What is the best pharmacological treatment for weight loss in an elderly patient?

From the Guidelines

For elderly patients with weight loss, dronabinol is not recommended due to lack of significant effect on body weight, whereas megestrol acetate (Megace) may be considered as it has shown positive effects on appetite and body weight in some studies. When choosing a medication for weight loss in elderly patients, it is essential to consider the patient's unique behaviors, comorbidities, and potential adverse effects 1. The selection of medication should be based on a comprehensive assessment of the patient's medical conditions, current medications, and frailty status.

Some key points to consider when selecting a medication for weight loss in elderly patients include:

• Close monitoring for side effects, particularly gastrointestinal symptoms and potential nutrient deficiencies
• Modest weight loss goals (5-10% of body weight)
• Regular follow-up appointments to assess efficacy and tolerability
• Consideration of comorbidities like diabetes, cardiovascular disease, and renal function
• Avoidance of medications that may exacerbate weight loss or have adverse effects in elderly patients

According to the most recent study 1, megestrol acetate (Megace) has shown positive effects on appetite and body weight in some studies, although the evidence is not conclusive. In contrast, dronabinol has not been shown to have a significant effect on body weight in elderly patients with dementia. Therefore, megestrol acetate (Megace) may be a better option for elderly patients with weight loss, but its use should be carefully considered and monitored. It is also important to note that lifestyle modifications, such as diet and exercise, should be the cornerstone of obesity management, and pharmacotherapy should be used as an adjunct to these modifications 1.

From the FDA Drug Label

In elderly patients or patients unable to tolerate 2.5 mg twice daily, consider initiating dronabinol capsules at 2.5 mg once daily one hour before dinner or at bedtime to reduce the risk of central nervous system (CNS) symptoms [see Use in Specific Populations (8.5)]. Dronabinol capsules are indicated in adults for the treatment of: • anorexia associated with weight loss in patients with Acquired Immune Deficiency Syndrome (AIDS). In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy Megestrol acetate is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function.

Comparison of Medications:

• Dronabinol is indicated for anorexia associated with weight loss in patients with AIDS, and has specific dosage recommendations for elderly patients.
• Megace (megestrol acetate) does not have specific indications for anorexia associated with weight loss in elderly patients, but has warnings for use in this population due to potential renal toxicity.

Key Considerations:

• Dronabinol has a more specific indication for weight loss in patients with AIDS.
• Megestrol acetate has a warning for use in elderly patients due to potential renal toxicity.
• Dose selection for elderly patients should be cautious for both medications.

Based on the information provided, dronabinol may be a more suitable option for an elderly patient with weight loss, due to its specific indication for this condition and dosage recommendations for elderly patients 2. However, the decision should be made on a case-by-case basis, taking into account the individual patient's needs and medical history.

From the Research

Comparison of Megace and Dronabinol for Weight Loss in Elderly Patients

• Both Megace (megestrol acetate) and dronabinol are used as appetite stimulants for weight loss in elderly patients 3, 4, 5.
• Megestrol acetate has been shown to be effective for appetite stimulation and weight gain in some settings, but its applicability to elderly individuals is unclear, and adverse events such as deep vein thrombosis have been reported 3, 6.
• Dronabinol is also used for appetite stimulation, and its use is recommended for most anorectic patients, with a low initial dose of 2.5 mg in the evening, increasing to 5 mg per day if no improvement is seen after 2-4 weeks 5.
• A systematic review of megestrol acetate for cachexia-anorexia syndrome found that it increased weight gain, but did not improve quality of life, and was associated with more adverse events compared to placebo 7.
• There is no direct comparison between Megace and dronabinol in the provided studies, but both medications have been used for appetite stimulation and weight gain in elderly patients.

Adverse Events and Considerations

• Megestrol acetate has been associated with adverse events such as deep vein thrombosis, particularly in geriatric patients with impaired mobility 6.
• Dronabinol can be continued indefinitely, but its use should be monitored for adverse events such as psychoactive effects 5.
• The use of appetite stimulants such as megestrol acetate and dronabinol should be thoroughly evaluated on an individual basis, taking into account the patient's medical history, mobility, and potential for adverse events 3, 4, 5.

Pharmacological Treatment Options

• Other pharmacological treatment options for weight loss in elderly patients include mirtazapine, which has been used for appetite stimulation and weight gain, particularly in patients with depression and anorexia 3, 5.
• Anabolic agents such as oxandrolone may be reserved for patients with profound cachexia, and testosterone replacement therapy may be considered for older men with low bioavailable testosterone levels 5.