Modafinil Side Effects

Medically reviewed by Drugs.com. Last updated on Feb 28, 2024.

Applies to modafinil: oral tablet.

Common side effects of modafinil

Some side effects of modafinil 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

• anxiety
• headache
• nausea
• nervousness

Less common

• back pain
• belching
• decrease in appetite
• diarrhea
• difficulty having a bowel movement
• dryness of the mouth
• dryness of the skin
• feeling of constant movement of self or surroundings
• flushing or redness of the skin
• heartburn
• indigestion
• muscle stiffness
• sores, ulcers, or white spots on the lips or in the mouth
• sour stomach
• stomach discomfort upset or pain
• stuffy or runny nose
• swelling
• tingling, burning, or prickling sensations in the skin
• vomiting

Serious side effects of modafinil

Along with its needed effects, modafinil 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 modafinil:

Less common

• black, tarry stools
• blurred vision or other vision changes
• chest pain
• chills or fever
• clumsiness or unsteadiness
• confusion
• dizziness or fainting
• increased thirst and urination
• mental depression
• problems with memory
• rapidly changing moods
• shortness of breath
• sore throat
• trembling or shaking
• trouble in urinating
• uncontrolled movements of the face, mouth, or tongue
• unusual bleeding or bruising
• unusual tiredness or weakness

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

Symptoms of overdose

• agitation or excitement
• fast or pounding heartbeat
• increased blood pressure
• trouble with sleeping

For healthcare professionals

Applies to modafinil: oral tablet.

General

The development of adverse reactions (skin and hypersensitivity, central nervous system [CNS], psychiatric, and cardiovascular) appear to be related to higher doses; cardiovascular and CNS reactions increase significantly after a total daily dose of more than 400 mg.^[Ref]

Gastrointestinal

• Very common (10% or more): Nausea (up to 11%)
• Common (1% to 10%): Diarrhea, dry mouth, dyspepsia, constipation, flatulence, mouth ulceration, abdominal pain
• Uncommon (0.1% to 1%): Reflux, vomiting, dysphagia, glossitis
• Frequency not reported: Periodontal abscess^[Ref]

Nervous system

• Very common (10% or more): Headache (up to 34%)
• Common (1% to 10%): Dizziness, paresthesia, somnolence, tremor, taste perversion, vertigo, oro-facial dyskinesia, hyperkinesia, hypertonia
• Uncommon (0.1% to 1%): Amnesia, migraine, CNS stimulation, incoordination, movement disorder, speech disorder, hypoesthesia
• Very rare (less than 0.01%): Tardive dyskinesia, convulsions
• Frequency not reported: Cataplexy^[Ref]

Cardiovascular

• Common (1% to 10%): Palpitations, chest pain, hypertension, tachycardia, vasodilation
• Uncommon (0.1% to 1%): Extrasystoles, arrhythmia, bradycardia, hypotension, transient ischemic T-wave changes, abnormal ECG
• Rare (less than 0.1%): Increased blood pressure
• Very rare (less than 0.01%): Ischemic heart disease
• Frequency not reported: Asystole^[Ref]

Dermatologic

• Common (1% to 10%): Sweating, herpes simplex
• Uncommon (0.1% to 1%): Rash, acne, pruritus
• Rare (less than 0.1%): Eczema
• Frequency not reported: Ecchymosis, serious skin reactions (including Stevens-Johnson Syndrome, Toxic Epidermal Necrolysis, Drug Rash with Eosinophilia and Systemic Symptoms, erythema multiforme)^[Ref]

Genitourinary

• Common (1% to 10%): Urine abnormality, hematuria, pyuria
• Uncommon (0.1% to 1%): Urinary frequency
• Rare (less than 0.1%): Foul urine odor
• Frequency not reported: Urinary tract infection^[Ref]

Hematologic

• Common (1% to 10%): Eosinophilia
• Uncommon (0.1% to 1%): Leukopenia
• Postmarketing reports: Agranulocytosis^[Ref]

Hepatic

• Common (1% to 10%): Increased gamma-glutamyltransferase, increased alkaline phosphatase, abnormal liver function, elevated liver enzymes, eosinophilia^[Ref]

Hypersensitivity

• Uncommon (0.1% to 1%): Allergic reaction (e.g., hayfever)
• Very rare (less than 0.01%): Multi-organ hypersensitivity reactions, urticaria (hives), angioedema, anaphylaxis^[Ref]

Metabolic

• Common (1% to 10%): Anorexia, thirst, decreased appetite
• Uncommon (0.1% to 1%): Hypercholesterolemia, hyperglycemia, diabetes mellitus, increased appetite, increased weight, decreased weight^[Ref]

Musculoskeletal

• Common (1% to 10%): Back pain, neck rigidity
• Uncommon (0.1% to 1%): Neck pain, myalgia, myasthenia, leg cramps, arthralgia, twitch, arthritis
• Rare (less than 0.1%): Muscle weakness^[Ref]

Ocular

• Common (1% to 10%): Abnormal vision, blurred vision, amblyopia, eye pain
• Uncommon (0.1% to 1%): Dry eye
• Frequency not reported: Conjunctivitis^[Ref]

Other

• Common (1% to 10%): Chills, edema, asthenia, flu syndrome, thirst
• Uncommon (0.1% to 1%): Peripheral edema, menstrual disorder
• Rare (less than 0.1%): Tolerance, aggravated condition, malaise, fatigue
• Frequency not reported: Infection, pain, accidental injury, fever, viral infection, tooth disorder, hypothermia, ear pain^[Ref]

Psychiatric

• Common (1% to 10%): Insomnia, anxiety, depression, agitation, nervousness, confusion, emotional lability, abnormal thinking, irritability
• Uncommon (0.1% to 1%): Sleep disorder, decreased libido, hostility, depersonalization, personality disorder, abnormal dreams, aggression, suicidal ideation, psychomotor hyperactivity
• Rare (less than 0.1%): Hallucinations, mania, psychosis, delusions, suicide attempt^[Ref]

Respiratory

• Common (1% to 10%): Rhinitis, pharyngitis, lung disorder, asthma, epistaxis
• Uncommon (0.1% to 1%): Sinusitis, dyspnea, increased cough
• Frequency not reported: Bronchitis^[Ref]

Frequently asked questions

• Modafinil: Smart Drug For Decision Fatigue Or Workaholic Crutch?
• How long does it take for Provigil (modafinil) to work?
• Modafinil (Provigil) vs Adderall: What's the difference?
• Does Provigil (modafinil) cause weight loss?
• Is Provigil (modafinil) a controlled substance?

Further information

Modafinil 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.

Some side effects may not be reported. You may report them to the FDA.

Medical Disclaimer