Additional studies were conducted in 1975 and 1978, followed by others thereafter. However, results of MGA therapy for prostate cancer have been "disappointing", and the medication has not been approved for the treatment of prostate cancer in the United States or elsewhere.Clinical studies of very high dosages of MGA for breast cancer conducted in the 1980s observed markedly increased appetite and weight gain in treated patients despite them having advanced cancer. This led to potential interest in MGA as an appetite stimulant, and in 1986, a paper was published proposing the study and potential use of MGA in cachexia. MGA was subsequently studied for this indication and, following completion of phase III clinical trials, was approved as an oral suspension for the treatment of anorexia–cachexia syndrome due to cancer and other chronic conditions such as HIV/AIDS in the United States in 1993. Thereafter, the branded product, Megace ES, has been heavily promoted by its maker, Par Pharmaceutical, for treatment of unintentional weight loss in elderly patients, especially those living in long-term care facilities. In March 2013, Par settled a $45 million federal and multi-state criminal and civil lawsuit in which the company was accused of promoting the branded version of MGA, over the generic version, for use in treating non-AIDS-related geriatric wasting. This use was not approved as safe and effective by the Food and Drug Administration (FDA), and not covered by federal health care programs.
Many opponents believe that replacement drugs only substitute one addiction with another, and that methadone can be manipulated and exploited in some cases. Long-term usage has the ability to cause brain changes. Methadone causes changes in thought, cognitive performance, and memory by influencing nerve cells in the brain. An initial review is performed during alcohol therapy. The person will be evaluated and interviewed during this evaluation, and then the treatment team will then devise the optimal treatment plan for that individual. Methadone 
Methadone is a drug used for both opioid overuse treatment and for chronic pain, it is known as a full opioid agonist. Methadone is the most common prescribed out of all the medications used for addiction; this is due to the fact that it has more advantages and less disadvantages than the other medications. Due to methadones longer half life, it is much more challenging to prescribe dosage amounts compared to others. The long half life has good benefits, one of these benefits being the fact that if a dose is missed in the 24 hours of the last, the patient will not typically struggle with withdrawal symptoms quite yet. Methadone can be found in a couple different forms: tablet, oral solution, or an injection. The first time this medication was put to use was during World War II, it was a safer alternative to morphine. Buprenorphine
Buprenorphine is a partial opioid receptor agonist. Unlike methadone and other full opioid receptor agonists, buprenorphine is less likely to cause respiratory depression due to its ceiling effect.