<prompt> Drug not useful in emergency condition in pregnancy:NifedipineLabetalolRitodrinePhenobarbitone  <response>: Ref: Katzung, 14th ed. pg. 203-204; KDT, pg. 323 Nifedipine is a calcium channel blocker which is used as an alternative drug for premature labor. Influx of calcium ions plays an important role in uterine contractions. CCBs reduce tone of myometrium and oppose contractions. These drugs, especially Nifedipine can postpone labor only if started early enough. In emergency situation, Ritodrine b2 selective agonist is considered as the drug of choice to suppress preterm labor. Drug of choice for hypertension in pregnancy- LABETALOL Drug of choice for epilepsy in pregnancy- Lamotrigine DOC for status eclampticus in pregnancy - phenobarbitone 