From the Guidelines
Megestrol acetate (Megace) is indicated for the treatment of anorexia, cachexia, or significant weight loss in patients with cancer or AIDS, with a typical starting dose of 400-800 mg daily for poor appetite. For poor appetite, the dose can be taken as a single dose or divided into multiple doses, with the oral tablet form usually dosed at 160-800 mg daily 1. Treatment should continue for at least 2-3 months to adequately assess effectiveness, with regular monitoring of weight and appetite improvement. Dose adjustments may be needed based on response and tolerability. Megace works by stimulating appetite through multiple mechanisms, including anti-inflammatory effects and modulation of neuropeptide Y and calcium channels involved in appetite regulation.
Some key points to consider when using Megace for poor appetite include:
- Common side effects include edema, thromboembolism, adrenal suppression, and hyperglycemia 1
- Caution is advised in patients with diabetes, history of thromboembolism, or heart failure 1
- Blood glucose levels should be monitored, especially in diabetic patients 1
- The medication may take 1-3 weeks to show appetite improvement, with weight gain typically following 1
- Higher doses of megestrol acetate were associated with greater improvement in weight than lower doses, but also with increased risks of adverse events such as thromboembolic events and edema 1
It is also important to note that combination therapy approaches may yield the best possible outcomes for patients with cancer cachexia, and that other appetite stimulants such as dexamethasone and olanzapine may also be considered 1. However, the use of megestrol acetate is supported by the most recent and highest quality evidence, including a 2020 guideline from the American Society of Clinical Oncology 1.
From the Research
Indication of Megace for Poor Appetite
- Megestrol acetate, also known as Megace, is used to stimulate appetite and improve weight gain in patients with cancer-related anorexia/cachexia 2, 3, 4, 5.
- It is also used to treat malnutrition-inflammation complex syndrome and anorexia in maintenance dialysis patients 2.
- Megace has been shown to increase appetite and food intake, and mitigate inflammation in cachectic AIDS and cancer patients, leading to weight gain 2, 4.
Dose of Megace for Poor Appetite
- The conventional dose of Megace is 800 mg/day, but a lower dose of 400 mg/day has been shown to be effective in improving appetite and weight gain in maintenance dialysis patients with minimal side effects 2.
- A systematic review and meta-analysis found that high-dose Megace (>320 mg/day) tended to result in weight loss rather than weight gain, while low-dose Megace (≤320 mg/day) had a more favorable effect on weight change 3.
- Other studies have used doses of 800 mg/day of Megace to stimulate appetite and improve weight gain in cancer patients 4, 5.
Side Effects and Considerations
- Megace can cause side effects such as Cushing's syndrome, new-onset diabetes, and suppression of plasma ACTH and cortisol levels, particularly at high doses or with prolonged treatment 6.
- It can also cause adrenal insufficiency, and recognizing the glucocorticoid-like activity of Megace is important for the diagnosis of sub-clinical adrenal insufficiency 6.
- The risk of thromboembolism is also increased with Megace, especially at higher doses 3.