Methimazole

Oral health effects

• Agranulocytosis risk (oral ulceration/infection) & dysgeusia

  Rarely causes agranulocytosis: unexplained oral ulceration, sore throat, or infection can be a presenting sign. Taste alteration also reported.

  Clinical management: Investigate unexplained oral ulceration/sore throat; coordinate urgent CBC with the physician.

• Bleeding tendency (hypoprothrombinemia)

  Methimazole may cause hypoprothrombinemia and bleeding; the label advises monitoring prothrombin time, especially before surgical procedures. Thrombocytopenia can also occur as part of drug-induced marrow suppression.

  Clinical management: Ask about unusual bruising or gum bleeding; before extractions or periodontal surgery, confirm with the physician that recent coagulation tests/blood counts are acceptable and use local hemostatic measures.

• Salivary gland swelling (sialadenopathy)

  Sialadenopathy is listed among the minor adverse reactions of methimazole (label).

  Clinical management: Note new parotid/submandibular swelling and refer to the prescriber to assess, particularly if accompanied by fever or sore throat (exclude agranulocytosis-related infection).