which in turn had a quicker onset to analgesia than OTFC. Patient acceptance and global rating of efficacy were greater for INFS than for buccal fentanyl. OTFC and INFS have been used effectively to reduce acute pain in children who are opioid-naive. Abuse and addiction to OTFC, fentanyl buccal tablets and INFS was low, owing to patient selection.

Pharmacokinetics of fentanyl buccal tablet: a pooled analysis and review

Fentanyl buccal tablet (FBT) is indicated for the treatment of breakthrough pain in patients who are already receiving and are tolerant to opioid therapy for underlying, persistent cancer pain. FBT is designed to enhance the rate and efficiency of absorption of fentanyl through the buccal mucosa. FBT was shown to be dose proportional from 100 to 1,300 μg. This analysis provides an overview of the pharmacokinetic profile of FBT based on pooled data from nine pharmacokinetic studies. In all, 365 healthy non-opioid-tolerant adults receiving naltrexone were included in the analysis. Single-dose (100 to 1,300 μg) pharmacokinetic parameters were dose normalized to 100 μg. Pharmacokinetic measures included maximum observed plasma drug concentration (C(max)), plasma drug concentration versus time curve from time zero to infinity (AUC(0-∞)), time to reach C(max) (T(max)), apparent plasma terminal elimination rate constant, and elimination half-life. After FBT administration, fentanyl was rapidly absorbed, with T(max) ranging from 20 minutes to 4 hours postdose. Mean AUC(0-∞) was 1.49 ng•hour/mL, and mean C(max) was 0.237 ng/mL. However, plasma fentanyl concentration reached 80% of C(max) within 25 minutes and was maintained through 2 hours after administration. Based on the individual studies, bioequivalence was shown for sublingual and buccal tablet placement, and no significant effect of dwell time (duration of FBT presence in the oral cavity) was observed. The pharmacokinetic profile of FBT was characterized by rapid absorption, which is consistent with the rapid-onset efficacy profile of FBT observed in clinical studies.

Pharmacokinetics, safety, and tolerability of ascending doses of sublingual fentanyl, with and without naltrexone, in Japanese subjects

This open-label, nonrandomized study assessed single and repeat ascending doses of a new sublingual fentanyl (SLF) formulation in 48 healthy Japanese opiate-naïve subjects (47 completed). Subjects received single-dose SLF 100, 200, 400, or 800 µg followed by 13 doses 6 hourly, at their dose level. Subjects taking repeat-dose 400 and 800 µg were pretreated with naltrexone in order to block opiate-receptor-mediated effects on respiration, monitored by pulse oximetry and transcutaneous pco(2). Sublingual fentanyl was rapidly and consistently absorbed. After single doses, median t(first) was 0.08 to 0.25 hours and t(max) 0.50 to 1.00 hours. After repeat dosing, median t(max) (t(max,ss)) was 0.50 to 2.00 hours. Plasma concentrations were dose proportional both after single and repeat dosing, and naltrexone appeared to have no effect on SLF pharmacokinetics. Plasma fentanyl reached steady state within the 72-hour dosing period and accumulation was approximately 2-fold. After single doses, effects on respiratory variables were evident after the 400-µg and 800-µg doses. Transcutaneous pco(2) was not helpful in detecting respiratory depression. Thus, SLF yielded rapid absorption of fentanyl and dose-proportional plasma concentrations that, for 400 µg and 800 µg, were within the typical analgesic range. Respiratory depression in these opioid-naïve volunteers was manageable with simple clinical measures.

Fentanyl buccal tablet for the treatment of breakthrough pain: pharmacokinetics of buccal mucosa delivery and clinical efficacy

The treatment of breakthrough pain (BTP), a transitory exacerbation of pain that occurs on a background of otherwise-controlled, persistent pain, requires an opioid formulation and/or method of administration that can provide rapid and extensive systemic exposure. Fentanyl buccal tablet (FBT; FENTORA^®, Cephalon, Inc.) employs OraVescent^® drug delivery technology, which enhances the rate and extent of fentanyl absorption. OraVescent technology enhances the oral dissolution and buccal absorption of fentanyl, which facilitates rapid uptake of fentanyl into the bloodstream, reducing gastrointestinal absorption and minimizing extensive first-pass metabolism. The resulting pharmacokinetic profile of FBT is characterized by greater bioavailability and a higher early systemic exposure compared with the earlier oral transmucosal fentanyl citrate formulation. In clinical studies of opioid-tolerant patients with cancer-related and noncancer-related BTP, FBT has provided consistent and clinically relevant improvements in pain intensity and pain relief relative to placebo, with a safety and tolerability profile that is generally typical of that observed with other potent opioids. The pharmacokinetic properties of FBT allow for meaningful clinical efficacy, with an onset of action that closely matches the onset of BTP.

Formulations of fentanyl for the management of pain

Fentanyl is an opioid initially developed for parenteral administration. While oral administration is not an option due to a high first-pass metabolism, its high potency and lipophilicity have made a number of new routes of administration feasible. The transdermal therapeutic system offers an excellent option for long-term treatment of cancer and chronic pain, achieving stable plasma concentrations over the treatment period. The recent change from reservoir to matrix systems has made these systems more convenient to wear and safer to use, while being bioequivalent. In contrast, the patient-controlled iontophoretic transdermal system has been developed to enable on-demand delivery of transdermal bolus doses of fentanyl to treat postoperative pain. It offers a needle-free system to provide patient-controlled analgesia otherwise offered by intravenous pumps. However, due to technical difficulties the system is currently not clinically available. Oral transmucosal fentanyl utilizes the rapid uptake through the buccal mucosa to achieve high plasma concentrations rapidly and is indicated to treat breakthrough pain in patients who are not opioid-naive. The recently introduced fentanyl buccal tablets offer slightly better pharmacokinetics for the same indication. The intranasal route is another option to achieve rapid uptake of fentanyl, and is currently being investigated to provide acute and breakthrough pain relief. Transpulmonary administration of fentanyl remains experimental and this route of administration is not yet in clinical use. Overall, the specific pharmacological and physicochemical properties of fentanyl have made this compound highly suitable for novel routes of administration in a range of clinical indications.

Endogenous opiates and behavior: 2007

This paper is the thirtieth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2007 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses.

Relative Bioavailability of Fentanyl Following Various Dosing Regimens of Fentanyl Buccal Tablet in Healthy Japanese Volunteers

Background

Fentanyl buccal tablet (FBT; FENTORA®, Cephalon, Inc., Frazer, PA, USA) is indicated in the US for breakthrough pain in patients with cancer who are already receiving and are tolerant to around-the-clock opioid therapy for underlying persistent cancer pain. For each individual patient, FBT should be titrated to the effective dose.

Objective

The primary objective was to characterize the pharmacokinetic parameters of FBT 400 µg administered as a single 400 µg tablet (regimen A) or as two 200 µg tablets given simultaneously (regimen B) and determine whether these are bioequivalent in healthy Japanese volunteers. Regimen C (two 200 µg tablets 30 minutes apart) was also compared as a secondary objective.

Methods

Healthy Japanese adults received regimens A, B, and C in a crossover fashion. Naltrexone was given to minimize the opioid effects of fentanyl. Serum fentanyl concentrations were determined in venous blood collected through 36 hours post dose. Regimens were declared bioequivalent with respect to bioavailability (as reflected by AUC_0–∞, AUC_0–last, and C_max) if the 90% confidence interval (CI) of the regimens' ratio fell within 0.80–1.25 (80%–125%).

Results

Twenty-nine volunteers (13 men, 16 women) were enrolled; 24 completed the study. Regimens A and B had bioequivalent systemic exposure parameters (B/A [90% CI]: AUC_0–∞108.4 [103.4, 113.7], AUC_0–last 106.1 [100.7, 111.7], and C_max 92.3 [83.2, 102.4]). Regimen C was bioequivalent to both A and B for AUCs, but only to B for C_max. Median time to C_max was 45 minutes for regimen A and 60 minutes for regimens B and C. The most frequent AEs were dizziness, application-site erythema, headache, somnolence, nausea, and vomiting. All AEs were mild or moderate.

Conclusions

Bioavailability of fentanyl after FBT 400 µg administered as a single tablet was bioequivalent to that after 2 simultaneously administered 200 µg tablets in healthy Japanese volunteers. AEs were mild or moderate.

Dose Proportionality of Fentanyl Buccal Tablet in Healthy Japanese Volunteers

OBJECTIVE: This study was conducted to assess the dose proportionality, safety, and tolerability of fentanyl buccal tablet (FBT) in Japanese volunteers. METHODS: Healthy, opioid-naive Japanese adults received single-dose FBT 100, 200, 400, and 800 microg in a randomized, open-label, crossover fashion. Naltrexone was given to minimize the opioid effects of fentanyl. Peak serum fentanyl concentration (C(max)), time to C(max) (t(max)), area under the serum fentanyl concentration-time curve (AUC) from time 0 to infinity (AUC(0-infinity)), and AUC from 0 to the last quantifiable concentration (AUC(0-last)) were summarized using descriptive statistics. Dose proportionality was claimed if the ln-ln plots of C(max), AUC(0-infinity), and AUC(0-last) vs. dose were linear and the 90% confidence intervals (CI) of the slopes were within 0.8927 and 1.1073. The safety population comprised volunteers who received >/=1 FBT. RESULTS: Twenty-five volunteers were enrolled, 23 were included in the safety population (mean age 35.3 years), and 19 completed the study. The assessment of dose proportionality did not meet the statistical criteria (slope [90% CI]: 0.9118 [0.8601, 0.9635] for C(max), 1.0756 [1.0377, 1.1136] for AUC(0-infinity), and 1.0992 [1.0677, 1.1307] for AUC(0-last)). However, the increase in systemic exposure with dose appeared linear, and a post hoc analysis of partial AUCs from time 0 to 8, 12, 18, and 24 hours supported dose proportionality. Median t(max) of 90 minutes (range 30-180 minutes) was independent of dose. Adverse events (AEs) were mild or moderate. The most frequent AEs were nausea (N = 9), dizziness (N = 8), headache (N = 6), somnolence (N = 6), dyspepsia (N = 5), and vomiting (N = 3). No application-site or serious AEs were reported. CONCLUSIONS: Systemic exposure to FBT was approximately dose proportional across the range 100 microg to 800 microg in healthy Japanese adults. Adverse events were mild or moderate.

Extent of Fentanyl Accumulation Following Multiple Doses of Fentanyl Buccal Tablet 400 microg in Healthy Japanese Volunteers

Objective

This study was conducted to characterize the pharmacokinetics, including extent of accumulation, and safety and tolerability of fentanyl following multiple doses of fentanyl buccal tablet (FBT) in healthy Japanese volunteers.

Methods

Healthy Japanese adults received 10 successive doses of open-label FBT 400 µg at 6-hour intervals. Naltrexone was given to minimize the opioid effects of fentanyl. FBT was placed above a molar tooth between the gum and cheek. Peak serum fentanyl concentration (C_max), time to C_max (t_max), and area under the serum fentanyl concentration-time curve from 0 to 6 hours (AUC_0–6) were summarized using descriptive statistics. Accumulation ratio was calculated as C_max for dose 10/C_max for dose 1, and was calculated similarly for AUC_0–6.

Results

Fourteen volunteers (mean age 33 years) were enrolled, and 13 completed the study. After doses 1 and 10, respectively, mean (SD) C_max was 1.70 (0.49) ng/mL and 1.97 (0.42) ng/mL, AUC_0–6 was 4.46 (1.14) ng·h/mL and 6.81 (0.90) ng·h/mL, and median (range) t_max was 50 (30–110) minutes and 30 (15–120) minutes. Following 10 successive doses, systemic exposure (AUC_0–6) was 55% higher than after dose 1, and C_max was 23% higher. Steady state was achieved within 3 days of dosing at 6-hour intervals, i.e., prior to dose 10. The most frequent adverse events (AEs) were somnolence (N = 9), decreased oxygen saturation (N = 4), headache (N = 3), application-site pain (N = 8), application-site erythema (N = 6), and application-site reaction (N = 5). All AEs were mild or moderate.

Conclusions

Following administration of FBT at 6-hour intervals to healthy Japanese volunteers, at steady state, fentanyl exposure was higher by 55% (AUC_0–6) and 23% (C_max) than after a single dose of FBT. Adverse events were mild or moderate.

Effect of buccal dwell time on the pharmacokinetic profile of fentanyl buccal tablet

BACKGROUND

The time fentanyl buccal tablet (FBT) takes to completely dissolve after placement on the buccal mucosa (i.e., 'dwell time') could exceed the time to onset of analgesia.

OBJECTIVE

To examine the relationship between FBT dwell time and fentanyl pharmacokinetic parameters.

RESEARCH DESIGN AND METHODS

This was a post hoc exploratory analysis of data from two randomized, open-label, crossover, pharmaco-kinetic studies that were designed to assess dose proportionality within the anticipated therapeutic dose range. Healthy adults received single FBT doses of 200-1080 microg in Study 1 (n = 28) and 270-1300 microg in Study 2 (n = 42).

MAIN OUTCOME MEASURES

Assessments included buccal dwell time, defined as the duration of FBT presence in the oral cavity, and the following pharmacokinetic measures: maximum serum concentration (C(max)), time to C(max) (T(max)) and area under the concentration-time curve (AUC; exposure) from 0 minutes to median T(max) adjusted for the dose (T(max')) (AUC(0 T(max'))). Spontaneously reported adverse events were recorded.

RESULTS

Mean buccal dwell time for FBT across the dose range varied from 14 to 25 minutes (range 3 - 62 minutes). There was no evidence of an association between FBT dwell time and values for T(max) (medians 45 - 60 minutes), dose-normalized C(max) (means 0.42-0.66 pg/ml/200 microg) or dose-normalized AUC(0 T(max')) (means 0.24-0.38 pg x h/ml/200 microg) over the range of FBT doses delivered. All adverse events reported were mild to moderate; none were unexpected or serious.

CONCLUSION

The pharmacokinetic parameters of FBT did not appear to be related to its buccal dwell time.

Fentanyl buccal tablet: faster rescue analgesia for breakthrough pain?

Breakthrough pain (BTP) is an unmet clinical need that is still poorly diagnosed, evaluated and inadequately treated. The prevalence of BTP has been estimated to affect at least 64% of cancer patients. Two pain-relief strategies were proposed: preventive and active ('rescue'). Oral short-acting opioid seems to be the most popular approach for BTP treatment, however, it is likely to be inadequate for a substantial proportion of patients as a result of the slow-onset of most available opioid preparations. Fentanyl buccal tablet (FBT) is a novel delivery system for fentanyl citrate. FBT utilizes OraVescent technology to improve bioavailability and speed of drug delivery. Recent studies have demonstrated superior pharmacokinetic profiles when compared with other available transmucosal opioids (OTFC), however, pharmacodynamic data are still somewhat limited.