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- What is phentermine?
- What brand names are available for phentermine?
- Is phentermine available as a generic drug?
- Do I need a prescription for phentermine?
- Why is phentermine prescribed to patients?
- What are the side effects of phentermine?
- What is the dosage for phentermine?
- Which drugs or supplements interact with phentermine?
- Is phentermine safe to use during pregnancy or while breastfeeding?
- What else should I know about phentermine?
What is the dosage for phentermine?
- The recommended dose is 15-37.5 mg once daily.
- Adipex-P is administered about 1-2 hours after breakfast.
- The lowest effective dose should be used and evening doses should be avoided because phentermine causes insomnia.
Which drugs or supplements interact with phentermine?
- Phentermine is similar to amphetamine and may share some of the interactions associated with amphetamines. Combining phentermine with tricyclic antidepressants (for example, amitriptyline [Elavil, Endep]) or monoamine oxidase inhibitors or MAOIs (for example, phenelzine [Nardil], selegiline [Zelapar, Emsam, and Eldepryl], tranylcypromine [Parnate]) may result in high blood pressure and other serious reactions because of elevated serotonin levels in the blood. Phentermine should not be used within 14 days after stopping a monoamine oxidase inhibitor.
- People with diabetes being treated with phentermine may require a reduction in their dose of insulin or oral hypoglycemic drug.
- Combining alcohol with phentermine may result in an adverse drug reaction.
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
Need help identifying pills and medications?
Use the pill identifier tool on RxList.