Antithyroid drugs

Question 1

Example of an Antithyroid drug (used drugbank.com)

Answer 1

Carbimazole

Question 2

How do Antithyroid drugs work?

Answer 2

Decreases the uptake and concentration of inorganic iodine by thyroid, it also reduces the formation of di-iodotyrosine and thyroxine. Once converted to its active form of methimazole, it prevents the thyroid peroxidase enzyme from coupling and iodinating the tyrosine residues on thyroglobulin, hence reducing the production of the thyroid hormones T3 and T4.

Question 3

Indications for Antithyroid drugs (patient.co.uk)

Answer 3

For the treatment of hyperthyroidism and thyrotoxicosis.

It is also used to prepare patients for thyroidectomy.

Question 4

Contraindications for Antithyroid drugs (WebMD, boots)

Answer 4

Carbimazole should be used with caution in: the elderly, people with mild to moderate liver disease, pregnant women, people with swelling of the thyroid gland (goitre).

It should not be used in:
Patients with an allergy to carbimazole or to any other ingredients in the medicine or to other anti-thyroid drugs including propylthiouracil, people with severe liver disease, people with serious blood disorders, women who are breastfeeding, patients who are unable to tolerate galactose, people who have too little of the lactase enzyme or are unable to absorb glucose or galactose.

Question 5

Side effects of Antithyroid drugs (patient.co.uk)

Answer 5

Feeling sick (nausea), stomach upset

Stick to simple foods - avoid rich or spicy meals

Headache, muscle and joint pain Ask your pharmacist to recommend a suitable painkiller

Skin rash, itching Let your doctor know about this, as treatment with an antihistamine medicine may help

Changes to the way things taste, hair loss These should pass after the first few weeks

Carbimazole can cause a rare but serious side-effect which reduces the numbers of blood cells which fight infection and help to stop bleeding. If you develop any of the following, let your doctor know straightaway:
A sore throat.
Mouth ulcers.
A high temperature (fever).
Any unusual bruising or bleeding.
If you feel unusually tired, or if you feel you are getting an infection.

Question 6

Interactions of Antithyroid drug (used drugbank.com)

Answer 6

Increases serum concentration of Acetyldigitoxin, Ambroxol acefyllinate, Experimental Aminophylline, Deslanoside, Digitoxin, Digoxin, Dyphyllin, Investigational Oleandrin, Ouabain, Tizanidine and Theophylline

Decreases decrease the anticoagulant activities of Acenocoumarol, Dicoumarol, Ethyl biscoumacetate, Fluindione, Phenindione, Phenprocoumon, Warfarin

Decreases serum concentration of Prednisolone

Decreases therapeutic efficacy of Sodium Iodide I-131

Question 7

Elimination of Antithyroid drugs (medicines.org)

Answer 7

Renal

Question 8

Patient information on Antithyroid drugs (patient.co.uk)

Answer 8

Antithyroid medicines like carbimazole are used to treat an overactive thyroid gland (hyperthyroidism), which is also known as thyrotoxicosis. When your thyroid gland produces too much thyroid hormone, it can cause many of your body’s functions to speed up, and this leads to symptoms such as losing weight, sweating, feeling irritable or shaky, and diarrhoea. You also may feel tired or worried, and develop menstrual problems. Carbimazole is the most commonly used medicine for hyperthyroidism. It works by reducing the amount of thyroid hormones which your thyroid gland makes.