[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.