Prescribing of sulfasalazine, azathioprine and methotrexate round pregnancy--a descriptive study

Continuation or discontinuation of drugs during pregnancy in chronic diseases is an issue of concern. Information on prescribing of disease modifying anti-rheumatic drugs (DMARDs) during pregnancy is scarce. In this study, we report prescribing patterns round pregnancy of sulfasalazine (SSZ), azathioprine (AZA), methotrexate (MTX) and co-medications among women to whom one of these DMARDs were prescribed before pregnancy.

The pregnancy-interaction database (IADB.nl, 1994-2004), containing pharmacy dispensing data from Northern- Netherlands, was used. Women to whom SSZ (N = 13), AZA (N = 10) or MTX (N = 6) was prescribed before their first pregnancy were identified and described in detail.

AZA and SSZ are continued during pregnancy by 60% and 38% of the women, respectively, MTX was stopped before pregnancy. Among women receiving SSZ (N = 13) as their initial DMARD, anti-inflammatory and anti-rheumatic drugs (69%) and analgesics (45%) were the most commonly prescribed co-medications. Among women receiving AZA (N = 8) as their initial DMARD, corticosteroids for systemic use (100%) and intestinal anti-inflammatory agents (88%) were the most commonly prescribed co-medications. All women receiving intestinal anti-inflammatory drugs before pregnancy continued this during pregnancy, in contrast to other co-medications which were mainly discontinued.

Our study showed that DMARDs and co-medication are received before, during and after pregnancy, although no specific prescription patterns were found. Administrative databases, such as the pregnancy-IADB.nl, are useful in describing drug-prescribing patterns for better understanding of drug prescribing around pregnancy in daily practice. Based on these data, we conclude that prescribing of DMARDs and related co-medication is based on the individual patient.