Phentermine is used for a limited period of time to speed weight loss in overweight people who are exercising and eating a low-calorie diet. Phentermine is in a class of medications called anorectics. It works by decreasing appetite.
Phentermine comes as tablets and extended-release capsules. It usually is taken as a single daily dose in the morning or three times a day 30 minutes before meals. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take phentermine exactly as directed.
Most people takephentermine for 3-6 weeks; the length of treatment depends on how you respond to the medication. Phentermine can be habit-forming. Do not take a larger dose, take it more often, or take it for a longer period than your doctor tells you to.
If you are taking the extended-release (long-acting) tablets, do not split, chew, or crush them tablet. There are some tablets that can be crushed and mixed with food.
This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.
talk to your doctor about the risks and benefits of taking phentermine if you are 65 years of age or older. Older adults should not usually take phentermine because it is not as safe as other medications that can be used to treat the same condition.
Follow the diet and exercise program your doctor has given you. Phentermine works best in combination with a diet program.
Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.
dry mouth
unpleasant taste
diarrhea
constipation
vomiting
increased blood pressure
heart palpitations
restlessness
dizziness
tremor
insomnia
shortness of breath
chest pain
dizziness
swelling of the legs and ankles
difficulty doing exercise that you have been able to do
Phentermine may cause other side effects. Call your doctor if you have any unusual problems during your treatment with phentermine.
If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online [at http://www.fda.gov/Safety/MedWatch] or by phone [1-800-332-1088].
Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.
In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.
Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your response to phentermine.
Do not let anyone else take your medication. Phenteramine is a controlled substance. Prescriptions may be refilled only a limited number of times; ask your pharmacist any questions you have about refilling your prescription.
It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.
Last Revised - 10/15/2011
AHFS® Consumer Medication Information. © Copyright, 2012. The American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.