Butylscopolamine bromide— also known as hyoscine butylbromide — is an anticholinergic antispasmodic agent used to treat pain and discomfort caused by abdominal cramps. Although it is widely used, reports of immediate hypersensitivity reactions after butylscopolamine administration are unusual.
We present a case of a 52 years old male patient, without history of adverse reactions to drugs, who suffered an episode of immediate generalized urticaria and facial angioedema after administration of intravenous butylscopolamine bromide. The patient was treated in the emergency department, receiving intramuscular adrenaline and intravenous corticosteroids, with good response and clinical improvement. Subsequently, the patient was referred to our outpatient clinic for evaluation of a possible butylscopolamine allergy.
We conducted an allergy study, consisting in skin tests with the drug involved (butylscopolamine bromide 20 mg/ml). Skin prick tests with butylscopolamine were negative. Intradermal tests with progressive concentrations of butylscopolamine were positive at 1/100 and 1/10 dilutions. All tests were negative in 10 control patients. Oral provocation with the drug was dismissed.
We present a rare case of urticaria and angioedema due to butylscopolamine bromide. Positive intradermal tests with this drug suggest an allergic IgE-mediated mechanism.