Anti-thyroid drugs Flashcards
1
Q
What are examples of anti-thyroid drugs?
A
- Carbimazole
* Propylthiouracil
2
Q
What is the method of action of anti-thyroid drugs?
A
- Metabolised to methimazole
- Inhibits the thyroid peroxidase enzyme from coupling and iodinating the tyrosine residues on thyroglobulin
- ↓ uptake and concentration of inorganic iodine by the thyroid
- ↓ formation of thyroxine
3
Q
What are the indications for anti-thyroid drugs?
A
- Hyperthyroidism
- Preparation for thyroidectomy in hyperthyroidism
- Therapy prior to and post radio-iodine treatment
4
Q
What are the contraindications for anti-thyroid drugs?
A
- Breast feeding
- Severe liver disorder
- Serious blood disorder
- Intrathoracic goitre – caution
- Pregnancy – lowest dose only and stop ¾ weeks before giving birth
- Bone marrow depression – caution
- Mild/moderate liver disease – caution
5
Q
What are the side effects of anti-thyroid drugs?
A
- Nausea
- Headache
- Dizziness
- Skin rashes/itching
- GI upset
- Hair thinning
- Change in taste
- Bone marrow depression symptoms: fever, infections, mouth ulcers, unusually tired – stop taking medication
- Jaundice
- Muscle pain/weakness
- Nerve pain
- Swelling of lymph nodes
- Swelling of glands in your mouth
- Low blood sugar
6
Q
What are the drug interactions with anti-thyroid drugs?
A
- Radioactive iodine
- Anticoagulants – effects ↑ as carbimazole is a Vit K antagonist
- Antiplatelets
- Theophylline – levels ↑ so theophylline dose needs to be reduced
- Prednisolone - ↑ clearance
- Erythromycin – inhibit metabolism → ↓ clearance
- Digoxin - ↑ levels so dose needs to be reduced
- Beta blockers - ↑ clearance
7
Q
What organ eliminates anti-thyroid drugs?
A
Kidney
8
Q
What information should be given to a patient taking anti-thyroid drugs?
A
• Symptoms should improve within 1-3 weeks, however the full benefit takes 4-8 weeks
