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What is phentermine?


Phentermine (Adipex-P®) is a prescription drug used for weight loss. This medication serves as an appetite suppressant. Phentermine works by aiding the release chemicals in the brain that control appetite. Phentermine should be used for only short periods (for a few weeks) as part of a physician-guided weight loss program, which includes a reduced calorie diet and exercise. Your doctor should decide if phentermine is right for you based on your weight, height, and any health problems you may have. In combination with a reduced calorie diet, the use of phentermine has been shown to produce additional weight loss. The safety and effectiveness of using phentermine with other drugs for weight loss has not been proven.

Expected weight loss with phentermine

Weight loss is greatest during the first few weeks of therapy but typically levels off with continued use. Weight loss can vary from person to person and phentermine does not work for everyone. Phentermine is typically taken in the morning or 10-14 hours before bedtime to minimize trouble sleeping.

Most common phentermine side effects

Dry mouth, nervousness, constipation, and nausea are the most commonly reported side effects of phentermine. More serious side effects include increased blood pressure and heart rate, anxiety, and blurred vision. You should have your blood pressure checked regularly while taking phentermine. Rarely, heart valve damage and a rare lung disorder called primary pulmonary hypertension (PPH) have been linked to the use of phentermine alone.

Potential risks from drug combinations

Rarely, heart valve damage and a rare lung disorder called primary pulmonary hypertension (PPH) has also shown itself when phentermine is used in combination with certain weight loss medicines like dexfenfluramine (Redux®) and fenfluramine (Pondimin®). These combinations were more commonly known as the "phen-fen" diet. These drugs were removed from the U.S. market due to safety concerns. You should not take phentermine if you have heart disease (coronary artery disease, congestive heart disease, irregular heartbeat, or stroke), thyroid disease, glaucoma, or anorexia. Phentermine is not recommended if you are pregnant or are considering pregnancy. If you have other medical conditions, you should discuss the use of phentermine with your physician.

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