Home Medicines Modafinil: effect, areas of application, side effects

Modafinil: effect, areas of application, side effects

by Josephine Andrews
Published: Last Updated on 98 views

Modafinil is one of the most important drugs against sleeping sickness. However, its approval for other indications such as sleep apnea was withdrawn in 2011 due to an unfavorable benefit-risk profile. Modafinil is generally considered to be well tolerated, but in rare cases it can cause headaches and restlessness. Here’s everything you need to know about Modafinil!

How Modafinil works

Modafinil is a drug from the stimulant class. These are substances with a centrally stimulating effect, which also include amphetamines, for example. However, Modafinil differs from these both pharmacologically (in its effect) and structurally (in its chemical composition).

The exact mechanism of action of modafinil is not yet fully understood. Part of the effect is based on the fact that the active ingredient binds to the docking sites of the neurotransmitter adrenaline – the so-called alpha receptors (α receptors).

Adrenaline is normally responsible for the wakefulness of the body. When it binds to the α-receptors, the central nervous system is activated – the treated person stays awake during the day.

Sleeping sickness (also called narcolepsy) is characterized by sudden sleep attacks. From one moment to the next, those affected have an irresistible urge to sleep during the day, even in inappropriate situations (e.g. at work, when eating or driving). These sleep attacks usually last between 10 and 20 minutes and may or may not be associated with muscle relaxation (cataplexy). Hallucinations sometimes occur while falling asleep .

Those affected suffer greatly from the symptoms because they cannot predict the attacks. Depending on the situation, it can also be dangerous (e.g. if you fall asleep at the steering wheel).

One way of treating narcolepsy is to stimulate the central nervous system (spinal cord, brain ). This is possible with modafinil, among other things. This keeps the person being treated awake during the day.

intake, degradation and excretion

Modafinil is taken by mouth and almost completely (about 90 percent) absorbed from the gut into the blood. The effect kicks in after about an hour.

The excretion of the drug takes a long time. Remains of the active ingredient can still be detected in the body up to a month after ingestion. The breakdown takes place mainly in the liver.

When is Modafinil used?

Modafinil is used in the following area of ​​application (indication):

  • Somnolence with or without skeletal muscle relaxation (narcolepsy with or without cataplexy)

How Modafinil is used

The dosage is 200 to 400 milligrams daily. The active ingredient is swallowed in the form of tablets with plenty of liquid (preferably a large glass of water). It should preferably be taken in the morning so that the waking state extends throughout the day and there are fewer sleep disturbances.

Patients with kidney or liver dysfunction receive a reduced dose.

Very often, i.e. in more than ten percent of those treated, modafinil causes headaches as side effects.

Frequently, i.e. in one to ten percent of those treated, restlessness, insomnia, anxiety, increased sweating and an accelerated heart rate occur after ingestion.

Life-threatening allergic reactions occur very rarely.

If you notice any skin changes during treatment with modafinil, notify a doctor as soon as possible for clarification.

What should be considered when taking Modafinil?


Modafinil should not be taken if:

  • Known hypersensitivity to the active substance
  • uncontrolled moderate to severe high blood pressure (hypertension)
  • cardiac arrhythmias

Particular caution is required in the case of drug addiction or drug abuse, ECG changes and left ventricular hypertrophy (enlargement of the left ventricle).


Modafinil slightly increases the activity of the enzyme CYP3A4 (it is a weak inducer of this enzyme) and moderately inhibits the enzyme CYP2C19. Both enzymes are responsible for breaking down numerous medicinal substances in the body. Modafinil can therefore increase or decrease the metabolism of other drugs taken at the same time and thereby weaken or increase their effect.

This concerns, among other things:

  • antiepileptic drugs (such as phenytoin )
  • tricyclic antidepressants (such as amitriptyline and doxepin )
  • hormonal contraceptives (such as the ” pill “)
  • some sleeping pills and sedatives from the benzodiazepine group (such as diazepam , midazolam, triazolam)

If modafinil is given concomitantly with blood-thinning agents (such as warfarin), blood coagulation should be closely monitored in the first two months of treatment .

Driving and using machines

Modafinil can alter responsiveness because the active ingredient affects the central nervous system. Patients should therefore first observe their individual reaction to the drug at the beginning of therapy. Then they can decide together with the doctor whether they are still able to actively participate in road traffic and operate heavy machinery or not.

age restriction

Modafinil should not be used in children and adolescents under 18 years of age.

pregnancy and breast feeding period

Modafinil drugs should not be taken during pregnancy. There is little experience with use during lactation. That is why the doctor decides on a case-by-case basis.

How to get modafinil medication

Modafinil drugs require a prescription in Germany, Austria and Switzerland.

Since when is Modafinil known?

Modafinil has been in use for decades. Due to an unfavorable risk-benefit profile (reports of very rare life-threatening skin reactions), the drug’s approval for indications other than narcolepsy (e.g. for sleep apnea ) was withdrawn in 2011.

More interesting facts about Modafinil

Modafinil is abusively used to enhance performance, such as before exams or competitions. It is on the list of prohibited doping substances.

Modafinil became known primarily through positive evidence from the track and field athlete Kelli White, who wanted to increase her athletic performance with the active ingredient in 2003.

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