From the Guidelines
Modafinil is associated with several common side effects, including headache, nausea, nervousness, anxiety, insomnia, and decreased appetite, as reported in a significant proportion of patients in studies such as 1 and 1. The most frequently reported adverse events with modafinil use are headache, nausea, nervousness, rhinitis, diarrhea, back pain, anxiety, insomnia, dizziness, and dyspepsia, occurring in approximately 35% of patients, as noted in 1. More serious but less common side effects of modafinil include rash, psychiatric symptoms like hallucinations or mania, cardiovascular effects such as chest pain, palpitations, and hypertension, and allergic reactions, as mentioned in 1. It is also important to consider that modafinil may reduce the effectiveness of hormonal contraceptives, requiring alternative birth control methods, as stated in 1. The medication works by affecting neurotransmitters like dopamine, histamine, and norepinephrine in the brain, which explains many of its side effects, and patients should be aware of these potential interactions. Some key points to consider when prescribing modafinil include:
- Starting at lower doses (typically 200mg daily taken in the morning) to minimize adverse effects
- Avoiding taking it late in the day to prevent sleep disruption
- Using caution in patients with liver or kidney disease, heart conditions, or psychiatric disorders
- Avoiding combination with alcohol or certain medications that affect the central nervous system
- Consulting a healthcare provider about potential drug interactions before starting modafinil, as recommended in 1.
From the FDA Drug Label
What are possible side effects of modafinil tablets? Modafinil tablets may cause serious side effects. Stop taking modafinil tablets and call your doctor right away or get emergency help if you get any of the following: a serious rash or serious allergic reaction. (See “What is the most important information I should know about modafinil tablets? ”) mental (psychiatric) symptoms, including: depression feeling anxious hearing, seeing, feeling, or sensing things that are not really there (hallucinations) an extreme increase in activity and talking (mania) thoughts of suicide aggressive behavior other mental problems symptoms of a heart problem, including chest pain, abnormal heartbeat, and trouble breathing Common side effects that can happen in anyone who takes modafinil tablets include: headache back pain nausea feeling nervous stuffy nose diarrhea feeling anxious trouble sleeping dizziness upset stomach
The possible side effects of modafinil tablets include:
- Serious side effects:
- Serious rash or serious allergic reaction
- Mental (psychiatric) symptoms, including:
- Depression
- Feeling anxious
- Hallucinations
- Mania
- Thoughts of suicide
- Aggressive behavior
- Other mental problems
- Symptoms of a heart problem, including:
- Chest pain
- Abnormal heartbeat
- Trouble breathing
- Common side effects:
- Headache
- Back pain
- Nausea
- Feeling nervous
- Stuffy nose
- Diarrhea
- Feeling anxious
- Trouble sleeping
- Dizziness
- Upset stomach 2
From the Research
Side Effects of Modafinil
- The most common side effects of modafinil include headache, nausea, and nervousness 3
- In a study of 283 patients, modafinil was found to be well tolerated, with only headache reported with significantly greater frequency compared to placebo 3
- Other potential side effects of modafinil include dizziness, fatigue, and insomnia 4
- Modafinil may also reduce the efficacy of low-dose oral contraceptives via enzymatic induction 3
- In rare cases, modafinil may cause more serious side effects, such as allergic reactions or increased heart rate and blood pressure 5
Comparison to Other Stimulants
- Modafinil has been found to have a lower abuse potential compared to other psychostimulants, such as dexamphetamine and methylphenidate 3, 5
- Modafinil has also been found to have a lower risk of withdrawal symptoms compared to other stimulants 3, 6
- In a study comparing modafinil to sodium oxybate, modafinil was found to have a similar effect on excessive daytime sleepiness, but with less common nausea 7
Special Considerations
- Modafinil is contraindicated in patients with moderate to severe hypertension 3
- Patients with hepatic or renal impairment may require dose adjustments due to changes in modafinil's pharmacokinetics 3
- Modafinil may interact with other medications, such as venlafaxine hydrochloride, which can be used to control cataplectic attacks 6