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Modafinil Side Effects

Commonly reported side effects of modafinil include headache and nausea. Other side effects include anorexia and xerostomia. See below for a comprehensive list of adverse effects.

For the Consumer

Applies to modafinil: oral tablet

In addition to its needed effects, some unwanted effects may be caused by modafinil. In the event that any of these side effects do occur, they may require medical attention.

You should check with your doctor immediately if any of these side effects occur when 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

If any of the following symptoms of overdose occur while taking modafinil, get emergency help immediately:

Symptoms of overdose
  • Agitation or excitement
  • fast or pounding heartbeat
  • increased blood pressure
  • trouble with sleeping

Some of the side effects that can occur with modafinil may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

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

For Healthcare Professionals

Applies to modafinil: oral tablet


General side effects including headache (50% vs 40% in placebo), chest pain (2%), neck pain (2%), chills (2%), rigid neck (1%), and fever/chills (1%) have been reported.[Ref]


Some cases of rash were serious or life-threatening requiring hospitalization and discontinuation of treatment. Some cases have occurred after prolonged treatment (e.g., 3 months), while others have been reported within 1 to 5 weeks of initiation of treatment. Although benign rashes may also occur, modafinil should be discontinued at the first sign of rash unless the rash is definitely not drug-related.[Ref]

Dermatologic side effects including rash, Stevens-Johnson Syndrome, toxic epidermal necrolysis, and drug rash with eosinophilia and systemic symptoms have been reported. In addition, herpes simplex (1%) and dry skin (1%) have been reported.[Ref]


Multi-organ hypersensitivity reactions have occurred in close temporal association to the initiation of modafinil, including at least one fatality in postmarketing experience. Multi-organ hypersensitivity reactions may result in hospitalization or be life-threatening. Patients typically present with fever and rash associated with other organ system involvement. Myocarditis, hepatitis, liver function test abnormalities, hematological abnormalities (e.g., eosinophilia, leukopenia, thrombocytopenia), pruritus, and asthenia may also occur. If multi-organ hypersensitivity is suspected at any time, modafinil should be discontinued.

Hypersensitivity reactions including rare cases of angioedema have been observed in patients treated with the racemic mixture of modafinil. Although no such cases were observed in modafinil clinical trials, angioedema has been reported in postmarketing experience. Patients should be advised to immediately discontinue therapy and promptly report any signs or symptoms suggesting angioedema or anaphylaxis to their physician (e.g., swelling of face, eyes, lips, tongue or larynx; difficulty in swallowing or breathing; hoarseness).

Multi-organ hypersensitivity reactions have occurred in close temporal association to the initiation of modafinil, including at least one fatality in postmarketing experience.


Psychiatric side effects, some resulting in hospitalization, have been reported. These include mania, delusions, hallucinations, and suicidal ideation. Many, but not all, patients had a prior psychiatric history. Caution should be exercised when modafinil is given to patients with a history of psychosis, depression, or mania. Clinicians should consider discontinuation if psychiatric symptoms develop in association with modafinil therapy. Postmarketing adverse events associated with the use of modafinil have included aggression.[Ref]


Cardiovascular side effects including hypotension (2%), hypertension (2%), vasodilation (1%), arrhythmia (1%), and syncope (1%) have been reported. One case of modafinil-induced premature ventricular contractions ((PVCs), ventricular ectopic beats) has been reported and confirmed by rechallenge. Following discontinuation of modafinil, PVCs continued for 14 to 20 days before finally subsiding.[Ref]


Gastrointestinal side effects including nausea (13%), diarrhea (8%), dry mouth (5%), anorexia (5%), abnormal liver function (3% vs 2% placebo), vomiting (2%), mouth ulcer (1%), gingivitis (1%), thirst (1%), and hypersalivation have been reported.[Ref]


Respiratory side effects including rhinitis (11% vs 8% placebo), pharyngitis (6%), lung disorder (4%), dyspnea (2%), asthma (1%), and epistaxis (1%) have been reported.[Ref]

Nervous system

Nervous system side effects including nervousness (8% vs 6% placebo), dizziness (5% vs 4% placebo), depression (4% vs 3% placebo), anxiety (4%), cataplexy (3% vs 2% placebo), insomnia (3%), paresthesia (3%), dyskinesia (2%), hypertonia (2%), confusion (1%), amnesia (1%), emotional lability (1%), ataxia (1%), and tremor (1%) have been reported.[Ref]


Hematologic side effects including eosinophilia (2%) have been reported.[Ref]


Ocular side effects including amblyopia (2%), and abnormal vision (2%) have been reported.[Ref]


Metabolic side effects including hyperglycemia (1%) and albuminuria (1%) have been reported.[Ref]


Musculoskeletal side effects including joint disorder (1%) have been reported.[Ref]


Genitourinary side effects including abnormal urine (1%), urinary retention (1%), and abnormal ejaculation (1%) have been reported.[Ref]


1. "Product Information. Provigil (modafinil)." Cephalon, Inc, West Chester, PA.

2. Vorspan F, Warot D, Consoli A, Cohen D, Mazet P "Mania in a boy treated with modafinil for narcolepsy." Am J Psychiatry 162 (2005): 813-4

3. Narendran R, Young CM, Valenti AM, Nickolova MK, Pristach CA "Is psychosis exacerbated by modafinil?" Arch Gen Psychiatry 59 (2002): 292-3

4. Oskooilar N "A case of premature ventricular contractions with modafinil." Am J Psychiatry 162 (2005): 1983-4

5. Heitmann J, Cassel W, Grote L, et al. "Does short-term treatment with modafinil affect blood pressure in patients with obstructive sleep apnea?" Clin Pharmacol Ther 65 (1999): 328-35

6. "Multum Information Services, Inc. Expert Review Panel"

Not all side effects for modafinil may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

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