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Phentermine Dosage

Medically reviewed on October 4, 2017.

Applies to the following strengths: 30 mg; 15 mg; 37.5 mg; 8 mg; 18.75 mg; resin 15 mg; resin 30 mg

Usual Adult Dose for:

Usual Pediatric Dose for:

Additional dosage information:

Usual Adult Dose for Obesity

8 mg orally 3 times a day 30 minutes before meals, OR
15 to 37.5 mg orally once a day before breakfast or 1 to 2 hours after breakfast.

Use: Short-term (a few weeks) adjunct in a regimen of weight reduction based on exercise, behavioral modification, and caloric restriction in the management of exogenous obesity in patients with an initial body mass index (BMI) of 30 kg/m2 or greater, or BMI of 27 kg/m2 or greater in the presence of other risk factors (e.g., controlled hypertension, diabetes, hyperlipidemia).

Usual Pediatric Dose for Obesity

Age 17 Years and Older:
8 mg orally 3 times a day 30 minutes before meals, OR
15 to 37.5 mg orally once a day before breakfast or 1 to 2 hours after breakfast.

Use: Short-term (a few weeks) adjunct in a regimen of weight reduction based on exercise, behavioral modification, and caloric restriction in the management of exogenous obesity in patients with an initial body mass index (BMI) of 30 kg/m2 or greater, or BMI of 27 kg/m2 or greater in the presence of other risk factors (e.g., controlled hypertension, diabetes, hyperlipidemia).

Renal Dose Adjustments

Use with caution; drug exposure increases may occur in those with renal impairment.

Liver Dose Adjustments

Data not available.

Dose Adjustments

Patients Not Requiring a Full Dose:
-Tablets are scored to facilitate administering half of the usual dose.
-Dosing Options: 4 mg orally 3 times a day 30 minutes before meals; 18.75 mg orally once a day before breakfast or 1 to 2 hours after breakfast; OR 18.75 mg orally 2 times a day.

Precautions

Safety and efficacy have not been established in patients younger than 17 years.

Consult WARNINGS section for additional precautions.

US Controlled Substance: Schedule IV

Dialysis

Data not available.

Other Comments

Administration Advice:
-Individualize dosage to obtain an adequate response with the lowest effective dose.
-Avoid late evening administration due to the possibility of resulting insomnia.

Storage Requirements: Store at 20 to 25 degrees Celsius and protect from moisture and light.

General: Consult the manufacturer product information on overdose management.

Monitoring: Development of new, unexplained symptoms of dyspnea, angina pectoris, syncope, or lower extremity edema (during treatment).

Patient Advice: Avoid activities that require mental alertness such as driving and operating machinery until you know how this drug affects you.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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