Modafinil Side Effects

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

Applies to modafinil: oral tablet.

Precautions

Your doctor should check your progress at regular visits to make sure that this medicine is working properly. Your blood pressure may need to be checked more often while taking this medicine.

It is important to tell your doctor if you become pregnant. Your doctor may want you to join a pregnancy registry for patients taking this medicine.

Serious skin reactions can occur with this medicine. Stop using this medicine and check with your doctor right away if you have blistering, peeling, or loosening of the skin; red skin lesions; severe acne or skin rash; sores or ulcers on the skin; or fever or chills while you are using this medicine.

This medicine may cause you to have a serious type of allergic reaction called anaphylaxis. Anaphylaxis can be life-threatening and requires immediate medical attention. Stop taking modafinil and call your doctor right away if you have a skin rash; itching; hives; hoarseness; trouble breathing; trouble swallowing; or any swelling of your hands, face, or mouth while you are using this medicine.

This medicine may cause serious allergic reactions affecting multiple body organs (e.g., heart, liver, or blood cells). Stop using this medicine and check with your doctor right away if you have the following symptoms: chest pain or discomfort, fever and chills, dark urine, headache, rash, stomach pain, unusual tiredness, unusual bleeding or bruising, or yellow eyes or skin.

If you think modafinil is not working properly after you have taken it for a few weeks, do not increase the dose. Instead, check with your doctor.

If you are using a medicine for birth control (such as birth control pills, implants, shots, patches, vaginal rings, or an IUD), it may not work properly while you are taking modafinil. To keep from getting pregnant, use another form of birth control while you are using this medicine and for one month after your last dose. Other forms of birth control include condoms, diaphragms, or contraceptive foams or jellies.

Modafinil may cause some people to feel dizzy, drowsy, have trouble thinking or controlling movements, or trouble seeing clearly. Make sure you know how you react to this medicine before you drive, use machines, or do other jobs that require you to be alert, well-coordinated, or able to think or see well.

Stop using this medicine and check with your doctor right away if you have the following symptoms while taking the medicine: aggressive behavior, anxiety, depression, hallucinations, mania, thoughts of suicide, or other mental problems.

If you have been taking this medicine for a long time or in large doses and you think you may have become mentally or physically dependent on it, check with your doctor. Some signs of dependence on modafinil are:

• a strong desire or need to continue taking the medicine.
• a need to increase the dose to receive the effects of the medicine.
• withdrawal side effects when you stop taking the medicine.

While you are taking this medicine, be careful to limit the amount of alcohol that you drink.

If you have been taking this medicine in large doses or for a long time, do not stop taking it without first checking with your doctor. Your doctor may want you to gradually reduce the amount you are taking before stopping it completely.

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 or vitamin supplements.

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:

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:

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 adverse events

The most common adverse reactions occurring in 5% of patients or greater included headache, nausea, nervousness, rhinitis, diarrhea, back pain, anxiety, insomnia, dizziness, and dyspepsia.^[Ref]

Cardiovascular

• Common (1% to 10%): Hypertension, palpitation, tachycardia, vasodilation
• Uncommon (0.1% to 1%): Extrasystoles, arrhythmia, bradycardia, hypotension, abnormal ECG
• Frequency not reported: Hypotension
• Postmarketing reports: Ischemic heart disease

Dermatologic

• Uncommon (0.1% to 1%): Rash, acne, pruritus
• Postmarketing reports: Serious or life threatening rash, including erythema multiforme, Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and drug rash with eosinophilia and system symptoms (DRESS), hyperhidrosis, urticaria (hives), angioedema, eczema

Endocrine

• Uncommon (0.1% to 1%): Diabetes mellitus

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

Genitourinary

• Common (1% to 10%): Urine abnormality, hematuria, pyuria
• Uncommon (0.1% to 1%): Urinary frequency
• Frequency not reported: Urinary tract infection
• Postmarketing reports: Foul urine odor

Hematologic

• Common (1% to 10%): Eosinophilia
• Uncommon (0.1% to 1%): Leukopenia
• Frequency not reported: Ecchymosis
• Postmarketing reports: Agranulocytosis

Hepatic

• Common (1% to 10%): Abnormal liver function
• Frequency not reported: Elevated liver enzymes

Hypersensitivity

• Frequency not reported: Allergic reaction
• Postmarketing reports: Multi-organ system hypersensitivity reactions, anaphylaxis

Metabolic

• Uncommon (0.1% to 1%): Hypercholesterolemia, hyperglycemia
• Frequency not reported: Increased gamma glutamyltransferase, increased alkaline phosphatase

Musculoskeletal

• Common (1% to 10%): Back pain, hypertonia, neck rigidity
• Uncommon (0.1% to 1%): Myasthenia, twitch, neck pain, myalgia, leg cramps, arthralgia
• Frequency not reported: Arthritis
• Postmarketing reports: Muscle weakness

Nervous system

• Very common (10% or more): Headache (up to 34%)
• Common (1% to 10%): Dizziness, paresthesia, somnolence, confusion, dyskinesia, hyperkinesia, tremor, vertigo, taste perversion
• Uncommon (0.1% to 1%): Incoordination, movement disorder, speech disorder
• Frequency not reported: Migraine, cataplexy, pro-facial dyskinesias
• Postmarketing reports: Dyskinesias including tardive dyskinesia, convulsions

Ocular

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

Other

• Common (1% to 10%): Anorexia, chest pain, fever, viral infection, thirst, edema, chills, flu syndrome, herpes simplex, infection, pain
• Frequency not reported: Hypothermia, increased appetite, weight loss, weight gain, ear pain, dysmenorrhea
• Postmarketing reports: Tolerance, lack of efficacy, aggravated condition, malaise, fatigue

Psychiatric

• Common (1% to 10%): Nervousness, anxiety, insomnia, depression, agitation, emotional lability
• Uncommon (0.1% to 1%): Sleep disorder, decreased libido, hostility, depersonalization, personality disorder, abnormal dreams, aggression, suicidal ideation, psychomotor hyperactivity
• Rare (0.01% to 0.1%): Hallucinations, mania, psychosis
• Frequency not reported: Asthenia
• Postmarketing reports: Irritability, confusion, suicide attempt, aggravated depression, delusions, thinking abnormally

Respiratory

• Common (1% to 10%): Rhinitis, pharyngitis, asthma, epistaxis, lung disorder
• Uncommon (0.1% to 1%): Dyspnea, increased cough
• Frequency not reported: Sinusitis, bronchitis

See also:

Frequently asked questions

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

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.

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