Opioids for breakthrough cancer pain In BTCP which is gradual onset (approximately 30 minutes) and lasts longer than one hour, standard immediate release opioid preparations (eg, oral
morphine) are sufficient. In BTCP which is rapid onset (5–10 minutes) and short duration (less than 60 minutes), fentanyl is a good choice of opioid. A number of preparations exist which are either absorbed through the nasal or oral mucosa. Due to it being lipophilic, it is rapidly absorbed through the oral or nasal mucosa enabling it to have a quick onset of action.Fentanyl preparations specifically developed for BTCP exist in several preparations including a lozenge, a soluble film, a buccal tablet, and a nasal spray. There is a lack of evidence comparing fentanyl products for BTCP and there is no consensus on the correct dose when prescribing rapid acting opioids for BTCP.28 Each fentanyl product should be titrated to the most effective dose that provides adequate analgesia with minimal side effects.