Ritodrine-induced erythematous papular eruption in 14 pregnant women

Ritodrine hydrochloride, a β2-adrenergic agonist, has been used for the treatment of pre-term labor as a relatively safe agent, although tolerable side-effects have been occasionally reported.

The purpose of this study was to assess our clinical experience of skin eruptions caused by ritodrine.

Fourteen pregnant women with pruritic skin eruptions associated with the administration of ritodrine for pre-term labor were examined in Saitama Medical Center Hospital between 2005 and 2008.

Patients included both primigravidas and multigravidas. Their mean age was 33.7 years (range: 27-41 years). Almost all subjects were in the third trimester of pregnancy. Skin eruptions occurred 7-27 days (mean: 14.9 days) after the start of intravenous or oral ritodrine. In eight patients, the eruption occurred after an increase in the dose of the drug. The reaction was characterized by a pruritic, erythematous, papular eruption, mainly distributed on the abdomen and upper extremities. Lymphocyte transformation tests for ritodrine were positive in five of the eight patients.

Ritodrine-induced, erythematous, papular eruption probably occurs more frequently than has been previously estimated. An immunologic mechanism may play a role in the development of this eruption caused by ritodrine, although the reaction is somewhat dependent on the dose.