Fentanyl is now available in a nasal spray for the management of “breakthroughs” in adults on maintenance opioid therapy for chronic cancer pain.
PecFent® contains pectin which forms a gel on contact with calcium in the nasal mucosa, from which the fentanyl is rapidly absorbed, where Instanyl® (recently registered) is simply an aqueous solution.
Their median time to full effect is around 15 minutes, but pharmacokinetics are highly variable, and doses should be individualised. Equianalgesic doses should not be used when transferring from another opioid or fentanyl product (it undergoes first pass metabolism). Titrate up from the lowest available dose at two-hourly intervals with a single spray into first one, then two nostrils. If breakthrough pain occurs more than four times a day, the maintenance opioid should be reviewed.
Absorption may be decreased if used with nasal decongestant sprays. Cytochrome P450 3A4 metabolism means that coadministration with inducers may reduce (and inhibitors may increase) fentanyl plasma concentrations.
It should be used with caution in patients with head injuries, increased intracranial pressure, bradyarrhythmias, hypovolaemia, hypotension, those at risk of respiratory depression, or taking monamine oxidase inhibitors.