No effective vaccine available to prevent HIV. The practice is low daily dose for fear of ADR's and variable pharmacology of CYP2B6,CYP2D6 and ??-opiate receptor gene. This causes high failure rates. Informed Methadone therapy with Pharmacogenetics and TDM. Customized pharmacogenetic testing combined with ELISA monitoring of methadone levels.Patients screened for genetic polymorphism of CYP2B6 and ??-opiate receptor. Dose of methadone determined based on polymorphism.Blood obtained for plasma methadone. Methadone dose adjusted. The results may improved compliance and retention and reduces risks for HIV.