Which of the following is a Tocolytic agent?

ANSWER: (B) RitodrineREF: Danforth's Obstetrics and Gynecology 10th Edition page 175-178,http://en.wikipedia.org/ wiki/TocolyticIndirect repeat from June 2008See APPENDIX-64 for "TOCOLYTIC AGENTS" APPENDIX - 64Tocolytic Agents:DrugMechanismDescriptionContraindicationsTerbutalineb2-agonistIs often the drug given first, especially if there is only low risk of preterm birthCardiac arrhythmiasRitodrineb2-agonistThe only FDA approved tocolyticPoorly controlled thyroid disease and diabetesFenoterolb2-agonist diabetesSalbutamolb2-agonist diabetesNifedipineCCBsIs one of the most commonly used tocolytic agentsCardiac disease. It should not be used concomitantly with magnesium sulphateAtosibanoxytocinantagonist IndomethacinNSAIDs late pregnancy (ductus arteriosus), significant renal or hepatic impairmentSulindacNSAIDs Coagulation disorders or thrombocytopenia, non-steroidal antiinflammatory drug (NSAID)-sensitive asthma, other sensitivity to NSAIDsIV Magnesium sulfatemyosin light chain inhibitorShown to be ineffective. Has been recommended for women at high risk. However, meta-analyses have failed to support it as a tocolytic agentmyasthenia gravisEthyl alcohol?Shown to be ineffective. Was frequently prescribed as a tocolytic in the mid-20th century, but later double-blind studies found it was not effective