Carbimazole Flashcards
what is carbimazole?
imidazole antithyroid agent.
This is metabolised to methimazole which is responsible for the antithyroid activity
What class of drugs does carbimazole belong to?
antithyroid agents
What are other examples of drugs in the same class as carbimazole?
iodine
potassium perchlorate (for hyper)
propylthiouracil (hyper)
levothyroxine
What is carbimazole indicated for?
hyperthyroidism and thyrotoxicosis
What is the mechanism of action of carbimazole?
- In the active form, carbimazole prevents thyroid peroxidase enzyme from forming T3 and T4 hormones
- decreases the uptake and concentration of inorganic iodine by thyroid.
- reduces di-iodotyrosine and thyroxine formation
what is the role of carbimazole in hyperthyroidism?
-commonly used drug
given 15-40mg daily with higher doses prescribed under specialist supervision only
What are the relevant PD/PK parameters associated with carbimazole use?
- half life 6.4 hours,
- 85% protein bound
What are the precautions associated with carbimazole use?
- monitor for evidence of neutropenia and agranulocytosis
- use with caution with hepatic imapirment
- pregnancy class C,
What are the contraindications with carbimazole use?
severe blood disorders
What are the adverse effects with carbimazole use?
nausea, mild GI disturbances, taste disturbance, headache, fever, malaise, rash, pruirtus, arthralgia
What are the relevant drug interactions with carbimazole use?
antithyroid drugs should be withdrawn prior to metyrapone test.
may need higher doses of digitoxin and digoxin, prednisolone,
What are the alarm bells with carbimazole use?
Patients should be asked to report symptoms and signs suggestive of infection.
- especially sore throat
- if any sign of infection, a white blood cell count can be performed.
If any neutropenia, stop carbimazole promptly
contact if sore throat, mouth ulcer, bruising, fever, non specific illness, abdominal pain, lack of appetite, jaudince
