Fentanyl Transdermal System Side Effects

Generic name: fentanyl

Medically reviewed by Drugs.com. Last updated on Mar 14, 2025.

Note: This document provides detailed information about Fentanyl Transdermal System Side Effects associated with fentanyl. Some dosage forms listed on this page may not apply specifically to the brand name Fentanyl Transdermal System.

Applies to fentanyl: lozenge/troche, spray, tablet.

Other dosage forms:

• injection solution
• nasal spray
• transdermal patch extended release

Precautions

It is very important that your doctor check your progress at regular visits. This will allow your doctor to see if the medicine is working properly and to decide if you should continue to take it.

Do not use this medicine for minor aches and pains (eg, headaches, migraines) or after surgery or injuries.

Do not use this medicine if you have taken a monoamine oxidase (MAOI) inhibitor (eg, isocarboxazid phenelzine, selegiline, tranylcypromine, Eldepryl®, Marplan®, Nardil®, or Parnate®) in the past 2 weeks.

Using this medicine while you are pregnant may cause serious unwanted effects in your newborn baby. Tell your doctor right away if you think you are pregnant or if you plan to become pregnant while using this medicine.

Fentanyl is a medicine that can harm or cause death to a child. Patients and caregivers should keep this medicine out of the reach of children. Carefully dispose of any partially used units or unused medicine properly.

This medicine may be habit-forming. If you feel that the medicine is not working as well, do not use more than your prescribed dose. Call your doctor for instructions.

This medicine will add to the effects of alcohol and other central nervous system (CNS) depressants. CNS depressants are medicines that slow down the nervous system, which may cause drowsiness or make you less alert. This effect may last for a few days after you stop using this medicine. Some examples of CNS depressants are antihistamines or medicine for hay fever, allergies, or colds, sedatives, tranquilizers, benzodiazepines, other prescription pain medicine or narcotics, barbiturates or seizure medicines, muscle relaxants, or anesthetics (numbing medicines), including some dental anesthetics. Check with your doctor before taking any of the medicines listed above while you are using this medicine.

Fentanyl may cause some people to become drowsy, confused, or dizzy. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are dizzy or not alert. Check with your doctor if you have confusion or drowsiness that is severe enough to interfere with your daily activities.

Using narcotics for a long time can cause severe constipation. To prevent this, your doctor may tell you to take laxatives, drink fluids, or increase the amount of fiber in your diet. Follow the directions carefully. Constipation that continues can lead to more serious problems.

If you have been using this medicine regularly for several weeks or more, do not suddenly stop using it without checking with your doctor. You may be directed to gradually reduce the amount you are using before stopping it completely to lessen the chance of withdrawal side effects.

Using too much fentanyl (the active ingredient contained in Fentanyl Transdermal System) or taking too much of another narcotic with fentanyl, may cause an overdose. If this occurs, get emergency help right away. An overdose can cause severe breathing problems (breathing may even stop), unconsciousness, and death. Serious signs of an overdose include very slow breathing (fewer than 8 breaths each minute) and drowsiness that is so severe you are not able to answer when spoken to, or if asleep, cannot be awakened.

The Actiq® product contains sugar and may increase your chance for tooth decay. Schedule regular dentist visits if you are using Actiq®.

Check with your doctor right away if you have anxiety, restlessness, a fast heartbeat, fever, sweating, muscle spasms, twitching, nausea, vomiting, diarrhea, or see or hear things that are not there. These may be symptoms of a serious condition called serotonin syndrome. Your risk may be higher if you also take certain other medicines that affect serotonin levels in your body.

Using too much of this medicine may cause reduced infertility (unable to have children). Talk with your doctor before using this medicine if you plan to have children.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal (eg, St. John's wort) or vitamin supplements.

Serious side effects

Along with its needed effects, fentanyl may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking fentanyl:

Get emergency help immediately if any of the following symptoms of overdose occur while taking fentanyl:

Symptoms of overdose

• extremely shallow or slow breathing

Other side effects

Some side effects of fentanyl may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

For healthcare professionals

Applies to fentanyl: buccal film, buccal tablet, compounding powder, injectable solution, intravenous solution, nasal spray, oral lozenge, oral transmucosal lozenge, sublingual spray, sublingual tablet, transdermal device, transdermal film extended release.

General adverse events

The most commonly reported adverse reactions included headache, nausea, vomiting, ,dizziness, and constipation.^[Ref]

Nervous system

• Very common (10% or more): Somnolence, dizziness
• Common (1% to 10%): Sedation, pyrexia, fatigue, lethargy, tremor, headache, chills, irritability, malaise, confusion, abnormal thinking, anxiety, dysphoria
• Uncommon (0.1% to 1%): Hyperesthesia
• Very rare (less than 0.01%): Severe hemiplegic migraine
• Frequency not reported: Slurred speech, paresthesia, hypesthesia, tremor
• Postmarketing reports: Loss of consciousness, vertigo, coma, shock, convulsion^[Ref]

Cases of seizures have occasionally been reported, but some investigators have suggested that the seizure-like events reported may have been episodes of fentanyl induced-rigidity.^[Ref]

Cardiovascular

• Common (1% to 10%): Tachycardia
• Uncommon (0.1% to 1%): Sinus tachycardia, chest pain, hypertension, hypotension, palpitations
• Rare (less than 0.1%): Arrhythmias, cardiac arrest
• Frequency not reported: Syncope, vasodilation, bradycardia, bigeminy, myocardial infarct
• Postmarketing reports: Circulatory depression^[Ref]

One report has suggested that epidural fentanyl may mask the pain of myocardial ischemia in patients treated with fentanyl for other reasons. Another report has suggested that QTc interval prolongation may occur in some patients receiving the related narcotic sufentanil. Another report has implicated fentanyl as a potential cause of pulsus alternans in a patient with aortic stenosis and congestive heart failure.

Nevertheless, fentanyl has been advocated by some as a satisfactory agent for coronary artery surgery.^[Ref]

Gastrointestinal

• Very common (10% or more): Nausea (18%), vomiting (10%), constipation
• Common (1% to 10%): Dry mouth, abdominal distension, gastritis, dysphagia, dyspepsia, gastroesophageal reflux disease, ascites, hematemesis, taste perversion, abdominal pain, dehydration, anorexia, cachexia, vomiting, dry mouth, mouth ulcers/stomatitis, tongue edema
• Uncommon (0.1% to 1%): Abdomen enlarged, flatulence
• Rare (less than 0.1%): Choledochoduodenal sphincter spasm
• Frequency not reported: Diarrhea
• Postmarketing reports: Ileus, dental caries, tooth loss, gingival recession, gingivitis, gingival bleeding, lip edema, pharyngeal edema, gum bleeding, ulcer^[Ref]

Genitourinary

• Uncommon (0.1% to 1%): Urinary retention
• Very rare (less than 0.01%): Priapism
• Frequency not reported: Urinary tract infection, urination impaired, hematuria, urinary urgency, dysuria^[Ref]

Dermatologic

• Very common(10% or more): Iontophoretic transdermal system: Application site reaction-Erythema (14%)
• Common (1% to 10%): Application site irritation, pruritus
• Uncommon (0.1% to 1%): Hyperhidrosis, rash
• Rare (less than 0.1%): Systemic rashes
• Frequency not reported: vesicles, papules/pustules, dry and flaky skin, vesiculobullous rash wound site oozing/bleeding, wound site inflammation/erythema
• Postmarketing reports: Application site discharge, application site bleeding, application site infection, rash and scab, erosion, hyperesthesia, application site necrosis^[Ref]

Approximately 60% of patients had some redness at the skin site 24-hours after removal of the iontophoretic transdermal system. The majority of skin events were categorized as mild, erythema and papules were observed; 2 patients had hyperpigmentation at the application site lasting 2 to 3 weeks; 3 patients had a rectangular mark at the application site which persisted for up to 3 months.^[Ref]

Hypersensitivity

• Rare (less than 0.1%): Anaphylaxis^[Ref]

Hematologic

• Common (1% to 10%): Anemia, neutropenia, lymphadenopathy, thrombocytopenia, leukopenia, aspartate aminotransferase increased, blood alkaline phosphatase increased, blood glucose increased, blood lactate increased, hypoalbuminemia, vasodilation^[Ref]

The hemolysis observed may have been related to rapid injection of large volumes of hypotonic fentanyl (the active ingredient contained in Fentanyl Transdermal System) solution. The authors therefore recommend slower injection rates and/or mixture in isotonic fluid.^[Ref]

Immunologic

• Uncommon (0.1% to 1%): Oral candidiasis, cellulitis, pneumonia, urinary tract infection, oral herpes, gastroenteritis, laryngitis
• Very rare (less than 0.01%): Recurrent herpes simplex infection following epidural administration^[Ref]

Metabolic

• Common (1% to 10%): Asthenia, peripheral edema, weight decreased, hypokalemia, hyponatremia, hypocalcemia
• Very rare (less than 0.01%): Syndrome of inappropriate antidiuretic hormone
• Frequency not reported: abnormal healing, dehydration^[Ref]

Endocrine

• Uncommon (0.1% to 1%): Hot flush^[Ref]

Musculoskeletal

• Common (1% to 10%): Fall/accidental injury, back pain, arthralgia, joint swelling, muscular weakness, myoclonus, involuntary muscle contractions, muscle rigidity (involving the respiratory musculature including the glottis)
• Frequency not reported: Leg cramps, myalgia
• Postmarketing reports: Abnormal gait/incoordination^[Ref]

Ocular

• Uncommon (0.1% to 1%): Vision blurred, dry eye
• Rare (less than 0.1%): Abnormal vision^[Ref]

Psychiatric

• Common (1% to 10%): Depression, confusional state, hallucination, insomnia
• Uncommon (0.1% to 1%): Anxiety, agitation, restlessness, agitation, disorientation, abnormal dreams, depersonalization, depression, emotional lability, euphoria, delirium
• Frequency not reported: Nervousness^[Ref]

Respiratory

• Common (1% to 10%): Dyspnea, rhinitis, yawning, respiratory distress, apnea, bradypnea, hypoventilation, respiratory depression
• Uncommon (0.1% to 1%): Cough, increased bronchial secretion, dysphonia, pharyngolaryngeal pain, wheezing, hypoxia, exertional dyspnea
• Very rare (less than 0.01%): Acute noncardiogenic pulmonary edema
• Frequency not reported: Asthma, hiccup, atelectasis, hyperventilation
• Postmarketing reports: Respiratory arrest^[Ref]

See also:

Frequently asked questions

• How long does Fentanyl stay in your system?
• Why is fentanyl so dangerous?
• Fentanyl test strips: where to get & how to use?
• Which drugs cause opioid-induced constipation?
• Carfentanil vs Fentanyl: Which is more dangerous?
• Which painkiller should you use?

Further information

Fentanyl Transdermal System side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer