Why do you ask this question,call your Doctor oer pharmacistand ask them,id like to answer this question because I know the answer,butIthink you should contact Pharmacist and get all the side affects,and possible side affects list.Also,ask question (s).Also, you can look it up online.
That is an excellent question.
Methadone is an opiate, and all opiates are generic vasodilators - that is to say they cause the interior od blood vessels to widen, increasing body capacitance, and lowering blood pressure. They also have an analgesic effect, and cause slowing of peristalsis, or movement of the feces through the intestines.
That being said there is no reason to connect methadone use with kidney failure.