What is the body mass index (BMI) indication for Phentermine (phentermine hydrochloride)?

From the Guidelines

Phentermine is typically prescribed for individuals with a BMI of 30 or higher (indicating obesity) or for those with a BMI of 27 or higher who also have weight-related health conditions such as high blood pressure, high cholesterol, or type 2 diabetes. This medication works as an appetite suppressant by stimulating the central nervous system, increasing heart rate and blood pressure while decreasing appetite.

Key Points to Consider

• Phentermine is intended for short-term use (usually up to 12 weeks) as part of a comprehensive weight management program that includes diet and exercise 1.
• It's essential to note that phentermine carries risks of side effects including increased blood pressure, heart palpitations, insomnia, and potential for dependence.
• Before starting phentermine, patients should undergo a thorough medical evaluation to ensure they don't have conditions that would make the medication unsafe, such as heart disease, hyperthyroidism, glaucoma, or a history of drug abuse 1.
• Regular monitoring by a healthcare provider is crucial while taking this medication to assess its effectiveness and watch for potential side effects.

Important Considerations

• The FDA approved the combination of phentermine immediate release and topiramate extended release for chronic weight management in adults with an initial BMI of 30 kg/m2 or 27 kg/m2 in the presence of at least 1 weight-related complication 1.
• Phentermine should be avoided in patients with a history of cardiovascular disease, and blood pressure and heart rate should be monitored periodically while taking phentermine 1.
• Female patients with child-bearing potential should be counseled on the risks of teratogenicity and consistent use of reliable contraception while using phentermine-topiramate ER 1.

From the FDA Drug Label

Phentermine Hydrochloride, USP 15 mg and 30 mg is indicated as a 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 for patients with an initial body mass index greater than or equal to 30 kg/m 2, or greater than or equal to 27 kg/m 2 in the presence of other risk factors (e.g., controlled hypertension, diabetes, hyperlipidemia).

The body mass index (BMI) indication for Phentermine (phentermine hydrochloride) is:

• Greater than or equal to 30 kg/m^2
• Greater than or equal to 27 kg/m^2 in the presence of other risk factors, such as:
  • Controlled hypertension
  • Diabetes
  • Hyperlipidemia 2, 2, 2

From the Research

Body Mass Index (BMI) Indication for Phentermine

• The BMI indication for Phentermine (phentermine hydrochloride) can be inferred from various studies, including those that investigated its efficacy in weight loss and management of obesity-related comorbidities 3, 4, 5, 6.
• According to the study by 3, Phentermine was administered to overweight or obese adults with a body-mass index (BMI) of 27-45 kg/m(2) and two or more comorbidities.
• Another study by 4 reported the case of a 34-year-old lady with morbid obesity, who had a peak initial body mass index (BMI) of 62.6 kg/m2 and was treated with Phentermine.
• A study published in 5 included subjects with a BMI of 33.8 ± 3.1 kg m(-2), who were treated with Phentermine for 8 weeks.
• Overall, these studies suggest that Phentermine can be used in individuals with a BMI of 27 kg/m2 or higher, including those with morbid obesity 3, 4, 5, 6.

Key Findings

• Phentermine is effective in achieving significant weight loss in individuals with a BMI of 27 kg/m2 or higher 3, 4, 5, 6.
• The medication can be used in combination with lifestyle modifications, such as diet and exercise, to achieve greater weight loss and improve metabolic outcomes 3, 6.
• Higher hunger ratings and lower cognitive restraint may predict greater weight loss with Phentermine treatment 5.