Modafinil Side Effects

Medically reviewed by Drugs.com. Last updated on Jun 19, 2023.

Applies to modafinil: oral tablet.

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

Other 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

For Healthcare Professionals

Applies to modafinil: oral tablet.

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]

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]

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]

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?
• Modafinil vs Adderall: What's the difference?

Further information

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