A rapid desensitization protocol in a case of drotaverine-induced serum sickness-like reaction in a pregnant woman: A case report.

Drotaverine is an antispasmodic drug used to treat gastrointestinal and genitourinary smooth muscle spasms. There are very few hypersensitivity reactions reported. Serum sickness-like disease is an immune-complex-mediated hypersensitivity reaction that presents with some typical features that include rash, fever and articular impairment sometimes associated with liver and renal dysfunctions, beginning 1-2 weeks after exposure to a culprit drug. Diagnosis is a clinical one, made usually on the basis of knowledge obtained by medical history and physical examination. Desensitization usually is recommended for type I reaction, but may be a solution for this type of immunological reaction when other therapeutic alternatives are ineffective or do not exist. We report the case of a 29-year-old pregnant female who developed serum sickness-like reaction after 5 days of daily drotaverine oral administration. The patient required antispasmodic treatment, with this drug, having a pregnancy with an imminent risk of abortion and the other therapeutic alternatives being ineffective. She underwent a rapid 7-step oral drotaverine desensitization protocol without recurrence of serum sickness-like reaction. To our knowledge, this is the first case report of desensitization to drotaverine, previously involved in a serum sickness-like reaction.