What are the indications, advantages, and disadvantages of Phentermine (phentermine)?

From the FDA Drug Label

Phentermine Hydrochloride is a sympathomimetic amine anorectic indicated as a short-term adjunct (a few weeks) 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 limited usefulness of agents of this class, including Phentermine hydrochloride, should be measured against possible risk factors inherent in their use. Coadministration with other drugs for weight loss is not recommended (safety and efficacy of combination not established). Rare cases of primary pulmonary hypertension have been reported. Phentermine should be discontinued in case of new, unexplained symptoms of dyspnea, angina pectoris, syncope or lower extremity edema. Rare cases of serious regurgitant cardiac valvular disease have been reported. Tolerance to the anorectic effect usually develops within a few weeks. If this occurs, phentermine should be discontinued. The recommended dose should not be exceeded. Phentermine may impair the ability of the patient to engage in potentially hazardous activities such as operating machinery or driving a motor vehicle. Risk of abuse and dependence. The least amount feasible should be prescribed or dispensed at one time in order to minimize the possibility of overdosage. Concomitant alcohol use may result in an adverse drug reaction. Use caution in patients with even mild hypertension (risk of increase in blood pressure). A reduction in dose of insulin or oral hypoglycemic medication may be required in some patients.

The indications of Phentermine are:

• Short-term adjunct in a regimen of weight reduction based on exercise, behavioral modification, and caloric restriction
• 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

The advantages of Phentermine are:

• Helps with weight reduction
• Can be used in conjunction with exercise, behavioral modification, and caloric restriction

The disadvantages of Phentermine are:

• Risk of abuse and dependence 1
• Contraindicated in certain patients, such as those with a history of cardiovascular disease, hyperthyroidism, glaucoma, agitated states, history of drug abuse, pregnancy, and nursing mothers 1
• May impair the ability to engage in hazardous activities, such as operating machinery or driving a motor vehicle 1
• May interact with other medications, such as monoamine oxidase inhibitors, insulin, and oral hypoglycemics 1
• May cause adverse reactions, such as primary pulmonary hypertension, serious regurgitant cardiac valvular disease, and increased blood pressure 1

From the Research

Introduction to Phentermine

Phentermine is a sympathomimetic amine approved for the short-term treatment of patients with obesity 2. It is commonly used as an adjunct to lifestyle modification for weight loss.

Indications for Phentermine

The primary indication for phentermine is the treatment of obesity in patients who have failed to achieve weight loss through diet and exercise alone. It is typically prescribed for patients with a body mass index (BMI) of 30 or higher, or those with a BMI of 27 or higher with at least one weight-related condition, such as hypertension, diabetes, or hyperlipidemia.

Advantages of Phentermine

The advantages of phentermine include:

• Significant weight loss in adults, with studies suggesting that it is associated with clinically significant weight loss 3
• Generally well-tolerated, with large-scale observational studies evaluating its safety not identifying an increased risk of cardiovascular events or elevations in blood pressure 3
• May be effective for long-term weight loss, although more research is needed to support its efficacy and safety in this context 3
• Can be used in combination with other weight loss medications, such as topiramate, for enhanced weight loss and metabolic benefits 4

Disadvantages of Phentermine

The disadvantages of phentermine include:

• Contraindicated in patients with cardiovascular disease or uncontrolled hypertension due to the potential risk of exacerbating these conditions 2
• May have varying degrees of efficacy and clinical benefit, with some patients experiencing more significant weight loss than others 2
• Requires careful monitoring and screening, including electrocardiograms, to minimize the risk of adverse effects 2
• Has the potential for addiction, although studies have not supported this notion 3

Treatment and Dosage

Phentermine is typically prescribed at a dose of 15-37.5 mg per day, taken orally in the morning. The duration of treatment varies, but it is usually recommended for short-term use, typically up to 12 weeks. However, some studies have suggested that it may be effective for long-term weight loss, and clinicians may consider using it long-term in selected patients, if consistent with local regulatory statutes 3.

Differentials and Caveats

When prescribing phentermine, clinicians should consider the following differentials and caveats:

• Patients with a history of cardiovascular disease or uncontrolled hypertension should be carefully evaluated and monitored due to the potential risk of exacerbating these conditions
• Patients with a history of substance abuse or addiction should be carefully evaluated and monitored due to the potential risk of addiction
• Phentermine should not be used in combination with other medications that may increase the risk of adverse effects, such as monoamine oxidase inhibitors (MAOIs)
• Patients should be carefully monitored for signs of adverse effects, such as increased heart rate, blood pressure, or cardiovascular events.

Conclusion

In conclusion, phentermine is a sympathomimetic amine that is approved for the short-term treatment of patients with obesity. While it has several advantages, including significant weight loss and general tolerability, it also has several disadvantages, including contraindications in patients with cardiovascular disease or uncontrolled hypertension, and the potential for varying degrees of efficacy and clinical benefit. Clinicians should carefully evaluate and monitor patients when prescribing phentermine, and consider the differentials and caveats mentioned above.