The question concerns the risk for fetal damage with salmeterol treatment. A 24-year-old pregnant w

Fråga: The question concerns the risk for fetal damage with salmeterol treatment. A 24-year-old pregnant woman (week 8) with asthma has been treated with inhalation therapy since March 1992. Her treatment is Serevent (salmeterol) 50 ug 2x2 and Ventoline Diskhaler 0.4 mg as needed and Pulmicort (budesonide) 400 ug 1-3 x2 and theophylline rectally when needed. The asthma is adequately controlled with this medication. Does the salmeterol treatment increase the risk for the fetus?

Sammanfattning: Although one should be cautious when using a new drug during pregnancy, there is no evidence that beta-stimulants cause fetal damage, nor is there any indication from animal experiments or the limited experience of treatment of pregnant women that the use of this drug during pregnancy might be harmful. Treatment with an inhaled long-acting sympathomimetic might also be beneficial for the fetus by possibly avoiding systemic treatment with beta-stimulants. Such an advantage may justify the use of a new drug in this situation.

Svar: Salmeterol is a new long-acting inhaled beta-2-adrenoceptor agonist for treatment of asthma. Beta-2-agonists are generally not believed to cause fetal damage but may affect the contractility of the uterus and may delay or postpone delivery. Beta-stimulants should therefore be used with some caution in the later stages of pregnancy (1).

Inhalation therapy usually causes lower systemic and fetal levels of drugs than systemic treatment and is therefore preferable.

Salmeterol is a new beta-stimulant and experience in humans in general and pregnant women in particular is limited. However, animal experiments have not shown any increased risks for fetal damage. The drug is therefore classified as B1 in FASS (2). Salmeterol does not show any mutagenicity and is similar to other beta-agonists in studies of carcinogenicity (3).

The kinetics and metabolism of salmeterol has not been studied extensively but salmeterol is metabolised by hydroxylation and it has at least one active metabolite. Steady-state levels of salmeterol are achieved within approximately one week (4).

In the clinical trials pregnancy was not considered a contraindication for salmeterol treatment and no damage to the fetuses have been reported (5). We have done a Medline search, looked into the Swedish Adverse Drug Reactions Advisory Committee (SADRAC) files and into the WHO register for side-effects. We have found no reports of fetal damage by salmeterol.