This information from Lexicomp® explains what you need to know about this medication, including what it’s used for, how to take it, its side effects, and when to call your healthcare provider.
Brand Names: US
Adipex-P; Lomaira
Brand Names: Canada
RHO-Phentermine
What is this drug used for?
- It is used for weight loss.
What do I need to tell my doctor BEFORE I take this drug?
- If you are allergic to this drug; any part of this drug; or any other drugs, foods, or substances. Tell your doctor about the allergy and what signs you had.
- If you have ever had any of these health problems: Heart disease like heart failure or a heartbeat that is not normal, drug abuse, high blood pressure, or stroke.
- If you have any of these health problems: Glaucoma, agitation, anxiety, or overactive thyroid.
- If you have kidney disease or are on dialysis.
- If you have taken certain drugs for depression or Parkinson’s disease in the last 14 days. This includes isocarboxazid, phenelzine, tranylcypromine, selegiline, or rasagiline. Very high blood pressure may happen.
- If you are taking any of these drugs: Fluoxetine, fluvoxamine, linezolid, methylene blue, paroxetine, or sertraline.
- If you are taking any other drug (prescription or OTC, natural product) for weight loss.
- If you are pregnant or may be pregnant. Do not take this drug if you are pregnant.
- If you are breast-feeding. Do not breast-feed while you take this drug.
This is not a list of all drugs or health problems that interact with this drug.
Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take this drug with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.
What are some things I need to know or do while I take this drug?
- Tell all of your health care providers that you take this drug. This includes your doctors, nurses, pharmacists, and dentists.
- Avoid driving and doing other tasks or actions that call for you to be alert until you see how this drug affects you.
- Do not take this drug for longer than you were told by your doctor.
- If you have been taking this drug for a long time or at high doses, it may not work as well and you may need higher doses to get the same effect. This is known as tolerance. Call your doctor if this drug stops working well. Do not take more than ordered.
- If you have been taking this drug for many weeks, talk with your doctor before stopping. You may want to slowly stop this drug.
- This drug may be habit-forming; avoid long-term use. Tell your doctor if you have a history of drug or alcohol abuse.
- You may need to have some heart tests before starting this drug. If you have questions, talk with your doctor.
- Check blood pressure and heart rate as the doctor has told you.
- If you have high blood sugar (diabetes) and take drugs to lower blood sugar, talk with your doctor. Weight loss may raise the chance of low blood sugar if you take drugs to lower blood sugar. Call your doctor right away if you have signs of low blood sugar like dizziness, headache, feeling sleepy, feeling weak, shaking, a fast heartbeat, confusion, hunger, or sweating.
- Follow the diet and exercise plan that your doctor told you about.
- Talk with your doctor before you drink alcohol.
- Do not give to a child younger than 17 years of age.
What are some side effects that I need to call my doctor about right away?
WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:
- Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
- Signs of high blood pressure like very bad headache or dizziness, passing out, or change in eyesight.
- Change in how you act.
- Mood changes.
- Shakiness.
- Rarely, people taking drugs for weight loss like this drug have had heart valve problems or raised pressure in the lungs. Raised pressure in the lungs is often deadly. Call your doctor right away if you have dizziness or passing out, tiredness, or weakness that will not go away; fast or abnormal heartbeat; chest pain; shortness of breath; or swelling in your arms or legs. Call your doctor right away if you are not able to exercise as much.
What are some other side effects of this drug?
All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:
- Dizziness or headache.
- Feeling nervous and excitable.
- Diarrhea or constipation.
- Dry mouth.
- Trouble sleeping.
- Bad taste in your mouth.
- Lowered interest in sex.
- Not able to get or keep an erection.
- Restlessness.
These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.
You may report side effects to your national health agency.
You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at https://www.fda.gov/medwatch.
How is this drug best taken?
Use this drug as ordered by your doctor. Read all information given to you. Follow all instructions closely.
- Some products are taken 1 time a day, either before breakfast or 1 to 2 hours after breakfast. Some products are taken more than 1 time a day, 30 minutes before meals. Be sure you know how to take this drug.
- Avoid taking this drug late in the evening to prevent sleep problems.
What do I do if I miss a dose?
- Take a missed dose as soon as you think about it.
- If it is close to the time for your next dose, skip the missed dose and go back to your normal time.
- Do not take 2 doses at the same time or extra doses.
How do I store and/or throw out this drug?
- Store at room temperature in a dry place. Do not store in a bathroom.
- Store this drug in a safe place where children cannot see or reach it, and where other people cannot get to it. A locked box or area may help keep this drug safe. Keep all drugs away from pets.
- Throw away unused or expired drugs. Do not flush down a toilet or pour down a drain unless you are told to do so. Check with your pharmacist if you have questions about the best way to throw out drugs. There may be drug take-back programs in your area.
General drug facts
- If your symptoms or health problems do not get better or if they become worse, call your doctor.
- Do not share your drugs with others and do not take anyone else’s drugs.
- Some drugs may have another patient information leaflet. If you have any questions about this drug, please talk with your doctor, nurse, pharmacist, or other health care provider.
- Some drugs may have another patient information leaflet. Check with your pharmacist. If you have any questions about this drug, please talk with your doctor, nurse, pharmacist, or other health care provider.
- If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.
Consumer Information Use and Disclaimer
This generalized information is a limited summary of diagnosis, treatment, and/or medication information. It is not meant to be comprehensive and should be used as a tool to help the user understand and/or assess potential diagnostic and treatment options. It does NOT include all information about conditions, treatments, medications, side effects, or risks that may apply to a specific patient. It is not intended to be medical advice or a substitute for the medical advice, diagnosis, or treatment of a health care provider based on the health care provider’s examination and assessment of a patient’s specific and unique circumstances. Patients must speak with a health care provider for complete information about their health, medical questions, and treatment options, including any risks or benefits regarding use of medications. This information does not endorse any treatments or medications as safe, effective, or approved for treating a specific patient. UpToDate, Inc. and its affiliates disclaim any warranty or liability relating to this information or the use thereof. The use of this information is governed by the Terms of Use, available at https://www.wolterskluwer.com/en/know/clinical-effectiveness-terms.
Last Reviewed Date
2024-01-29
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