Phentermine (Adipex-P, Lomaira): Uses, Side Effects, Interactions, Pictures, Warnings & Dosing - WebMD (original) (raw)

Overview: Phentermine is used short-term to help with weight loss in people who have obesity or are overweight. Common side effects include fast heartbeat, high blood pressure, and restlessness. Serious side effects may rarely include heart valve problems and increased blood pressure in the lungs. Phentermine is a controlled substance because it can be misused or lead to dependence.

What is phentermine used for?

Phentermine is commonly used short-term to help with weight loss in people who have obesity or who are overweight and have other health conditions, such as high blood pressure, diabetes, or high cholesterol.

Phentermine may also be used for other conditions as determined by your healthcare provider.

How does phentermine work (mechanism of action)?

Phentermine may work by interacting with certain chemicals in the brain to reduce your appetite.

How is phentermine supplied (dosage forms)?

Brands and other names

Dosage forms and strengths

How should I store phentermine?

Phentermine should be stored at room temperature, between 68 F to 77 F (20 C to 25 C). It can be exposed to temperatures between 59 F to 86 F (15 C to 30 C), for shorter periods of time, such as when transporting it. Store in a cool, dry place.

Side Effects

What are the most common side effects of phentermine?

The most common side effects of phentermine are listed below. Tell your healthcare provider if you have any of these side effects that bother you.

There may be other side effects of phentermine that are not listed here. Contact your healthcare provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of phentermine?

While less common, the most serious side effects of phentermine are described below, along with what to do if they happen.

Increased Blood Pressure in the Lungs (Pulmonary Arterial Hypertension). Rarely, phentermine may increase blood pressure in your lungs, which can lead to death. Stop taking phentermine and call your healthcare provider right away if you have any of the following symptoms of pulmonary arterial hypertension.

Heart Valve Problems (Valvular Heart Disease). Rarely, phentermine may cause heart valve disease. Your heart valves open and close like doors as your heart beats to keep your blood flowing in the right direction. Call your healthcare provider right away if you have any of the following symptoms of heart valve disease.

Risk of Misuse and Tolerance. Phentermine can cause tolerance, which means your body gets used to a medicine and it seems to stop working for you. Misusing phentermine can lead to serious side effects like hallucinations or psychotic-like behaviors. Misuse means taking a medicine in a way other than how it was prescribed. Take phentermine exactly as prescribed. Tell your healthcare provider if you feel that phentermine is not working. Tell your healthcare provider right away if you have any of the following symptoms, or if you have been told by others you have these symptoms.

Severe Allergic Reactions. Phentermine may cause allergic reactions, which can be serious. Stop taking phentermine and get help right away if you have any of the following symptoms of a serious allergic reaction.

Changes in Alertness or Coordination. Phentermine can affect your alertness or coordination. Do not drive or do other activities that require alertness or coordination until you know how phentermine affects you.

Warnings & Precautions

Who should not use phentermine?

Allergies to Ingredients. People who are allergic to any of the following should not take phentermine.

Your pharmacist can tell you all of the ingredients in the specific phentermine products they stock.

Heart Problems or Stroke. You should not take phentermine if you have or have had certain heart problems, such as coronary artery disease (CAD), an abnormal heart rhythm (arrhythmia), uncontrolled high blood pressure (hypertension), or a stroke.

Overactive Thyroid (Hyperthyroidism). Phentermine should not be taken if you have an overactive thyroid.

Glaucoma. Phentermine should not be taken if you have glaucoma.

Agitation. Phentermine should not be taken if you are feeling agitated, restless, or have uncontrolled anger.

Substance Use Disorder. Phentermine is a controlled substance and may be misused or lead to dependence. You should not use phentermine if you have a history of substance use disorder.

Pregnancy. Do not take phentermine if you are pregnant. If you become pregnant, contact your healthcare provider right away. See the Pregnancy section for more details.

Breastfeeding. Do not take phentermine if you are breastfeeding. You must either stop breastfeeding or stop phentermine. See the Breastfeeding section for more details.

Drug Interactions. Phentermine should not be taken while you are using certain other medicines. Before taking phentermine, tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

What should I know about phentermine before using it?

Do not take phentermine unless it has been prescribed to you by a healthcare provider. Take it as prescribed.

Do not share phentermine with other people, even if they have the same condition as you. It may harm them.

Keep phentermine out of the reach of children. Phentermine is a controlled substance because it can be misused or lead to dependence. Store phentermine in a safe place to protect it from theft. It is illegal to sell or give away this medicine.

Phentermine can affect your alertness or coordination. Do not drive or do other activities that require alertness or coordination until you know how phentermine affects you.

People who are 65 or older can be at greater risk for some side effects of phentermine. Talk to your healthcare provider about your risks if you are in this age group.

Phentermine should not be taken later in the evening, as it can lead to trouble sleeping.

What should I tell my healthcare provider before using phentermine?

Tell your healthcare provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if phentermine is right for you.

In particular, make sure that you discuss any of the following.

Kidney Problems. You may need a lower dose of phentermine if your kidneys are not working as well as they should be. If there is a concern about the health of your kidneys, your healthcare provider may do tests to determine if they are working well enough to take this medicine.

High Blood Pressure. Phentermine can increase your blood pressure. Tell your healthcare provider if you have high blood pressure, even if it is only just a little bit high.

Pregnancy. Phentermine should not be taken if you are pregnant. Weight loss is not recommended during pregnancy, even if you are overweight. Weight loss during pregnancy may cause harm to an unborn baby. Tell your healthcare provider if you are or plan to become pregnant.

Breastfeeding. It is not known if phentermine passes into breast milk. Tell your healthcare provider if you are breastfeeding or plan to breastfeed. Your healthcare provider will advise you if you should stop breastfeeding or stop phentermine.

Interactions

Does phentermine interact with foods or drinks?

There are no known interactions between phentermine and foods or drinks.

Drinking alcohol while taking phentermine may increase your risk for certain side effects, like dizziness. It is best to limit the amount of alcohol you drink while taking phentermine.

Does phentermine interact with other medicines (drug interactions)?

Always tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before taking phentermine.

This may not be a complete list of medicines that can interact with phentermine. Always check with your healthcare provider.

Does Phentermine (Adipex-P, Lomaira) interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much phentermine?

If you or someone else has taken too much phentermine, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of phentermine?

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and only take the next dose. Do not take double or extra doses.

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