Fentanyl: Side Effects, Uses & Monitoring
Fentanyl transdermal system is indicated for the management of pain in opioid-tolerant patients, severe enough to require daily, around-the-clock, long- term opioid treatment and for which alternative treatment options a
- Data source
- FDA labeling via NIH DailyMed (label 51ed4fe8…)
- Label version
- current
- Last reviewed
- 2026
Reported adverse reactions
Reactions listed in current FDA labeling, with the highest frequency reported across summarized placebo-controlled trials.
| Adverse reaction (as reported in labeling) | Reported frequency* |
|---|---|
| Nausea | 41% |
| Vomiting | 26% |
| Somnolence | 19% |
| Headache | 12% |
| Dizziness | 10% |
| Insomnia | 10% |
| Diarrhea | 10% |
| Constipation | 9% |
| Fatigue | 6% |
| Feeling cold | 6% |
| Hyperhidrosis | 6% |
| Anorexia | 5% |
| Palpitations | 4% |
| Malaise | 4% |
| Muscle spasms | 4% |
| Abdominal pain upper | 3% |
| Pruritus | 3% |
| Abdominal pain | 3% |
| Tremor | 3% |
| Anxiety | 3% |
*Highest percentage reported for the active moiety across placebo-controlled trial tables in current FDA labeling. Values reflect trial reporting, not your individual risk.
Labeled uses (from FDA prescribing information)
Fentanyl transdermal system is indicated for the management of pain in opioid-tolerant patients, severe enough to require daily, around-the-clock, long- term opioid treatment and for which alternative treatment options are inadequate. Patients considered opioid-tolerant are those who are taking, for one week or longer, at least 60 mg of morphine daily, or at least 30 mg of oral oxycodone daily, or at least 8 mg of oral hydromorphone daily, or an equianalgesic dose of another opioid. Limitations of Use Because of the risks of addiction, abuse, and misuse with opioids, even at recommended doses, and because of the greater risks of overdose and death with extended-release opioid formulations, reserve fentanyl transdermal system for use in patients for whom alternative treatment options (e.g., non-opioid analgesics or immediate-release opioids) are ineffective, not tolerated, or would be otherwise inadequate to provide sufficient management of pain.
Frequently Asked Questions
What is Fentanyl used for?
FDA labeling lists the approved uses shown above under "Labeled uses." This summary is informational; only a qualified prescriber can determine whether a medication is appropriate for you.
What are the most commonly reported side effects of Fentanyl?
The table above shows adverse reactions and the highest frequencies reported in placebo-controlled trials summarized in current FDA labeling for Fentanyl. Individual risk varies.
Does Fentanyl require lab monitoring?
Monitoring needs vary. Ask your healthcare provider whether any lab tests apply while taking Fentanyl.
Where does this information come from?
All clinical facts on this page were extracted from the current FDA-registered product labeling for this ingredient, published by manufacturers through NIH DailyMed. See the source link below.
Medical disclaimer: Educational content extracted from public FDA labeling. Not medical advice. Always consult a qualified healthcare professional before starting, stopping, or changing any medication.