Fentanyl (transdermal route) - Side effects & dosage - Mayo Clinic
Shallow, slow, or difficult breathing.
Avoid exposing the patch to direct heat (heating pads, saunas, hot tubs), as increased body temperature can cause the patch to release fentanyl too quickly into the bloodstream. Fentanyl Transdermal Patch Side Effects
Do not consume alcohol or other sedatives, as these can dangerously increase the risk of fatal respiratory depression. Fentanyl (transdermal route) - Side effects & dosage