Which of thioamide group of drugs is associated with positive Anti neutrophilic Cytoplasmic antibodies (ANCAs)?

1. carbimazole
2. Methimazole
3. propylthiouracil
4. thiocyanate

ANSWER: Propylthiouracil

GG 13E/P 798

• Antineutrophilic cytoplasmic antibodies (ANCAs) have been reported to occur in about 50% of patients receiving propylthiouracil
• Most common  ADR is mild urticarial papular rash
• Agranulocytosis is the most serious reaction
  • seen  in the first few weeks or months of therapy but sometimes later