If you have cancer or chronic wasting diseases such as HIV, you may lose weight, even when you’re trying not to, leading to a condition called cachexia. Elderly people without much appetite can also lose excessive amounts of weight due to appetite loss. Weight loss under these conditions can increase mortality rates. Megestrol acetate, a synthetic progestin hormonal treatment, can significantly increase appetite, resulting in needed weight gain.
Megestrol acetate has hormonal effects that interfere with estrogen and other hormones. It’s not clear why this drug stimulates the appetite. Because of its hormonal interaction, hormone-dependent tumors may shrink in response to megestrol actetate. You can take this medication in liquid or tablet form; the normal dose is between 160 and 800 mg per day, with no additional benefit seen in doses above 800 mg, according to Mike Salacz, M.D. of the Medical College of Wisconsin.
Megestrol acetate is equally as effective as dexamethasone and better than dronabinol in increasing appetite, according to Salacz. The weight gain that occurs consists mostly of an increase in fatty tissue rather than lean muscle. Fluid retention does not account for the weight gain with this drug. In cancer patients, only between 20 and 30 percent have a positive response, defined as weight gain of more than 5 percent, after six to eight weeks of treatment, Salacz reports.
Outside of weight gain, side effects that occur in between 10 and 29 percent of people include edema, or swelling, of the hands and feet and breakthrough bleeding in women. Diarrhea occurs in 15 percent; 14 percent of men taking the drug experience impotence and headache occurs in 10 percent. You may also have increased sun sensitivity. Serious risks of this drug include an increased chance of developing blood clots. Report any calf pain, redness or swelling, or shortness of breath to your doctor immediately. Megestrol acetate can also increase blood glucose levels. Do not take this drug if there is a chance of becoming pregnant since it can increase birth defects.
Whether an increase of fat as opposed to muscle tissue has any benefit in treating chronic disorders such as cancer is not clear, according to an editorial published in the February 2007 issue of “The Journal of Clinical Endocrinology & Metabolism.” An increase in appetite can have a palliative effect, however, in end-stage cancer treatment even if no other benefit occurs.