In the U.S.—

• Central nervous system (CNS) stimulant

Modafinil (moe-DAF-i-nil) is used to help people who have narcolepsy to stay awake during the day. Modafinil does not cure narcolepsy and will only work as long as you continue to take it.

This medicine is available only with your doctor's prescription, in the following dosage form:

Oral
• Tablets (U.S.)

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For modafinil, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to modafinil or any other central nervous system stimulating medicine, such as methylphenidate (e.g., Ritalin) or dextroamphetamine (e.g., Dexedrine). Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy—Birth-control medicines, such as birth-control pills or implants, may not work properly while you are using modafinil and for 1 month after you stop using modafinil. If you do not use a different type of birth control during this time, such as condoms, you are more likely to become pregnant. If you are using a medicine for birth control, discuss this with your doctor. Modafinil has not been studied in pregnant women. However, studies in animals suggest that modafinil may cause birth defects and fewer successful pregnancies. Before taking this medicine, make sure your doctor knows if you are pregnant or if you may become pregnant.

Breast-feeding—It is not known whether modafinil passes into the breast milk. Although most medicines pass into breast milk in small amounts, many of them may be used safely while breast-feeding. Mothers who are taking modafinil and who wish to breast-feed should discuss this with their doctor.

Children—Studies on this medicine have been done only in adult patients, and there is no specific information comparing use of modafinil in children with use in other age groups.

Older adults—Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults. Although there is no specific information comparing use of modafinil in the elderly with use in other age groups, this medicine has been used in a few elderly patients and was not shown to cause different side effects or problems in older people than it does in younger adults.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking modafinil, it is especially important that your health care professional know if you are taking any of the following:

• Amantadine (e.g., Symmetrel) or
• Amphetamines or
• Appetite suppressants (diet pills) or
• Bupropion (e.g., Wellbutrin, Zyban) or
• Caffeine (e.g., NoDoz) or
• Chlophedianol (e.g., Ulone) or
• Cocaine or
• Medicine for asthma or other breathing problems or
• Medicine for colds, sinus problems, or hay fever or other allergies (including nose drops or sprays) or
• Methylphenidate (e.g., Ritalin) or
• Nabilone (e.g., Cesamet) or
• Pemoline (e.g., Cylert)—These medicines may add to the central nervous system (CNS) stimulating effects of modafinil, such as irritability, nervousness, trembling or shaking, or trouble in sleeping at night

• Cyclosporine (e.g., Sandimmune) or
• Diazepam (e.g., Valium) or
• Mephenytoin (e.g., Mesantoin) or
• Phenytoin (e.g., Dilantin) or
• Propranolol (e.g., Inderal) or
• Theophylline (e.g., Slo-Bid Gyrocaps, Theo-Dur) or
• Warfarin (e.g., Coumadin)—Higher or lower blood levels of these medicines may occur. This increases the chance that unwanted effects will occur or that these medicines will not work properly. Your doctor may need to adjust your dose of these medicines

• Monoamine oxidase (MAO) inhibitor activity (isocarboxazid [e.g., Marplan], phenelzine [e.g., Nardil], procarbazine [e.g., Matulane], selegiline [e.g., Eldepryl], tranylcypromine [e.g., Parnate])—These medicines can cause very serious problems when they are used with certain other medicines. It is not known if they will cause any problems when they are used with modafinil

• Steroid contraceptives (birth control medicines, including birth control pills and implants [e.g., Norplant])—Birth control medicines may not work properly while you are taking modafinil and for 1 month after you stop taking modafinil. It is important that you use another method of birth control to avoid pregnancy during and for 1 month after modafinil therapy. Discuss this with your doctor

• Tricyclic antidepressants (amitriptyline [e.g., Elavil], amoxapine [e.g., Asendin], clomipramine [e.g., Anafranil], desipramine [e.g., Pertofrane], doxepin [e.g., Sinequan], imipramine [e.g., Tofranil], nortriptyline [e.g., Aventyl], protriptyline [e.g., Vivactil], trimipramine [e.g., Surmontil])—Higher blood levels of these medicines may occur, increasing the chance that unwanted effects will occur

• Heart disease or
• Heart attack, recent or
• High blood pressure—It is not known how modafinil will affect these conditions

• Heart problems during the use of other central nervous system (CNS) stimulating medicines, history of—Similar problems may occur when you use modafinil

• Kidney disease, severe—Higher blood levels of a breakdown product of modafinil may occur. It is not known if this will cause any problems

• Liver disease, severe—Higher blood levels of modafinil may occur, increasing the chance of having unwanted effects. You will probably receive a lower dose than a patient without liver disease

• Severe mental illness, history of—Modafinil may cause the illness to return

Take this medicine only as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered. If too much is taken, it may become habit-forming.

Dosing—

The dose of modafinil will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average dose of modafinil. If your dose is different, do not change it unless your doctor tells you to do so.

The number of tablets that you take depends on the strength of the medicine.

• For oral dosage form (tablets):
  • For narcolepsy:
    • Adults—Usually 200 milligrams (mg) a day, taken as a single dose in the morning.
    • Children—Use and dose must be determined by your doctor.

Missed dose—

If you miss a dose of modafinil and you remember it before 12:00 noon the same day, take the missed dose as soon as possible. If you do not remember until later, skip the missed dose so that this medicine will not make it difficult for you to sleep that night. Go back to your regular dosing schedule. Do not double doses.

Storage—

To store this medicine:

• Keep out of the reach of children.
• Store away from heat and direct light.
• Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
• Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

Your doctor should check your progress at regular visits to make sure that this medicine is working properly.

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 or implants, it may not work properly while you are taking modafinil and for 1 month after stopping modafinil. Another form of birth control should be used during this time.

Modafinil may cause some people to feel dizzy, to have changes in thinking, to have difficulty controlling movements, or to have blurred vision. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous.

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.

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 reduce gradually the amount you are taking before you stop completely.

Along with its needed effects, a medicine 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 as soon as possible if any of the following side effects occur:

• Less common
  • Blurred vision or other vision changes;  chills or fever;  clumsiness or unsteadiness;  confusion;  dizziness or fainting;  increased thirst and increased urination;  mental depression;  problems with memory;  rapidly changing moods;  shortness of breath;  sore throat;  trouble in urinating;  uncontrolled movements of the face, mouth, or tongue 
  
  

• Symptoms of overdose--may be more severe than side effects seen with regular doses or several symptoms may occur together
  • Agitation or excitement;  fast or pounding heartbeat;  increased blood pressure;  trouble in sleeping 
  
  

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

• More common
  • Anxiety;  headache;  nausea;  nervousness;  trouble in sleeping 
  
  

• Less common
  • Decrease in appetite;  diarrhea;  dryness of mouth;  dryness of skin;  flushing or redness of skin;  muscle stiffness;  stuffy or runny nose;  tingling, burning, or prickling sensations in the skin;  trembling or shaking;  vomiting 
  
  

After you stop using this medicine, your body may need time to adjust. The length of time this takes depends on the amount of medicine you were using and how long you used it. During this period of time check with your doctor if you have any disturbing or uncomfortable side effects.

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.