7 Modafinil Side Effects You Should Know About

Modafinil (Provigil) is a prescription-only medication that helps certain people with conditions that cause extreme sleepiness stay awake. For people living with narcolepsy, modafinil is a first-choice medication. It’s also FDA approved to help with extreme sleepiness from obstructive sleep apnea or shift work disorder.

If you’ve been prescribed modafinil, it’s a good idea to know about its risks and side effects.

Modafinil side effects at a glance 

Some modafinil side effects are more common than others. Common side effects of the medication include:

• Headache

• Nausea

• Nervousness

• Runny nose

• Back pain

• Diarrhea

• Anxiety

• Dizziness

• Upset stomach

• Trouble sleeping

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Modafinil also has some more serious side effects to be aware of. These are rare, but they can occur. Examples include:

• Serious mental health symptoms, like hallucinations, delusions, and aggression

• Severe skin reactions

• Heart problems

• Dependence and misuse

Below, we’ll discuss seven notable modafinil side effects to know about.

1. Headache

Headaches are the most common modafinil side effect. In fact, over 30% of people taking modafinil in clinical trials experienced headaches.

Headaches are more common with higher dosages of modafinil (300 mg to 400 mg per day). So a lower dosage (200 mg per day) may be less likely to cause headaches. If you do need a higher dosage, increasing your dosage slowly may help you avoid headaches. Talk to your healthcare provider about how to accomplish this.

If you do experience headaches while taking modafinil, some lifestyle changes may help. Examples include:

• Staying hydrated by drinking plenty of fluids

• Exercising as part of your daily routine

• Trying stress-relieving practices like meditation and breathing exercises

• Avoiding certain foods and beverages that can worsen headaches, including those that contain nitrites, alcohol, and aspartame

You can also ask your healthcare provider or pharmacist about taking an over-the-counter (OTC) pain reliever, like ibuprofen (Advil, Motrin) or acetaminophen (Tylenol). These can be helpful for occasional headaches. 

If your headaches don’t seem to get better or they feel severe, talk to your provider. They may want to determine if there’s something else causing your headaches.

2. Nausea

Nausea is another common modafinil side effect. If you find yourself nauseated after taking modafinil, here are some tips that may help:

• Drink water consistently.

• Eat smaller, more frequent meals.

• Avoid spicy, fatty, or fried foods.

• Consume ginger or peppermint products, like teas.

If these lifestyle changes don’t work, talk to your healthcare provider or pharmacist about whether OTC nausea medications may help. One example is bismuth subsalicylate (Pepto-Bismol). There’s also prescription-only nausea medications that your provider may recommend. 

Keep in mind that nausea from modafinil should get better, or stop completely, as your body adjusts to the medication. If your nausea doesn’t stop or is affecting your daily life, contact your provider about what to do next.

3. Mood changes

Modafinil is a stimulant medication. Stimulants can affect your mood and increase feelings of nervousness and anxiety. However, anxiety may be less likely with lower dosages of modafinil. If you experience feelings of nervousness or anxiety while taking modafinil, let your healthcare provider know.

More seriously, modafinil can cause severe mental health symptoms like hallucinations, aggression, and mania. It may also cause suicidal thoughts. These extreme mood changes are more likely if you have an existing mental health condition. 

If you have a history of one of these conditions — including psychosis (a break from reality) or depression — let your provider know. They may want to monitor you more closely when you’re starting treatment modafinil. If you develop any mental health changes, you may need to stop taking modafinil.

If you or someone you know is having thoughts of suicide, you’re not alone, and help is available. Call the National Suicide Prevention Lifeline at 988, or text HOME to 741-741 to reach the Crisis Text Line.

4. Trouble sleeping

Stimulants like modafinil can also cause trouble sleeping (insomnia). Even though modafinil is used to help prevent excessive sleepiness, you’ll still want to be able to sleep when you need to while you’re taking it.

Modafinil is usually taken in the morning to prevent trouble sleeping at night. But if you’re taking it for shift work disorder, you’ll want to take it 1 hour before your shift starts.

If modafinil causes you to have trouble sleeping at night — or at another time if you work at night — there are a few ways to manage your insomnia:

• Make sure you have good sleep hygiene habits, like limiting bright lights before bedtime and having a consistent bedtime routine.

• Avoid energy drinks and beverages with alcohol and caffeine before bedtime.

• Practice meditation or deep breathing before you go to sleep.

If improving your sleep hygiene doesn’t work, consider talking to your provider about trying cognitive behavioral therapy (CBT) for sleep. They may also recommend lowering your modafinil dosage or stopping treatment with the medication entirely.

5. Serious skin and allergic reactions

Modafinil has the potential to cause serious skin and allergic reactions. Although rare, some of these skin reactions may be dangerous and require hospitalization. Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and drug rash with eosinophilia and systemic symptoms (DRESS) are skin reactions that have been reported in people taking modafinil.

Most serious rashes develop within 1 to 5 weeks after starting treatment with modafinil. But they may appear later on as well. Often, serious rashes will develop along with other symptoms like fever or vomiting.

Even though non-severe rashes can happen with modafinil, it’s hard to tell whether a rash will turn out to be severe. So modafinil is usually stopped at the first sign of a rash. Contact your healthcare provider right away if you develop a rash while taking modafinil.

6. Heart problems

Modafinil has the potential to cause heart problems. Possible heart-related side effects include chest pain, faster than normal heartbeat, and shortness of breath. If you have existing heart problems or have had a recent heart attack, your healthcare provider may monitor you more closely for these side effects.

If you experience any heart-related symptoms while taking modafinil, contact your provider right away. They may want to perform some tests to check on your heart.

Good to know: It’s not common, but it’s possible that stimulants like modafinil can increase your blood pressure. Your provider may monitor you more closely and ask you to check your blood pressure at home if you already have high blood pressure.

7. Dependence and misuse

Modafinil is a controlled substance. This means it has the potential to cause dependence and misuse. There’s also restrictions around how it can be prescribed and refilled.

Modafinil may cause feelings of euphoria (a “high”). It may also cause a change in mood, perceptions, or feelings. This is because modafinil affects a few different brain chemicals, including dopamine. Dopamine is a chemical in the body that helps manage feelings of pleasure and motivation. Substances that increase the amount of dopamine in the brain often have the potential to cause dependence and misuse.

Taking modafinil exactly as prescribed can help lower your risk of dependence and misuse. If you have a history of substance use disorder, let your healthcare provider know. Modafinil may not be the best option for you in this case.

If you or someone you know struggles with substance use, help is available. Call SAMHSA’s National Helpline at 1-800-662-4357 to learn about resources in your area.

When should you contact your healthcare provider about modafinil side effects?

Most common modafinil side effects are mild and can be managed at home. But never hesitate to contact your healthcare provider or pharmacist if you’re having side effects that are bothersome.

If you experience any severe side effects — such as a rash, mood changes, or a fast heartbeat — contact your provider right away. You may need to stop taking modafinil. Or they may recommend that you seek further care.

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Written by:

Nicole E. Cieri-Hutcherson, PharmD, BCPS, NCMP

Nicole E. Cieri-Hutcherson, PharmD, BCPS, NCMP, has over a decade of experience as a pharmacist, professor, and researcher. She was a full-time clinical professor in the pharmacy practice department at D’Youville School of Pharmacy before subsequently joining the faculty of the pharmacy practice department at the University at Buffalo School of Pharmacy and Pharmaceutical Sciences.

Edited by:

Amy B. Gragnolati, PharmD, BCPS

Amy Gragnolati, PharmD, BCPS, is a pharmacy editor for GoodRx. Amy currently holds her pharmacist license in Georgia and California.

Reviewed by:

Christina Aungst, PharmD

Christina Aungst, PharmD, is a pharmacy editor for GoodRx. She began writing for GoodRx Health in 2019, transitioning from freelance writer to editor in 2021.

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