Carbimazole Oral Solution – Abbreviated Prescribing Information

Abbreviated Prescribing Information: Carbimazole Rosemont 2.5mg/ml Oral Solution. Consult Summary of Product Characteristics before prescribing. Presentation: An oral solution. Each 1 mL containing 2.5mg of carbimazole. Therapeutic Indications: Carbimazole is an anti-thyroid agent indicated for hyperthyroidism, preparation for thyroidectomy in hyperthyroidism and therapy prior to and post radio-iodine treatment. Posology and Method of Administration: Carbimazole should be administered only after lab-confirmed hyperthyroidism and should not be used where peppermint oil dose exceeds 1.62 mg/kg/day (equivalent to 7.5 mL/day for children ≥3 years, 38 mL/day for adults). Carbimazole 2.5mg/ml should be administered orally with a glass of water. Adult population: The initial dose is in the range 20 mg to 60 mg (8 ml to 24 ml), taken as two to three divided doses. The dose should be titrated against thyroid function until the patient is euthyroid. Subsequent therapy may then be administered either as Maintenance regimen or Blocking-replacement regimen where therapy should be continued for at least 6 months and up to 18 months. Maintenance regimen: The final dose is in the range of 5 mg to 15 mg (2mL to 6 mL) per day, with serial thyroid monitoring and appropriate dosage modification to maintain a euthyroid state. Blocking-replacement regimen: The dosage is maintained in the range of 20 mg to 60 mg (8mL to 24 ml) per day along with concomitant administration of L-thyroxine at 50 mcg to 150 mcg per day to prevent hypothyroidism. Elderly population: No special dosage is needed, but caution is advised due to increased risk of fatal neutrophil dyscrasia in patients aged 65 and above. Paediatric population: The initial daily dose in children and adolescents (3 years to 17 years) is 15 mg (6 ml) per day adjusted as per response. The safety and efficacy of carbimazole in children aged 2 years and below has not been evaluated, therefore not recommended. Contra-indications: Hypersensitivity to the active substance or to any of the excipients. Carbimazole is contraindicated in serious, pre-existing haematological conditions, severe hepatic insufficiency and in patients with a history of acute pancreatitis after administration of carbimazole or its active metabolite thiamazole. Special Warnings and Precautions for use: Bone marrow depression including neutropenia, eosinophilia and leucopenia. Fatalities with carbimazole-induced agranulocytosis, pancytopenia/aplastic anaemia, isolated thrombocytopenia and haemolytic anaemia. Patients must be warned to stop treatment and seek medical help if symptoms like sore throat, bruising, bleeding, ulcers, fever, or malaise occur; immediate white blood cell testing is advised, especially if infection is suspected. Carbimazole should be stopped, and liver function tests must be performed immediately if signs of hepatic disorder (upper abdominal pain, anorexia, pruritus) appear. Early withdrawal of the drug will increase the chance of complete recovery. Carbimazole should be used with caution in patients with mild-moderate hepatic insufficiency. Treatment should be discontinued if abnormal liver function is discovered. Carbimazole should be stopped temporarily at the time of administration of radioiodine. Patients unable to comply with the instructions for use or who cannot be monitored regularly should not be treated with carbimazole. Regular full blood count checks should be carried out in patients who may be confused or have a poor memory. Precaution should be taken in patients with intrathoracic goitre. The use of carbimazole in non-pregnant women of childbearing potential should be based on individual risk/benefit assessment. If used during pregnancy, the lowest effective carbimazole dose without added thyroid hormones should be given. Close maternal, foetal and neonatal monitoring is warranted. Any warning from the MC, CHM CSM or MHRA: No. Black Triangle notice: Not applicable. A list of most frequently occurring reactions and serious adverse reactions is listed below: Most frequently occurring reactions: nausea, headache, arthralgia, mild gastric distress,

skin rashes and pruritus. Serious adverse reactions: Bone marrow depression including neutropenia, eosinophilia, leucopenia, agranulocytosis, pancytopenia/aplastic anaemia, thrombocytopenia, haemolytic anaemia, generalised lymphadenopathy, angioedema, multi-system hypersensitivity reactions such as cutaneous vasculitis, liver, lung and renal effects, insulin autoimmune syndrome, neuritis, polyneuropathy, bleeding, acute salivary gland swelling, acute pancreatitis, hepatitis, cholestatic hepatitis, cholestatic jaundice, loss of sense of taste, hair loss, urticaria, severe cutaneous hypersensitivity reactions including Stevens-Johnson syndrome, generalized dermatitis and myopathy. Refer to the SmPC for full details of adverse reactions. Pack Size and NHS Price: 150ml – £266.20. Marketing Authorisation Number: PL 00427/0291. Marketing Authorisation Holder: Rosemont Pharmaceuticals Ltd, Rosemont House, Yorkdale Industrial Park, Braithwaite Street, Leeds, LS11 9XE, UK. Legal Category: Prescription only medicine. Date of Preparation: August 2025