[Use of calcium channel blockers (CCB) for tocolysis in France and abroad]

Calcium channel blockers (CCB) are routinely off-label used for tocolysis. The purpose of this study is to establish an inventory of the use of CCB for tocolysis in France and abroad.Four complementary approaches were performed: (i) a literature review of clinical practice and guidelines of scientific societies; (ii) a national declarative practice survey among French tertiary care centers; (iii) a regional declarative practice survey among all maternities of the Midi-Pyrénées Perinatal Network (MATERMIP); (iv) an evaluation of outpatient tocolysis prescription, analyzing the departmental database EFEMERIS in order to examine drug prescribing during pregnancy.CCB appear to be currently used as first-line, initial tocolysis, in the majority of French maternity hospitals (82.5% of tertiary care centers). Oral Nifedipine is the predominant regimen (86%). CCB utilization rates appear higher than those reported in 2005 in the EVAPRIMA study. Beta-agonists appear rarely prescribed in 1st line (poor maternal tolerance) and even abandoned by many institutions (75% of tertiary care centers). Using a maintenance tocolysis (usually by long-acting CCB) seems to vary depending on the hospitals. It would be prescribed in more than 50% of cases (and probably more in type 1 or 2 hospitals), despite the lack of demonstrated benefit. Furthermore, we can estimate that about 1.5 to 2% of outpatient pregnant women receive a prescription of Nifedipine LP in France.CCB (especially Nifedipine) are widely used in the treatment of threatened preterm labor in France, regardless of the type of hospital. The terms of off-label prescribing are not met.