Modafinil is a medication frequently used to help prevent excessive sleepiness in those with narcolepsy, sleep apnea, or shift work sleep disorder. One of the most common and worrisome modafinil side effects is drug dependency, though this medication is not known to cause physical withdrawal symptoms when stopped. Other potential adverse reactions can include nausea and dry mouth, depression and anxiety, and flu-like symptoms.
As is true with many medications, modafinil may cause some undesirable reactions. Most modafinil side effects are mild, but may be considered irritating by some. Headaches are a common side effect of this drug, as are back pains and feelings of nervousness. Some may also experience stomach or digestion upsets such as diarrhea, nausea, and heartburn, as well as more general complaints like insomnia, dizziness, and a stuffy or runny nose. In some cases, people will also develop a noticeable tingling or prickling sensation, sore throat, sleep disturbances, or loss of appetite.
Though these modafinil side effects may be less common, some people may still experience reactions such as high or low blood pressure and irregular heartbeat, tense or uncoordinated muscles, fainting, or water retention. In more severe cases, people may develop nosebleeds, vision problems, or oral or genital lesions associated with the herpes simplex virus. These reactions are not thought to be typical, and are said to only occur in 1% to 4% of those taking this drug.
Some modafinil side effects are more severe than others. Mood swings that include feelings of depression, an exaggerated sense of well-being, or extreme nervousness may occur while taking this medication. These mood swings may also be accompanied by suicidal actions or thoughts. Allergic reactions may develop in some and will often present as a swelling of the mouth, neck, or face, difficulty swallowing or breathing, and a tightness in the chest.
Other severe modafinil side effects can include prolonged muscle spasms, chest pain in conjunction with a rapid heart rate or unusually high blood pressure, and blood in the urine. Some may also experience a yellowing of the eyes or skin, skin irritations like peeling or blistering, or feelings of confusion. In some cases, people may develop a dependence, and this may present as a frequent desire to increase the dosage of medication. Should any of these side effects occur or become persistent, it is important to speak with a medical professional.