Formulations of fentanyl for the management of pain

Comparing the administration of fentanyl 1 µg kg⁻¹ and fentanyl 0.5 µg kg⁻¹ in dilation and curettage procedures

PURPOSE

This study was carried out to compare fentanyl 0.5 µg kg⁻¹ -propofol as opposed to fentanyl 1 µg kg⁻¹ -propofol in terms of providing adequate analgesia, and a comparable recovery profile in dilation and curettage (D&C) procedures.

METHODS

Verbal Pain Scale (VPS) scores, modified Aldrete scores, and hemodynamic parameters were recorded during and after the surgical procedure. In addition, a record was also kept of adverse events, and patients and surgeons were questioned about their satisfaction with the anesthesia.

RESULTS

No difference was found between the two groups in terms of hemodynamic parameters, the VPS scores, or patient and surgeon satisfaction. The fentanyl 0.5 µg group displayed significantly higher modified Aldrete scores at both 5- and 10-min postoperative. Adverse events in both groups were considerably few. The incidence of postoperative nausea and vomiting (PONV) in the fentanyl 0.5 µg group was lower eventhough it did not reach the statistically significance level. In addition, faster recovery times were recorded with the administration of fentanyl 0.5 µg kg⁻¹ .

CONCLUSION

Fentanyl 0.5 µg kg⁻¹ appears to be as reliable as that of fentanyl 1 µg kg⁻¹ with faster recovery times when used in D&C procedures.

Development of in vitro models to demonstrate the ability of PecSys®, an in situ nasal gelling technology, to reduce nasal run-off and drip

Many of the increasing number of intranasal products available for either local or systemic action can be considered sub-optimal, most notably where nasal drip or run-off give rise to discomfort/tolerability issues or reduced/variable efficacy. PecSys, an in situ gelling technology, contains low methoxy (LM) pectin which gels due to interaction with calcium ions present in nasal fluid. PecSys is designed to spray readily, only forming a gel on contact with the mucosal surface. The present study employed two in vitro models to confirm that gelling translates into a reduced potential for drip/run-off: (i) Using an inclined TLC plate treated with a simulated nasal electrolyte solution (SNES), mean drip length [±SD, n = 10] was consistently much shorter for PecSys (1.5 ± 0.4 cm) than non-gelling control (5.8 ± 1.6 cm); (ii) When PecSys was sprayed into a human nasal cavity cast model coated with a substrate containing a physiologically relevant concentration of calcium, PecSys solution was retained at the site of initial deposition with minimal redistribution, and no evidence of run-off/drip anteriorly or down the throat. In contrast, non-gelling control was significantly more mobile and consistently redistributed with run-off towards the throat.

Conclusion

In both models PecSys significantly reduced the potential for run-off/drip ensuring that more solution remained at the deposition site. In vivo, this enhancement of retention will provide optimum patient acceptability, modulate drug absorption and maximize the ability of drugs to be absorbed across the nasal mucosa and thus reduce variability in drug delivery.

Intranasal drug delivery: an efficient and non-invasive route for systemic administration: focus on opioids

Intranasal administration is a non-invasive route for drug delivery, which is widely used for the local treatment of rhinitis or nasal polyposis. Since drugs can be absorbed into the systemic circulation through the nasal mucosa, this route may also be used in a range of acute or chronic conditions requiring considerable systemic exposure. Indeed, it offers advantages such as ease of administration, rapid onset of action, and avoidance of first-pass metabolism, which consequently offers for example an interesting alternative to intravenous, subcutaneous, oral transmucosal, oral or rectal administration in the management of pain with opioids. Given these indisputable interests, fentanyl-containing formulations have been recently approved and marketed for the treatment of breakthrough cancer pain. This review will outline the relevant aspects of the therapeutic interest and limits of intranasal delivery of drugs, with a special focus on opioids, together with an in-depth discussion of the physiological characteristics of the nasal cavity as well as physicochemical properties (lipophilicity, molecular weight, ionisation) and pharmaceutical factors (absorption enhancers, devices for application) that should be considered for the development of nasal drugs.

An update in options for the treatment of pain: a review of new opioid formulations

In the past 2 decades, there has been a significant increase in the use of opioids for the management of chronic nonmalignant pain. This increase in usage has led to concerns of misuse and abuse of opioids. Also, many of the available opioid options were previously only available as oral tablets or capsules, further limiting treatment options for health care providers. Several new opioid formulations have been developed to address and prevent the misuse and abuse of opioids via tampering in the United States. In addition, alternative delivery systems have been developed to provide physicians with more options to provide adequate pain management for those with chronic pain. This article reviews new opioid options for the treatment of pain management and requirements of the Risk Evaluation and Mitigation Strategies program.

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.

Fentanyl buccal tablets for the treatment of breakthrough pain

SUMMARY Fentanyl buccal tablets (FBT) have been designed to treat breakthrough pain (BTP) in patients who are already receiving, and who are tolerant to, opioid therapy for their underlying persistent pain. FBT are a formulation that uses an effervescent drug delivery system to enhance penetration across the buccal mucosa. OraVescent technology provides an effervescent reaction that liberates carbon dioxide in the buccal cavity. This reaction causes an initial decrease in pH, which facilitates solubilization, thus driving fentanyl into solution. Subsequently, carbon dioxide increases the local pH, which facilitates permeation of unionised fentanyl across the buccal mucosa. In clinical studies of opioid-tolerant patients with cancer and noncancer-related BTP, FBT have provided consistent and clinically relevant improvements in pain intensity and pain relief relative to placebo and oral opioids like oxycodone. The safety and tolerability profile is generally typical of that observed with other opioids. The pharmacokinetic properties of FBT allow for a meaningful clinical efficacy, with an onset of action that closely matches the onset of BTP. FBT, as with any other transmucosal preparations of fentanyl, should not be used in patients who are not opioid-tolerant.

Intranasal fentanyl for pain management in children: a systematic review of the literature

Intranasally administered fentanyl (INF) has been studied as an alternate route of delivery for pain relief in children. The purpose of this systematic review is to evaluate the available research evidence on the use of INF in the pediatric population. A search was conducted of PubMed, ISI, Scopus, Popline, CINAHL, and Embase for research studies evaluating INF in this population (0-18 years of age). The studies were graded on the strength of the evidence and the results reviewed. All of the reviewed studies showed similar or improved pain scores when compared with other opioids and administration methods. No severe adverse outcomes were reported. Current evidence suggests that INF is a safe and effective method of pain management for children in a variety of clinical settings.

Intra- and interindividual variabilities in the pharmacokinetics of fentanyl buccal soluble film in healthy subjects: a cross-study analysis

BACKGROUND AND OBJECTIVE

Breakthrough pain describes transient exacerbations of pain that occur in cancer patients with adequately controlled background pain. Transmucosal fentanyl administration produces rapid-onset and short-duration analgesia that is effective for treating patients with breakthrough pain. Although a significant amount of research has been devoted to the study of speed of analgesia onset of transmucosal fentanyl products, few data exist on their variability in absorption, particularly within the same individual, despite the importance of this characteristic to the dose-to-dose reliability of their analgesic effect. This cross-study analysis aimed to evaluate the intra- and interindividual pharmacokinetic differences of fentanyl administered via fentanyl buccal soluble film in healthy subjects.

METHODS

Data were evaluated from 24 subjects in two pharmacokinetic studies of fentanyl administered via fentanyl buccal soluble film (Breakyl®/Onsolis™; BEMA® [BioErodible MucoAdhesive] technology). In one study, 12 healthy subjects received 600 μg doses of fentanyl as single film on two separate occasions; in the second study, 12 different healthy subjects received 800 μg doses of fentanyl on two separate occasions, one as a single 800 μg film and the other as four 200 μg films.

RESULTS

The analysis showed a minimal intraindividual variability and a relatively higher interindividual variability in pharmacokinetic parameters (i.e. maximum plasma concentration, area under the plasma concentration-time curve from time zero to infinity). The coefficient of variation for intraindividual exposure to fentanyl variability was 7-10%, and for interindividual variability was 23-39%.

CONCLUSION

The minimal intraindividual variability in fentanyl absorption from the buccal soluble film demonstrates a predictable dose-to-dose exposure, which is a very desirable attribute for a medicine that is intended to treat breakthrough cancer pain, suggesting that this product would be expected to produce consistent effects in clinical practice. The greater interindividual variability highlights the need for individual titration of this product (as occurs with similar transmucosal fentanyl products), and for the availability of an adequately wide dose range.

Fentanyl pectin nasal spray: in breakthrough pain in opioid-tolerant adults with cancer

Fentanyl pectin nasal spray (PecFent®) uses a novel pectin-based delivery system that turns from an aqueous solution into a gel when applied to mucosal surfaces. Fentanyl is absorbed in a controlled manner from the pectin gel formed in the nasal cavity, and has a rapid onset of pain relief and duration of action that matches the time course of a typical episode of breakthrough pain in cancer (BTPc). Relative to administration as oral transmucosal fentanyl, fentanyl administered as fentanyl pectin nasal spray is more rapidly absorbed, reaches higher maximum plasma concentrations and has greater bioavailability. In the treatment of BTPc in two randomized, double-blind, crossover trials in opioid-tolerant adults, fentanyl pectin nasal spray (100-800 μg titrated doses) was significantly more effective than placebo in reducing pain intensity and provided a significantly faster onset of pain relief than oral immediate-release morphine. During long-term treatment of BTPc episodes, fentanyl pectin nasal spray consistently provided effective pain relief in an open-label, 16-week trial. Most patients were satisfied or very satisfied with the ease of use and convenience of the nasal spray. Fentanyl pectin nasal spray 100-800 μg was generally well tolerated and was not associated with nasal tolerability problems.

Intranasal fentanyl for pain control: current status with a focus on patient considerations

Of several newer delivery systems under development and investigation for the administration of opioids, the intranasal route has received a substantial amount of attention. Intranasal administration is a convenient form of delivery that is applicable to several opioids. It has the potential for self-administration, combined with a rapid onset of action, allowing for patient-controlled analgesia. In clinical practice, intranasal administration has been found to be a reliable drug delivery method that is familiar to patients. Intranasal opioids have proven to be useful in both in-hospital and out-of-hospital pain management settings. Fentanyl, a highly lipophilic step 3 opioid, has been evaluated for intranasal administration. The purpose of this review is to examine the role of the nasal route of opioid administration and examine the evidence base for the use of fentanyl intranasally.

Fentanyl sublingual: in breakthrough pain in opioid-tolerant adults with cancer

Fentanyl is a potent opioid with a short duration of action. Fentanyl sublingual has been formulated as a rapidly disintegrating tablet that is quickly absorbed, producing a fast onset of analgesia. In two randomized, double-blind clinical trials, fentanyl sublingual as single fixed or titrated doses reduced pain intensity during breakthrough pain episodes to a significantly greater extent than placebo in opioid-tolerant cancer patients. In a fixed-dose phase II trial and a titrated-dose phase III trial, fentanyl sublingual (as a single 400 μg dose and as titrated doses) reduced mean pain intensity difference (PID) to a significantly greater extent than placebo over the entire treatment period (up to 60 minutes), reaching statistical significance 15 minutes post-dose. In the titrated-dose study, the mean sum of PID (area under the PID vs time curve) at 30 minutes post-dose was significantly greater with fentanyl sublingual than placebo, with significant improvements in PID seen at 10 minutes maintained at 60 minutes post-dose. In the phase III study, patients receiving fentanyl sublingual were more satisfied with their treatment than patients receiving placebo (measured using the Patient Global Evaluation of Medication score), and almost half of all fentanyl sublingual recipients were satisfied or very satisfied with their treatment. Fentanyl sublingual was generally well tolerated in the two trials and most adverse events were mild to moderate in intensity.

Effects of chronic fentanyl administration on physical performance of aged rats

There is growing concern over the increasing use of opioids to treat chronic pain in the elderly primarily because of the potential increased sensitivity to the adverse side effects. Here, we use a preclinical model (male Brown Norway X F344 rats aged 12, 18, 24, and 30 months) to describe the outcome of chronic fentanyl administration (1.0mg/kg/day) on various physiological and behavioral measures. Continuous fentanyl administration resulted in an initial decrease in food consumption, followed by the development of tolerance to this effect over a 4-week period and a subsequent increase in food consumption during withdrawal. This change in food consumption was associated with decreases in body weight (predominantly due to a loss of fat mass) that was maintained through early withdrawal. After 1 month of withdrawal, only the 12-month old animals had fully regained body weight. Fentanyl administration resulted in a decrease in grip strength and an increase in locomotor activity that did not differ across age groups. There was no effect of fentanyl administration on rotarod performance. These results demonstrate that while there is a delayed recovery of body mass with age, the observed changes in behavioral responses are uniform across ages.

Management of cancer pain

In the last decades, studies validating the WHO analgesic ladder have been shown to have methodological limitations and different problems are unresolved due to a lack of controlled studies on this subject. These problems include a better definition of the role of NSAIDs, the prolonged use of NSAIDs in cancer pain, and the utility of step 2. Moreover, the indications for using different strong opioids and alternate routes of administration to improve pain relief in difficult pain situations are not well established. The proportion of patients who do not benefit from these treatments remain unclear, and how the opioid response may be improved with the use of adjuvants is also uncertain. This review will offer an update on these problems and the existing therapeutic opportunities.