Can phentermine (Adipex-P) be used?

From the Guidelines

Phentermine can be used for short-term weight management in adults with obesity or overweight with weight-related complications, in conjunction with lifestyle modifications, as suggested by the AGA with a conditional recommendation and low-quality evidence 1. The typical dose of phentermine ranges from 15-37.5 mg taken once daily in the morning before breakfast or 1-2 hours after breakfast. Phentermine is a controlled substance (Schedule IV) that works by suppressing appetite through stimulating the central nervous system and increasing norepinephrine levels in the brain. Some key points to consider when using phentermine include:

• It should not be used by people with heart disease, uncontrolled high blood pressure, hyperthyroidism, glaucoma, history of drug abuse, or during pregnancy 1.
• Common side effects include dry mouth, insomnia, constipation, and increased heart rate.
• The medication is not intended for cosmetic weight loss and should be used alongside diet and exercise changes.
• Most providers limit phentermine use to 12 weeks due to concerns about tolerance and decreased effectiveness with longer use, although some practitioners may use it off-label for longer periods 1. It's essential to monitor blood pressure and heart rate periodically while taking phentermine, as it can cause an increase in these parameters 1. Overall, the use of phentermine for weight management should be carefully considered and monitored by a healthcare provider, taking into account the potential benefits and risks, as well as the individual patient's medical history and health status.

From the FDA Drug Label

The usual adult dose is 15 mg to 30 mg at approximately 2 hours after breakfast for appetite control. Phentermine is indicated only as short-term (a few weeks) monotherapy for the management of exogenous obesity Phentermine is not recommended for use in patients 16 years of age and under. History of cardiovascular disease (e.g., coronary artery disease, stroke, arrhythmias, congestive heart failure, uncontrolled hypertension) During or within 14 days following the administration of monoamine oxidase inhibitors Hyperthyroidism Glaucoma Agitated states History of drug abuse Pregnancy Nursing Known hypersensitivity, or idiosyncrasy to the sympathomimetic amines

Phentermine can be used for the management of exogenous obesity in adults, with a usual dose of 15 mg to 30 mg at approximately 2 hours after breakfast for appetite control. However, it is not recommended for use in patients with certain conditions, such as cardiovascular disease, hyperthyroidism, glaucoma, agitated states, history of drug abuse, pregnancy, nursing, or known hypersensitivity to sympathomimetic amines. Additionally, it is not recommended for use in patients 16 years of age and under. Phentermine should be used with caution in patients with mild hypertension and in patients on insulin or oral hypoglycemic medications for diabetes mellitus. 2, 2, 2

From the Research

Phentermine Usage

• Phentermine is a weight loss medication that can be used for the treatment of obesity and hypertension 3.
• However, sympathomimetic medications like phentermine should be avoided in patients with cardiovascular disease (CVD) due to safety concerns 4.
• Recent research suggests that phentermine use is associated with clinically significant weight loss in adults and is generally well-tolerated, with no increased risk of cardiovascular events or elevations in blood pressure 5.
• Phentermine/topiramate has been shown to reduce body weight, blood pressure, blood sugar levels, and lipid levels, but increases the risk of nervous system-related adverse events 6.

Safety and Efficacy

• The long-term effects of phentermine on mortality and morbidity are unknown, and more research is needed to assess its safety and efficacy 7.
• Phentermine/topiramate has been shown to be effective in reducing body weight, but its safety profile is a concern, with increased risk of adverse events such as dysgeusia, paresthesia, and dry mouth 6.
• The European Medicines Agency refused marketing authorization for phentermine/topiramate due to safety concerns, highlighting the need for careful consideration of its use 7.

Clinical Considerations

• Clinicians may consider using phentermine long-term in selected patients, if such prescribing is consistent with local regulatory statutes 5.
• However, the use of phentermine should be carefully evaluated in patients with CVD, and alternative medications such as orlistat, lorcaserin, and liraglutide may be more appropriate due to their safer profiles 4.
• Further research is needed to fully understand the benefits and risks of phentermine and to inform clinical decision-making 3, 7.