Hi, Methadone is a synthetic opioid medication that is primarily used for the treatment of pain and the management of opioid addiction. While Methadone is generally considered safe and effective when used as directed under medical supervision, it can cause a range of side effects in some people. Confusion, forgetfulness, and hand tremors are known side effects of Methadone. Methadone can also cause dizziness, drowsiness, nausea, vomiting, constipation, and difficulty breathing. It is important for individuals taking Methadone to follow their doctor s instructions carefully and not to adjust their dosage without medical supervision. Methadone can interact with other medications, such as some antidepressants and blood pressure medications, which may increase the risk of side effects. It is important for individuals taking Methadone to inform their doctor of all medications they are taking, including over-the-counter drugs and supplements, to avoid potential interactions. Sleep apnea can also be a serious condition that requires medical attention. Individuals with sleep apnea need to seek medical evaluation and follow their doctor s recommended treatment plan. If your friend s son is concerned that his mother is experiencing serious health issues, she needs to seek medical attention promptly. The symptoms you have described may be related to Methadone use, but they could also be related to other health conditions or interactions with other medications. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Priyanka, General & Family Physician