Drug interactions including alcohol and other CNS depressants potentiate effects. MAOIs may precipitate hypertensive crisis.

The Onset/Peak/Duration for OTFC is 15-60 sec (<transmucosal)/20 sec to 4 min/1-2 hr).

As a result of the altered level of consciousness noted with opioids, casualties should be disarmed after being given fentanyl, regardless of the route of administration. Additionally, you should document a mental status exam using the AVPU (Alert, Verbal, Pain, Unresponsive) method prior to administering fentanyl and use caution in casualties with eye injuries or mild TBI as fentanyl may make it difficult to perform a neurologic exam or determine if the casualty is decompensating. 

Be sure to monitor the casualty’s airway, breathing, and circulation closely after fentanyl administration. If there are any signs to suggest that the casualty is experiencing side effects from excess fentanyl, immediately administer naloxone to reverse the effects. Polypharmacy is not recommended; benzodiazepines should NOT be used in conjunction with opioid analgesia. 

OTFC is a valuable option because it provides potent, rapid analgesia without requiring IV access. Starting an IV just for analgesia is not optimal because:

Several studies have been performed over the last decade or two to validate the success and safety of using OTFC. In one study, 800 mcg OTFC produced similar relief and durations of analgesia as 10 mg IV morphine. Other studies have demonstrated equivalent pain relief scores from battlefield casualties when compared to morphine, validating its efficacy. From a safety perspective, one of the larger studies looked at 286 casualties who received OTFC and there was only one major adverse reaction in a casualty who not only received twice the recommended OTFC dose but also received morphine. No one receiving the recommended dose had any significant adverse outcomes.

Remember, the goal of analgesia is to reduce pain to a tolerable level while still protecting their airway and mentation.