Types of Side Effects

Though unpleasant, the most common side effects of fentanyl are not likely to cause long-term health complications. These side effects include nausea, vomiting, constipation, dry mouth, drowsiness, confusion, weakness and sweating.

Drug Interactions

A number of drugs increase the risk of side effects from fentanyl, including the antiretroviral drug ritonavir, the anti-fungal medications ketoconazole and itraconazole, antibiotics such as troleandomycin and clarithromycin and the antidepressant nefazodone, according to the U.S. National Library of Medicine. In addition, fentanyl should not be taken with other drugs that slow down the nervous system, such as alcohol, sedatives, tranquilizers, anesthetics, muscle relaxants and monoamine oxidase inhibitors (MAOIs).

Risks

Fentanyl poses a risk of respiratory depression, a life-threatening condition in which the brain is unable to properly regulate breathing, warns the U.S. National Library of Medicine. Other risks associated with fentanyl include arrhythmia, amnesia, paranoia and hallucinations.

Addiction

Fentanyl also poses a risk of chemical dependence, particularly when used for several weeks at a time. Once dependence develops, discontinuing use of the drug may cause symptoms of withdrawal such as anxiety, agitation, muscle aches, abdominal cramps, diarrhea and shivering, according to Penn State University.

Considerations

Because its effects on fetal development are unknown, doctors rarely prescribe fentanyl to pregnant women. If you have a history of chemical dependence, hypothyroidism, mental illness, prostate enlargement, head injury, gallbladder or heart disease, intestinal disorders, inflammation of the pancreas, lung disease, asthma, respiratory depression, kidney or liver disease or intestinal blockages, then you should not take fentanyl, cautions the Mayo Clinic.

Source:

DailyMed: Duragesic (Fentanyl) Patch

Mayoclinic.com: Fentanyl (Transdermal Route)

Penn State University: Opiate Withdrawal