• Phentermine is used to treat obesity in people with risk factors such as high blood pressure, or high cholesterol. It is used in people who are significantly overweight and have not been able to lose enough weight with diet and exercise alone.

How should you take this medication?

• Take this medicine with a full glass of water. It is best to take Phentermine on an empty stomach, if you are taking Phentermine one time a day, take your dose in the morning1 hour before breakfast .
   
• Do not crush, chew, break, or open an extended-release capsule. Swallow the pill whole.
   
• If you miss a dose of this medicine, skip the missed dose and continue with your regular dosing schedule. Do not double doses.

General Precautions with Phentermine

• Taking phentermine together with other diet medications such as fenfluramine or dexfenfluramine can cause a rare fatal lung disorder called pulmonary hypertension. Do not take phentermine with any other diet medications without your doctors advice.
   
• If a pregnant woman takes this medicine in high doses or more often than the doctor has directed, it may cause withdrawal symptoms in the newborn baby. Also, medicines similar to sympathomimetic appetite suppressants can cause birth defects in the newborn baby if a pregnant woman takes them in high doses. Before taking this medicine, make sure your doctor knows if you are pregnant or if you may become pregnant.

What are the possible side effects of Phentermine?

• Stop using phentermine and call your doctor at once if you have any of these serious side effects: chest pain,  fainting, fast heartbeat, shortness of breath, swelling of the legs and feet, tremor.
   
• Check with your doctor if you have any of these common side effect: dry mouth,  change in sexual ability or interest, constipation, diarrhea, difficulty sleeping; dizziness, headache, nervousness, upset stomach.