Thyroid and anti-thyroid Flashcards
Which drugs inhibit the conversion of T4 to T3
- Propylthiouracil
- propranolol
- glucocorticoids
- iopanoic acid
What are the effects of hyperthyroidism (thyrotoxicosis)
- Increased basil metabolic rate, gluconeogenesis, gluconeogenesis
- Increased heart rate, cardiac output, arrhythmias, angina
- Decreased cholesterol, Triglycerides
- Nervousness and anxiety
- Muscle weakness, fatigue, increased tendon reflexes, hypercalcemia, osteoporosis
- Increased appetite, diarrhoea
- anaemia
- menstrual irregularities, increased fertility
- Periorbital Edema exopathalmos
- Warm moist skin, heat intolerance, thin hair
What effects of hypothyroidism myxoedema
- Decreased basal metabolic rate, hypoglycemia, hypercholesteremia, hypertriglyceridaemia
- decreased heart rate, low output cardiac failure, pericardial effusion
- Lethargic in mental retardation
- stiffness and muscle fatigue
- decreased appetite, constipation
- anaemia
- Menorrhagia, infertility, decreased libido, impotence
- puffy face, large tongue
- Pale, dry skin, intolerance to cold, brittle hair and nails.
Name the drugs used as replacement therapy in a hypothyroid states
- Levothyroxin sodium (T4)
- Liothyronine (T3)
- Combination of T4 and T3 (4:1)
What are the therapeutic uses of drugs used in hypothyroid states
- Cretinism and myxoedema- levothyroxine. 12.5 to 25 mcg per day for elderly impatient with coronary artery disease. 50 to 100 mcg for young adults
- Myxoedema Coma
- Benign thyroid nodule
- thyroid carcinoma
What is the treatment of myxoedema coma
- levothyroxine
- IV hydrocortisone
- rewarming with blankets
- correction of electrolyte imbalance
- ventilatory support may be required
- antibiotics if infection is the cause
Classify anti-thyroid drugs
- Thyroid hormone synthesis inhibitors
- Inhibitors Of iodide trapping
- hormone release inhibitors
- thyroid tissue destroying agents
- others
Name thyroid hormone synthesis inhibitors (thioamides or thiourea derivatives)
1. Propylthiouracil
2. Methimazole
3. Carbimazole
Name inhibitors of iodide trapping
- Thiocyanate
- Pirchlorates
Name hormone release inhibitors used in hyperthyroidism states
- Iodine
- iodides of sodium and potassium
- organic iodide
Name thyroid tissue destroying agent
- Radioactive iodine (131 I)
Name other drugs used in hyperthyroidism
- Propranolol
- atenolol
- diltiazem
- dexamethasone
- Metaprolol
What are the mechanisms of action of thioamides
- Inhibit thyroid peroxidase enzyme
- Inhibit iodination of tyrosine residues
- Inhibit coupling of iodotyrosine

Which thioamide Is most rapidly absorbed
Propylthiouracil
What metabolite is created from carbimazole
Methimazole
What are the adverse effects of anti-thyroids
- Skin rashes
- joint pain
- fever
- hepatitis
- nephritis
- agranulocytosis (rare)
- hypothyroidism
What are the adverse effects of anti-thyroid drugs
thyrotoxicosis 
Which type of anti-thyroids cannot be used clinically
Thiocynates and perchlorates which are inhibitors of iodide trapping
Which two drugs can be used pre-operatively before thyroectomy and in thyroid storm
1. Lugols iodine
2. Ipodate sodium and iopanoic acid
 What drug can be used for prophylaxis of endemic goitre
Iodized salt
What are the side effects of using iodine 
- Type III Hypersensitivity reaction
-  headache, sneezing, irritation of eyes with swelling of eyelids
- Pulmonary oedema
- foetal goitre
Which drug emmits beta particles and what is its function
Radioactive iodine. Beta particles cost destruction of follicular cells leading to fibrosis and correction of hyperthyroid state
What are the contraindications of radioactive iodine
Pregnancy, children and nursing mothers
What are the advantages of radioactive iodine
Permanently cures hyperthyroidism
What is propranolol and other beta blockers used to treat hyperthyroidism
Prevents the conversion of T4 to T3
What is thyrotoxic crisis/thyroid storm
Severe hypermetabolic state do the very high levels of circulating thyroid hormone. Symptoms are nausea, vomiting, diarrhoea, mental confusion, cardiac arrhythmias and hyperprexia
Treatment of thyrotoxic crisis/thyroid storm
- Hospitalization
- supportive care
- Propylthiouracil administration via nasogastric tube
- Oral iodide to inhibit thyroid hormones
- propranolol IV or diltiazem
- Ivy Hydrocortisone- Inhibit conversion of T4 to T3 and corrects adrenal insufficiency