Its a sympathomimetic amine, which is similar to an amphetamine. It is also known as an “anorectic” or “anorexigenic” drug.

Adipex stimulates the central nervous system (nerves and brain), which increases your heart rate and blood pressure and decreases your appetite. Adipex is used as a short-term supplement to diet and exercise in the treatment of obesity.

Side Effects may also include:-

Skin abnormalities, insomnia, irritability, hyperactivity, personality changes, and psychosis, difficulty breathing; closing of your throat; swelling of your lips, tongue, or face; or hives.

Symptoms of a Adipex overdose include restlessness, tremor, rapid breathing, confusion, hallucinations, panic, aggressiveness, nausea, vomiting, diarrhea, an irregular heartbeat, and seizures.

A dose taken too late in the day can cause insomnia.

You can not take Adipex, if you have heart disease or high blood pressure, arteriosclerosis, glaucoma or you have taken a monoamine oxidase inhibitor (MAOI) such as isocarboxazid (Marplan), tranylcypromine (Parnate), or phenelzine (Nardil) in the last 14 days and also If you have history of drug or alcohol abuse.Consult with your doctor if you think you are pregnant or before breast-feeding.

Take phentermine exactly as directed by your doctor. If you do not understand these directions, ask your pharmacist, nurse, or doctor to explain them to you.
Take each dose with a full glass of water.

Do not take phentermine in the evening because it may cause insomnia.
Do not crush, chew or open any “once-daily” phentermine tablets or capsules. Swallow them whole.