[Which tocolytics should be used in 2001?].

Abstract

Beta-mimetics are the gold standard tocolytic treatment but raise several problems. Despite their recognized efficacy in prolonging pregnancy, the neonatal benefit remains to be proven. There are several contraindications and frequent adverse effects, with a risk of fatal maternal accidents. The lack of reliable criteria for the prediction of preterm birth leads to giving unnecessary treatments to two-thirds of the patients. In this context, obstetrical practices have tended to prefer tocolytics which, with the same efficacy, would have fewer side effects than beta-mimetics and which would not raise a risk of severe complications. Calcium-channel blockers belonging to the dihydropyridin family and ocytocin antagonists would appear to meet the new requirements. In randomized trials versus beta-mimetics, they have been found to have a comparable effect in prolonging pregnancy by 48 hours. Tolerance is better than with beta-mimetics and treatment interruption due to side effects can be avoided. Finally, a meta-analysis of trials comparing calcium inhibitors versus beta-mimetics demonstrated a decrease in respiratory distress syndrome in the neonates and a reduction in the number of transfers to neonatal intensive care. The data accumulated on these new compounds would appear to suggest that they should be used as the first line treatment and not as an alternative to beta-mimetics. Other compounds including NO donors and cyclo-oxygenase 2 inhibitors are under evaluation.