Intranasal administration of opioids/fentanyl – Physiological and pharmacological aspects

Abstract

Intranasal opioid formulations have been investigated as a new route of administration that may offer a rapid onset and short duration of analgesic effect. These characteristics are required for the optimal treatment of certain types of pain, e.g., breakthrough cancer pain, such that the temporal characteristics of the analgesic effect mirror those of the pain episode itself. The nasal cavity is highly perfused with permeable capillaries and is well suited for rapid drug uptake, however, challenges to intranasal administration are the small drug volume required to avoid run-off into the pharynx, and the short time window for absorption before the drug is removed from the nose via mucociliary clearance. Potent opioids, such as fentanyl, have the possibility of low administration volumes and are the best candidates for intranasal administration. Intranasal fentanyl spray (INFS) showed promising pharmacokinetic characteristics (such as a T max of 13 min) compared with other fentanyl formulations, and has a short duration of effect. These findings are supported by clinical evidence indicating that INFS is an effective treatment of breakthrough cancer pain, providing a rapid onset of analgesia, with a convenient method of administration.