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Modafinil (wakefulness-promoting agent)

Written by Stephanie Nera, RPh, PharmD · Pharmacology

Updated Jun 16, 2021

Modafinil is a drug that keeps you awake. The exact mechanism of action is unclear, but studies show that it increases dopamine in the brain and decreases GABA-mediated neurotransmission.modafinil

Know the basics

What is modafinil used for?

It reduces extreme sleepiness due to narcolepsy and other sleep disorders, such as periods of stopped breathing during sleep (obstructive sleep apnea). It is also effective in treating shift work sleep disorder.

How should I take modafinil?

Read the directions on the packaging for complete information. Check the label and expiration date.

As an oral tablet, you should swallow it whole with a glass of water. Do not chew, crush, or dissolve the tablet in liquid.

How do I store modafinil?

This product is best stored at room temperature away from direct light and moisture. To prevent drug damage, you should not store it in the bathroom or the freezer. 

There may be different brands of this drug that may have different storage needs. So, it is important to always check the product package for instructions on storage, or ask your pharmacist. For safety, you should keep all medicines away from children and pets.

You should not flush this product down the toilet or pour them into a drain unless instructed to do so. Additionally, it is important to properly discard this product when it is expired or no longer needed. Consult your pharmacist for more details about how to safely discard your product.

Know the precautions & warnings

What should I know before using modafinil?

Before using this drug, tell your doctor if you are/have:

  • Pregnant or breastfeeding.
  • Taking any other medicines. This includes any prescription, OTC, and herbal remedies.
  • An allergy to any of the ingredients of this product.
  • Any other illnesses, disorders, or medical conditions.

Is it safe to take modafinil during pregnancy or breastfeeding?

Unfortunately, there isn’t enough information about the safety of using this drug during pregnancy and breastfeeding. Please always consult with your doctor to weigh the potential benefits and risks before taking any medication.

This medication is pregnancy risk category C according to the US Food and Drug Administration (FDA).

FDA pregnancy risk category reference below:

  • A=No risk
  • B=No risk in some studies
  • C=There may be some risk
  • D=Positive evidence of risk
  • X=Contraindicated
  • N=Unknown

Know the side effects

What are the side effects of modafinil?

Like all drugs, this product may have side effects. If they occur, side effects are generally mild and resolve once treatment is finished or the dose is lowered. Some reported side effects include:

  • Headache
  • Dizziness
  • Irritability, anxiety
  • Nausea
  • Diarrhea
  • Trouble sleeping (insomnia)
  • Dry mouth (xerostomia)

However, not everyone experiences these side effects. In addition, some people may experience other side effects. So, if you have any concerns about a side effect, please consult your doctor or pharmacist.

Know the interactions

What drugs may interact with modafinil?

This medication may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects. 

To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, nonprescription drugs, and herbal products) and share it with your doctor and pharmacist. 

Drugs with known interactions:

  • Cyclosporine
  • Propranolol
  • Rifampin
  • Benzodiazepines
  • Azole-type antifungals
  • Carbamazepine
  • Phenytoin
  • Phenobarbital
  • Amitriptyline, doxepin, imipramine, nortriptyline
  • MAOIs
  • Oral contraceptive pills

If you experience an adverse drug interaction, stop taking this drug and continue taking your other medication. Inform your doctor immediately to reevaluate your treatment plan. Approaches include dose adjustment, drug substitution, or ending therapy.

Does food or alcohol interact with modafinil?

This drug may interact with food or alcohol by altering the way the drug works or increase the risk for serious side effects. Do not take this drug with alcohol, as it cause drowsiness. Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.

What health conditions may interact with modafinil?

This drug may interact with underlying conditions. This interaction may worsen your health condition or alter the way the drug works. Therefore, it is important to always let your doctor and pharmacist know all the health conditions you currently have, especially:

  • History of alcoholism
  • History of drug abuse or addiction
  • Angina
  • History of heart attack
  • Heart disease
  • Depression
  • Hypertension
  • Psychoses
  • Liver disease

Understand the dosage

The information provided is not a substitute for any medical advice. Therefore, you should always consult with your doctor or pharmacist before using any medication.

What is the dose for an adult?


Take 200 mg once a day in the morning.

Obstructive Sleep Apnea/Hypopnea Syndrome

Take 200 mg once a day in the morning.

Shift Work Sleep Disorder

Take 200 mg once a day in the morning.

What is the dose for a child?

Attention deficit hyperactivity disorder  (ADHD)

Children ≥6 years and Adolescents ≤13 years:

<30 kg body weight: give 200 to 340 mg once a day.

>30 kg body weight: give 300 to 425 mg once a day.

How is modafinil available?

Modafinil is available in the following dosage forms and strengths:

  • Oral tablet 100 mg, 200 mg.

What should I do in case of an emergency or overdose?

In case of an emergency or an overdose, induce emesis (vomiting) and/or perform gastric lavage. Immediately contact your local emergency services or go to the nearest emergency room.

What should I do if I miss a dose?

If you miss a dose, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.


Hello Health Group does not provide medical advice, diagnosis or treatment.

Written by

Stephanie Nera, RPh, PharmD


Updated Jun 16, 2021

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