Summary

Commonly reported side effects of fentanyl include: fever, respiratory depression, nausea, vomiting, and diaphoresis. Other side effects include: hypoventilation. Continue reading for a comprehensive list of adverse effects.

Applies to fentanyl: lozenge/troche, spray, tablet. Other dosage forms:

• injection solution
• nasal spray
• transdermal patch extended release

Serious side effects of Fentanyl

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:

More common

• Black, tarry stools
• blurred vision
• chest pain
• confusion
• convulsions
• cough
• decreased urine
• difficult or labored breathing
• dizziness
• dry mouth
• fainting
• fever or chills
• increased thirst
• irregular heartbeat
• lightheadedness
• loss of appetite
• lower back or side pain
• mood changes
• muscle pain or cramps
• nausea or vomiting
• nervousness
• numbness or tingling in the hands, feet, or lips
• painful or difficult urination
• pale skin
• pounding in the ears
• rapid breathing
• sneezing
• sore throat
• sunken eyes
• swelling of the hands, ankles, feet, or lower legs
• tightness in the chest
• troubled breathing with exertion
• ulcers, sores, or white spots in the mouth
• unusual bleeding or bruising
• unusual tiredness or weakness
• wrinkled skin

Less common

• Abdominal or stomach pain
• change in walking and balance
• clumsiness or unsteadiness
• decreased awareness or responsiveness
• decreased frequency of urination
• headache
• muscle twitching or jerking
• pounding in the ears
• rhythmic movement of the muscles
• seeing, hearing, or feeling things that are not there
• seizures
• severe constipation
• severe sleepiness
• shakiness in the legs, arms, hands, or feet
• slow or fast heartbeat
• thinking abnormalities
• trembling or shaking of the hands or feet

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 of Fentanyl

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:

More common

• Back pain
• diarrhea
• difficulty having a bowel movement (stool)
• difficulty with moving
• discouragement
• feeling sad or empty
• irritability
• lack or loss of strength
• loss of interest or pleasure
• muscle stiffness
• pain in the joints
• sleepiness or unusual drowsiness
• tiredness
• trouble concentrating
• trouble sleeping
• weight loss

Less common

• Changes in vision
• excessive muscle tone
• feeling of constant movement of self or surroundings
• feeling of warmth or heat
• flushing or redness of the skin, especially on the face and neck
• irritation, pain, or sores at the site of application
• itching skin
• muscle tension or tightness
• rash
• sensation of spinning
• sweating

Incidence not known

• Tooth pain
• trouble with gums
• trouble with teeth

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

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

The hemolysis observed may have been related to rapid injection of large volumes of hypotonic fentanyl solution. The authors therefore recommend slower injection rates and/or mixture in isotonic fluid.^[Ref]

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]

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]