 Many substances can also induce, inhibit or compete with these enzymes further affecting (sometimes dangerously) methadone half-life.A longer half-life frequently allows for administration only once a day in Opioid detoxification and maintenance programs.People who metabolize methadone rapidly, on the other hand, may require twice daily dosing to obtain sufficient symptom alleviation while avoiding excessive peaks and troughs in their blood concentrations and associated effects.