Nifedipine therapy during pregnancy can have two purposes: lowering blood pressure (and preventing eclampsia) and postponing delivery.
Nifedipine blocks the entry of Ca2+ into myometrial cells via voltage-gated Ca2+ channels, blocks voltage-dependent Ca2+channels and reduces intracellular Ca2+ #e4eaff;"> levels. All these actions result in uterine smooth muscle relaxation.
Various studies have shown that nifedipine therapy during the second and third trimesters lowers maternal blood pressure without affecting fetal heart rate or fetal blood pressure. Nifedipine's efficacy and low toxicity are expected to make it a much-used agent during pregnancy. Based on pharmacokinetic studies demonstrating higher rates of clearance and a shorter half-life for nifedipine in pre-eclampsia, researchers suggest a dosing interval of 3 to 4 hours when rapid-release nifedipine is used during gestation.
Nifedipine safely and effectively postpones delivery without adverse effects for the fetus and minor temporary side effects for the mother. The drug has fewer side effects compared to α2-agonists in delaying delivery.
Check the cardiology section for more information on calcium antagonists.