Similar to most other prescription medications, there are some common side effects that people should be aware of before they begin to take this prescription on a regular basis. Some of the most common side effects consists of experiencing headaches, nausea, nervousness, insomnia and anxiety, upper respiratory tract infection and mild skin reactions. Therefore, it is important to note that this medication should only be obtained through a physician that’s familiar with their patient’s medical history. In most patients who use this drug however, the only real side effect manifests itself in the form of a headache (from dehydration, as Modafinil is a stimulant and diuretic). Eat a regular diet and drink plenty of water while taking Modafinil, and you’ll find that almost no side effects occur.