Phentermine is a sympathomimetic anorectic agent used as a short-term adjunct therapy that is included in a regimen of weight reduction in cases of obesity. It is available only with a doctors prescription and is used with a doctor-approved exercise, behavior change, and reduced-calorie diet program to help you lose weight. Phentermine shows a dose-dependent pharmacokinetic profile. After oral administration of a dose of 15 mg, the maximal concentration was achieved after 6 hours, and its bioavailability was not affected by the consumption of high-fat meals.
Phentermine side effects can be mild or serious. Mild side effects include restlessness, feeling intense excitement or happiness, feeling uneasy, trouble sleeping, nausea, dizziness, tremors, diarrhea, dry mouth and tongue, bad taste in your mouth, constipation, headaches, and others. Serious side effects include high blood pressure, chest pain, decreased ability to exercise, dizziness, fainting, fast, irregular, pounding, or racing heartbeat or pulse, headache, numbness or tingling in the arms or legs, swelling of the feet or lower legs, trembling or shaking of the legs, trouble breathing, trouble with thinking, speaking, or walking, and others.
Phentermine should not be taken with other diet medications such as fenfluramine (Phen-Fen) or dexfenfluramine (Redux) as it can cause a rare fatal lung disorder called pulmonary hypertension. It should also not be taken with monoamine oxidase inhibitors (MAOIs), such as isocarboxazid, phenelzine, rasagiline, selegiline, and tranylcypromine, or if you have used an MAOI within the past 14 days, as taking these drugs together can cause a hypertensive crisis (a dangerous increase in blood pressure) .
Phentermine may contain inactive ingredients that can cause allergic reactions or other problems, so it is important to talk to your pharmacist for more details. If you experience any side effects, mild or serious, you should talk to your doctor or pharmacist. This is not a complete list of side effects, and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
