From the Guidelines
Modafinil is well tolerated, with a good safety profile, and the most frequent adverse events are headache, nausea, nervousness, rhinitis, diarrhea, back pain, anxiety, insomnia, dizziness, and dyspepsia, occurring in approximately 35% of patients 1. The side effects of modafinil can be categorized into common and less common adverse events. Common side effects include:
- Headache
- Nausea
- Nervousness
- Rhinitis
- Diarrhea
- Back pain
- Anxiety
- Insomnia
- Dizziness
- Dyspepsia These side effects are generally mild to moderate in severity and occur in approximately 35% of patients taking modafinil 1. It is essential to note that modafinil has a novel mechanism of action and less abuse potential compared to other psychostimulants 1. The half-life of modafinil is approximately 15 hours, and a steady state is reached after 2 to 4 days of dosing 1. Higher doses (200–400 mg/d) of modafinil may be more effective for sleepiness; however, lower doses (50–200 mg/d) seem to be better for concentration problems and fatigue 1. Patients should be aware of the potential side effects and start at lower doses to minimize adverse events, and immediately report any unusual symptoms to their healthcare provider 1.
From the FDA Drug Label
Modafinil tablets may cause serious side effects including a serious rash or a serious allergic reaction that may affect parts of your body such as your liver or blood cells. Stop taking modafinil tablets and call your doctor right away or get emergency help if you have any of these symptoms: skin rash, hives, sores in your mouth, or your skin blisters and peels swelling of your face, eyes, lips, tongue, or throat trouble swallowing or breathing fever, shortness of breath, swelling of the legs, yellowing of the skin or whites of the eyes, or dark urine
The side effects of Modafinil (Provigil) include:
- Serious rash or serious allergic reaction
- Skin rash, hives, sores in the mouth, or skin blisters and peels
- Swelling of the face, eyes, lips, tongue, or throat
- Trouble swallowing or breathing
- Fever, shortness of breath, swelling of the legs, yellowing of the skin or whites of the eyes, or dark urine 2
From the Research
Common Side Effects of Modafinil
- Headache 3, 4, 5, 6, 7
- Insomnia 3, 4, 5, 6
- Nausea 3, 4
- Nervousness 3
- Hypertension 3, 4, 5
- Decreased appetite 3, 6
- Weight loss 3, 6
- Gastrointestinal discomfort 6
- Dry mouth 5, 7
- Anxiety 5
- Diarrhea 5
- Raise in blood pressure and heart rate 5
Serious Side Effects of Modafinil
- Severe dermatological effects in children, including maculopapular and morbilliform rash, erythema multiforme and Stevens-Johnson Syndrome 3, 5, 6
- Skin rash, including one case of possible erythema multiforme/Stevens Johnson Syndrome 6
Special Considerations
- Modafinil may have some abuse/addictive potential although no cases have been reported to date 3
- Intoxication and dependence associated to modafinil are uncommon 5
- Modafinil induces and inhibits several cytochrome P450 isoenzymes and has the potential for interacting with drugs from all classes 3
- The modafinil dose should be reduced in the elderly and in patients with hepatic disease 3
- Caution is needed in patients with severe renal insufficiency because of substantial increases in levels of modafinil acid 3