Non-traditional administration of remifentanil in an experimental setting.

Remifentanil is ultrashort-acting opioid with a unique pharmacokinetic profile. It is used exclusively intravenously. While considering its rapid onset of action and other pharmacokinetic properties, we decided to assess its effects following administration via non-traditional routes. Rabbits (n=10 per each group) were randomized into six groups: remifentanil 1 microg/kg and 3 microg/kg IM, 5.0 and 10.0 microg/kg conjunctivally, and 10 microg/kg and 25.0 microg/kg intranasally. Sedating effects were assessed via a loss of the righting reflex. Secondary, mean arterial blood pressure, arterial oxygen saturation of hemoglobin, and pulse rate was monitored in all rabbits. Non-traditional routes of administration were shown to provide a rapid onset of action as well as fast recovery. Importantly, the administration of remifentanil did not result in any deterioration of cardiovascular functions.