The usual dosage for the management of fatigue in MS is 100-200 mg daily, taken in the earlier part of the day in order to avoid sleep disturbance. If you miss a dose of modafiinil and remember it before 12 noon the next day, take the missed dose as soon as possible. If you remember it after 12 noon , skip the missed dose so that the medication will not make it difficult for you to sleep at night.
The precautions listed here pertain to the use of this medication as a treatment for narcolepsy. Since modafinil has not been approved by the FDA for use in multiple sclerosis, there are no precautions specific to MS-related uses of the drug.
The Food and Drug Administration (FDA) has added a warning to the labeling of modafinil. During the clinical trials of modafinil for daytime sleepiness, serious rashes requiring hospitalization were reported in children taking modafinil; no serious rashes were reported in adults. Following those trials, rare cases of serious or life-threatening rashes have been reported in children and adults. In addition, multi-organ sensitivity (allergic) reactions have also been reported, as well as psychiatric reactions, including mania, delusions, hallucinations, and suicidal thoughts. While it is difficult to determine from these post-marketing reports what the exact relationship is between modafinil and these problems, you are advised to contact your physician if you experience a rash, chest pain, depression, anxiety, or signs of psychosis or mania.
Tell your physician if you have ever had an unusual or allergic reaction to any other nervous system stimulant such as Ritalin® or Dexedrine®.
This medication may cause some people to become dizzy or confused, or to have blurred vision or difficulty controlling movements. Make sure you know how you react to this medication before driving a car or engaging in any other potentially dangerous activity.
If you think that the modafinil is not working properly after you have taken it for a few weeks, speak to your physician. Do not increase the dose.
If you are using a medication for birth control such as birth control pills or implants, it may not work effectively in combination with modafinil or for one month after you have stopped taking modafinil. During this time, an additional form of birth control should be used.
Studies of the effects of modafinil in pregnancy have not been done in humans. Studies in animals, however, suggest that the use of modafinil may result in unsuccessful pregnancies or cause birth defects. Before taking this medication, make sure your physician knows if you are pregnant or planning to become pregnant.
It is not known whether modafinil passes into breast milk. If you are taking modafinil and wish to breastfeed, you should discuss this with your physician.
When taking modafinil, it is especially important for your physician to know if you are taking any of the following medications that may add to the stimulating effects of modafinil such as irritability, nervousness, trembling or shaking, insomnia:
- Bupropion (e.g., Wellbutrin®; Zyban®)
- Medicine for asthma or other breathing problems
- Medicine for colds, sinus problems, hay fever (including nose drops or sprays)
- Methylphenidate (e.g., Ritalin®)
or, any of the following drugs whose action or effectiveness might be affected by the modafinil:
- Diazepam (e.g., Valium®)
- Phenytoin (e.g., Dilantin®)
- Propranolol (e.g., Inderal®)
- Warfarin (e.g., Coumadin®)
or, any of the following drugs that may cause problems when combined with modafinil:
- Monoamine oxidase (MAO) inhibitors
- Tricyclic antidepressants (e.g., Elavil®; Anafranil®; Tofranil®; Aventyl®)
or, any of the following substances that may add to the stimulating effects of modafinil:
Possible Side Effects
The side effects listed here pertain to the use of modafinil as a treatment for narcolepsy. There are no reports at the present time of the side effects associated with the use of this drug in the treatment of MS-related fatigue.
Side effects that may go away as your body adjusts to the medication and do not require medical attention unless they continue or are bothersome: anxiety; headache; nausea; nervousness; trouble sleeping; decrease in appetite; diarrhea; dryness of mouth; flushing or redness of skin; muscle stiffness*; stuffy or runny nose; tingling*; burning, trembling or shaking*; vomiting.
Rare side effects that should be reported as soon as possible to your physician: blurred vision* or other vision changes; chills or fever; clumsiness or unsteadiness* confusion; dizziness or fainting; increased thirst and increased urination; depression; problems with memory*; rapidly changing moods; shortness of breath; difficulty with urination; uncontrolled movements in the face, mouth, or tongue.
*Since it may be difficult to distinguish between certain common symptoms of MS and some side effects of modafinil, be sure to consult your physician if an abrupt change of this type occurs.
Reprinted with permission from Rosalind C. Kalb (ed.), Multiple Sclerosis: The Questions You Have—The Answers You Need (4th ed.). New York: Demos Medical Publishing, 2007.