Can 7 months of methadone treatment for heroin addiction cause a large weight gain? eating reasonably. swelling in hands & feet.

Looks like it did.: Methadone in and of itself does not usually cause weight gain and certainly not a large gain. However, the preceding heroin may have caused significant weight loss which makes it appear that Methadone caused weight gain. Swelling in hands and feet is concerning for lots of other things including malnutrition, chronic liver, kidney and heart disease in addition to a host of inflammatory disorders.

I see it sometimes: Opiods interfere with appetite and metabolism controls in the hypothalamus. In fact, opioid blockers lead to weight loss. Weight gain is more pronounced when other meds are also used. I have the swelling as well but don't understand the mechanism