<prompt> Single most effective drug used for prophylaxis of gestational trophobalstic diseases:MethotrexateCytosine arabinosideL-AsparaginaseProcarbazine  <response>: Ans: a Methotrexate Ref: Shaw, 13th ed, p. 258Most effective chemotherapeutic agent in GTD is folic acid inhibitor methotrexate. It interfers with nucleic acid formation and mitosis in maliganant cells and thereby arr ests the growth.Indication for methotrexate in H-molea High level of HCG 4 weeks post evacuationSerum 20,000 IUltrUrine 30,000 IU24hrsb Persistent uterine haemorrhagec Progressively rising HCG level at any time post evacuationd Any detectable HCG level not showing tendency to extinction 4-6 months post evacuation.e Evidence of brain, renal, hepatic, GIT or pulmonary metastasis at any level of HCGSide effects1. Ulcerative stomatitis and gastric haemorrhage2. Skin reaction and alopecia3. Bone marrow depression -anaemia, leukopenia, agranulocytosis4. Hepatic and renal damageFolic acid rescue regime-Methotrexate and folinic acid administered on alternate days to reduce toxicityMAC regime is used for the treatment of choriocarcinoma.Commonly used regimes are:MAC regimeEMACO regimeMethotrexateActinomycinDChlorambucilEtoposideMethotrexateActinomycinDCyclophosphamideVincristine oncovinMMA regimeMethotrexateActinomycin DAdriamycin 