Table 2.

Adverse effects of antithyroid drugs.

Adverse effects that require the immediate cessation of thionamide treatment: 1) Agranulocytosis (<500/µL; 0.2–0.5% treated), aplastic anemia (even rarer) 2) Acute hepatitis (sporadic; mainly after PTU), cholestatic jaundice (after thiamazole) 3) Vasculitis with antibodies to neutrophil cytoplasm (ANCA) and lupus-like syndrome. 4) Acute pancreatitis

Adverse effects that do not require the immediate cessation of thionamide treatment (a dose reduction or change of medication may be sufficient): 1) Pruritus, urticaria (1–5%), sometimes very severe skin symptoms – they can be controlled with antihistamines or by changing the antithyroid drug 2) Muscle and joint pain (in arthritis, found in 1–5% of cases, most often it is necessary to stop treatment) 3) Taste disorders 4) Nausea and vomiting (depending on the dose, it is worth using the drug in divided doses) 5) Increase in serum aminotransferase activity (up to 30% of patients treated in the past with PTU; a mild increase does not necessarily lead to treatment discontinuation) 6) Transient granulocytopaenia (1–5%) or thrombocytopaenia (<1%) may disappear after the drug dose has been reduced:    a) 1500–1000/μL – more frequent controls are recommended, consider a dose reduction of ATD    b) 1000–500/μL – reduce the dose or consider stopping the drug.