Many people think of methamphetamine as an illegal street drug. However, methamphetamine is also a prescription drug licensed to treat legitimate health problems. Sold under the brand name Desoxyn^®, the medication is used for treating ADHD and obesity. Although methamphetamine is a stimulant, it can produce a calming effect in people with ADHD when it is taken at an appropriate dosage. The medication can also suppress appetite for a short period of time, helping people to lose weight. Side effects of the drug may include headache, high blood pressure, and insomnia. Methamphetamine, which comes as 5 mg oral tablets, should only be taken as prescribed to reduce the risk of becoming addicted to the medication.