is taken under medical supervision, long-term maintenance causes no adverse effects to the heart, lungs, liver, kidneys, bones, blood, brain, or other vital body organs. <span style = 'background-color: #dae8f4'>methadone</span>
produces no serious side effects
, although some patients experience minor symptoms such as constipation, water retention, drowsiness, skin rash
, excessive sweating, and changes in libido. Once methadone
dosage is adjusted and stabilized or tolerance increases, these symptoms usually subside.