Fentanyl, a strong opioid, was first used in an injectable form, and later as patches. Since 2002, it has also been available in forms which are rapidly absorbed via the buccal mucosa (Actiq° or other brands) or nasal mucosa (Instanyl° or other brands). These fast-acting formulations are intended for treatment of breakthrough pain in patients who are already receiving maintenance opioid treatment for chronic cancer pain.

A national monitoring study in France examined dependence and overdose relating to fast-acting fentanyl between 2016 and 2019. Many of the cases reported concerned patients who had pain due to causes other than cancer, especially rheumatological or neuropathic pain. 155 patients exhibited dependence on fentanyl, and in 79% of these patients, there were serious consequences including 1 death.

176 of the reports analysed mentioned an adverse effect linked to the rapid onset of the opioid effects of fentanyl, including 7 cases of coma and 10 of respiratory depression. Two-thirds of the 42 cases of overdose involved patients who did not have cancer. 36 cases of overdose were unintentional: 17 were linked to prescription of an excessive dose, 9 to administration of an excessive dose by patients or healthcare professionals. 7 patients died from an overdose.

Fast-acting forms of fentanyl administered by the buccal or nasal mucosal route should be used with caution because of the intensity and rapidity of the opioid effects. Patients should be thoroughly informed of the risk of dependence and (sometimes fatal) overdose with fentanyl, and naloxone, an antidote, should be routinely prescribed so that the patients themselves, or their families or carers, can act rapidly in case of overdose. It is important to explain how to use this antidote and to make sure that this has been fully understood.

©Prescrire 1 April 2022

Source: "Fast-acting fentanyl: overdose and dependence" Prescrire International 2022; 31 (236): 106. Subscribers only.

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