Pharmacokinetic Profile of Fentanyl in the Koala (Phascolarctos cinereus) after Intravenous Administration, and Absorption via a Transdermal Patch

Fentanyl was administered as a single intravenous bolus injection at 5 µg/kg to five koalas and fentanyl plasma concentrations for a minimum of 2 h were quantified by an enzyme-linked immunosorbent assay (ELISA). The median (range) fentanyl elimination half-life and clearance were 0.53 (0.38–0.91) h, and 10.01 (7.03–11.69) L/kg/h, respectively. Assuming an analgesic therapeutic plasma concentration of 0.23 ng/mL (extrapolated from human studies), an intravenous constant infusion rate was estimated at approximately between 1.7 to 2.7 µg/kg/h (using the clearance 95% confidence intervals). A transdermal fentanyl patch was applied to the antebrachium of an additional two koalas for 72 h. Fentanyl plasma concentrations were determined during the patch application and after patch removal at 80 h. The fentanyl plasma concentration was greater than 0.23 ng/mL after 12 to 16 h. While the patch was applied, the maximum fentanyl concentration was approximately 0.7 ng/mL from 32 to 72 h. Fentanyl plasma concentrations increased to 0.89 ng/mL 1 h after the patch was removed, and then decreased to a mean of 0.47 ng/mL at 80 h. The transdermal fentanyl patch is likely to provide some level of analgesia but should be initially co-administered with another faster acting analgesic for the first 12 h.

Acute Cytotoxic Cerebellar Edema Subsequent to Fentanyl Patch Intoxication in an Infant

The opioid epidemic continues to have devastating consequences for children and families across the United States with rising prevalence of opioid use and abuse. Given the ease of access to these medications, accidental ingestion and overdose by children are becoming increasingly more common. The recognition of opioid-induced neurotoxicity and the associated life-threatening complication of acute cerebellar cytotoxic edema are crucial, as are the high morbidity and mortality without timely intervention. We discuss an infant with acute cytotoxic cerebellar edema following mucosal exposure to a transdermal fentanyl patch.

Case Report: Intoxication in a Pig (Sus Scrofa Domesticus) After Transdermal Fentanyl Patch Ingestion

An experimental study on the effects of electroporation on pancreatic tissue was performed in pigs, and the fentanyl transdermal patch (FTP) was used postoperatively as part of multimodal pain management. Ingestion of an FTP, which resulted in fentanyl intoxication, was suspected 5 days after placement in one of the experimental pigs. The pig was first dysphoric, running in the stall, panting and vocalizing until it finally became depressed and it remained lying on the floor. Ingestion of an FTP was not observed but the fentanyl plasma concentration on the day of intoxication was 20.7 ng/ml, while at its peak after FTP administration it was only 0.492 ng/ml. The intoxication was successfully treated with a single intramuscular naloxone injection.

Transdermal Fentanyl patch: An approach to enhance tolerance of conscious proning in COVID-19 patients

The COVID-19 ARDS appears to have worse outcomes than ARDS from other causes. It is a predictable serious complication and the key strategy is to maintain oxygenation. Adopting the prone position for conscious COVID-19 patients requiring basic respiratory support, is shown to benefit patients in terms of improving oxygenation, reducing the need for invasive ventilation and potentially even reducing mortality. Cough and myalgia are the common and most distressing symptoms seen in conscious COVID-19 patients which can impair tolerance to awake proning. Modified awake proning with application of transdermal fentanyl patch (TFP) can improve the compliance to conscious proning in COVID-19 patients.

Opioid rotation from transdermal fentanyl to continuous subcutaneous hydromorphone in a cachectic patient: A case report and review of the literature

Opioid rotation from transdermal fentanyl to an alternate opioid is often necessitated in advanced disease, but is fraught with uncertainty due to variable absorption from the patch in end-stage illness and the lack of a clearly established opioid rotation ratio. The manufacturer of transdermal fentanyl provides opioid rotation recommendations only for rotation from the oral morphine equivalent daily dose (MEDD) of opioid to the patch, not in the opposite direction. This is a case report of a single patient with cancer and cachexia admitted to the palliative care unit of a large academic medical centre in Canada. The patient is a 50-year-old female with widely metastatic breast cancer who developed opioid toxicity when maintenance transdermal fentanyl patch therapy (100 μg patch applied every 72 h) was rotated to subcutaneous hydromorphone infusion to improve pain control. Hydromorphone was initiated at a rate of 1 mg/h by continuous infusion based on an opioid rotation ratio for transdermal fentanyl (μg/h):MEDD (mg/day) of 1:2.4. Opioid toxicity eventually resolved with downward titration of hydromorphone to only 30% of the initially estimated equianalgesic dose. This case highlights the need for close follow-up of all patients undergoing opioid rotation from transdermal fentanyl and reinforces the need to reduce the initial dose of the new opioid by 30%–50% of the calculated MEDD, especially when rotating from a high dose of transdermal fentanyl, or if there are factors potentially impairing absorption from the patch such as age, cachexia and weight loss, or if rotation is performed for reasons other than uncontrolled pain.

TRANSDERMAL FENTANYL PATCH FOR ACUTE PAIN CONTROL AFTER SHORT INTRAHOSPITAL STAY

Transdermal fentanyl patch (TFP) is used for alleviation of chronic pain, while scientific evidence regarding its use for acute pain is insufficient. Purpose. To compare the effects of pain control by non-steroidal anti-inflammatory drug (NSAID) and TFP and the restrictions in daily activities in patients following elective minor surgical interventions. Patients and methods. Prospective, randomised, casecontrolled study included patients aged ≥18 years who underwent elective cholecystectomy, gastric fundoplication or inguinal hernia repair. All randomised patients (fentanyl prescription group, FG, and control group, CG, 62 cases each) were administered dressing plasters for the first three post-operative days; the FG patients received 50mcg/h TFP under the plaster. Within the 4 post-operative days, the patients of both groups received diclofenac on demand. Post-operative pain at rest and during movement was evaluated using the Visual Analogue Scale on the 1st, 2nd, 3rd, 4th post-operative days. Daily activities using the Functional Activity Score were scored as 0 – no limitations, 1 – some limitations, 2 – severe limitations. Results. Pain both at rest and during movement on the first three post-operative days was lower in the FG; CG patients received 5 times more doses of diclofenac on demand on the 1st day after the surgery, with the higher need of NSAID during the next two days (p<0.05). The total number of NSAID doses per patient administered on demand was 3.11±0.59 in the CG and 0.73±0.16 in the FG (p<0.05). The influence of pain on daily activities on the 2nd post-operative day was scored as 0 by 92% patients and as 1 by 8% patients of the FG, versus 60% and 40% patients of the CG (p<0.05). Conclusion. Patients with TFP experienced significantly more effective pain control leading to less restricted daily activities and used less doses of NSAID within the first few post-operative days. Plain Language Summary. Could a single long-lasting dose of transdermal fentanyl patch serve as an alternative to uncontrolled consumption of non-steroid anti-inflammatory drugs when dealing with early post-operative pain in patients following a hospital discharge after an elective minor surgery? Our conclusion suggests that the answer is “yes”, if the riskbenefits balance is evaluated.