Precautions

Drug information provided by: Merative, Micromedex®

It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly and does not cause any unwanted effects.

Do not use phentermine if you are also using similar medicines such as benzphetamine, diethylpropion, mazindol, phendimetrazine, Bontril®, or Didrex®. Do not use this medicine if you also take an MAO inhibitor (MAOI), such as isocarboxazid (Marplan®), phenelzine (Nardil®,), selegiline (Eldepryl®), or tranylcypromine (Parnate®), or if you have used an MAOI within the past 14 days. Using these medicines together may cause serious unwanted effects.

Using this medicine while you are pregnant can harm your unborn baby. Use an effective form of birth control to keep from getting pregnant. If you think you have become pregnant while using this medicine, tell your doctor right away.

This medicine may be habit-forming. If you think this medicine is not working properly after you have taken it for a few weeks, do not increase the dose. Instead, check with your doctor.

This medicine may cause pulmonary hypertension (increased blood pressure in the lungs). Serious heart or blood vessel problems (eg, valvular heart disease) may also occur if you take more of it, if you take it for a longer time, or if you are taking other medicine that reduces appetite (eg, dexfenfluramine (Redux®), fenfluramine (Fintepla®)). Check with your doctor right away if you have chest pain, decreased ability to exercise, fainting, swelling of the feet or lower legs, or trouble breathing.

This medicine may cause some people to become dizzy, lightheaded, or less alert than they are normally. Do not drive or do anything else that could be dangerous until you know how this medicine affects you.

This medicine may affect blood sugar levels. Patients with diabetes may notice a change in blood or urine sugar tests. Check with your doctor if you have any questions.

Avoid drinking alcohol while you are using this medicine.

Symptoms of an overdose include: bigger, dilated, or enlarged pupils (black part of the eye), confusion, increased sensitivity of the eyes to light, overactive reflexes, panic states, physical attempt to injure, restlessness, seeing, hearing, or feeling things that are not there, shakiness in the legs, arms, hands, or feet, trembling or shaking of the hands or feet, violent actions.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription and nonprescription (over-the-counter) medicines, dietary supplements, herbal remedies, or medicines for appetite control, asthma, colds, cough, hay fever, and sinus problems.

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Portions of this document last updated: March 01, 2024

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