Antineutrophil cytoplasmic antibody-positive vasculitis in a patient with graves disease: cross-reaction between propylthiouracil and methimazole.

Abstract

OBJECTIVE:

To alert clinicians about the risk of vasculitis and cross-reactivity of antithyroid medication.

METHODS:

We describe the clinical course and medical management of the study patient.

RESULTS:

A 25-year-old woman with hyperthyroidism developed antineutrophil cytoplasmic antibody-positive vasculitis after 15 months of propylthiouracil therapy. Her condition improved when propylthiouracil was withdrawn, but recurred when she was prescribed methimazole. Propylthiouracil and methimazole are commonly used antithyroid medications, and propylthiouracil is a well-recognized cause of drug-induced vasculitis. Cross-reactivity between the 2 drugs is likely, but it has not been reported previously with regard to vasculitis. Many patients with propylthiouracil-induced vasculitis have been switched to methimazole.

CONCLUSIONS:

Awareness of this rare, but potentially serious, adverse drug reaction is important because prompt discontinuation of medication is essential. Cross-reactivity between propylthiouracil and methimazole must be considered when selecting alternative therapies.

• Authors: Khulood Ahmed, Sneha Rao, Vinaya Simha
• Journal: Endocrine practice : official journal of the American College of Endocrinology and the American Association of Clinical Endocrinologists (Endocr Pract) 2010 May-Jun Vol. 16 Issue 3 Pg. 449-51 ISSN: 1934-2403 [Electronic] United States
• PMID: 20061292 (Publication Type: Case Reports, Journal Article)

Chemical References

• Antibodies, Antineutrophil Cytoplasmic
• Antithyroid Agents
• Methimazole
• Propylthiouracil

Topics

• Adult
• Antibodies, Antineutrophil Cytoplasmic (metabolism)
• Antithyroid Agents (adverse effects, therapeutic use)
• Drug Interactions
• Female
• Graves Disease (complications, metabolism)
• Humans
• Methimazole (adverse effects, therapeutic use)
• Propylthiouracil (adverse effects, therapeutic use)
• Vasculitis (drug therapy, metabolism)