Can I take a medication for nausea if I use Fentora?

You can use Fentora (fentanyl), a morphine-like drug for breakthrough cancer pain, if you're on a medication for nausea, but your doctor is likely to monitor the painkiller's dosage very carefully. Certain antinausea medicines, such as aprepitant, can cause a dangerous buildup of fentanyl -- Fentora's active ingredient -- in your body, increasing the risk of a fatal overdose. You and your doctor should be on the lookout for signs that your levels are rising, such as increased sleepiness or a sighing pattern of breathing (in which a deep breath is followed by a long pause), especially whenever your dose of Fentora or your antinausea medicine is changed.