Phentermine is used along with a doctor-approved, reduced-calorie diet, exercise, and behavior change program to help you lose weight. It is used in people who are significantly overweight (obese) and have not been able to lose enough weight with diet and exercise alone. Losing weight and keeping it off can reduce the many health risks that come with obesity, including heart disease, diabetes, high blood pressure, and a shorter life.
It is not known how this medication helps people to lose weight. It may work by decreasing your appetite, increasing the amount of energy used by your body, or by affecting certain parts of the brain. This medication is an appetite suppressant and belongs to a class of drugs called sympathomimetic amines.
How To Use
Take this medication by mouth, usually once a day 1 hour before breakfast or 1-2 hours after breakfast or as directed by your doctor. The tablet form may be taken at a lower dose (8 milligrams) up to 3 times a day 30 minutes before meals. Taking this medication late in the day may cause trouble sleeping (insomnia).
If you are using sustained-release capsules, swallow the medication whole. Do not crush or chew the sustained-release capsules. Doing so can destroy the long action of the drug and may increase side effects.
The dosage is based on your medical condition and response to therapy. Your doctor will adjust the dose to find the best dose for you. Use this medication regularly and exactly as prescribed in order to get the most benefit from it. To help you remember, take it at the same time(s) each day.
This medication is usually taken for only a few weeks at a time. It should not be taken with other appetite suppressants (see also Drug Interactions section). The possibility of serious side effects increases with longer use of this medication and use of this drug along with certain other diet drugs.
This medication may cause withdrawal reactions, especially if it has been used regularly for a long time or in high doses. In such cases, withdrawal symptoms (such as depression, severe tiredness) may occur if you suddenly stop using this medication. To prevent withdrawal reactions, your doctor may reduce your dose gradually. Consult your doctor or pharmacist for more details, and report any withdrawal reactions immediately.
Rarely, abnormal drug-seeking behavior (addiction) is possible with this medication. Do not increase your dose, take it more frequently, or use it for a longer time than prescribed. Properly stop the medication when so directed.
This medication may stop working well after you have been taking it for a few weeks. Talk with your doctor if this medication stops working well. Do not increase the dose unless directed by your doctor. Your doctor may direct you to stop taking this medication.