Thyroid Flashcards
Propylthiouracil- what is it? What does it treat (3)? Mechanism? Co-administered with?Effects (3)? Side effects (2)? Administered?
Thionamide. Treats 1) daily for hyperthryoid conditions like Graves or functioning tumours 2) to prep for surgery or 3) whilst waiting for radioactive iodine to take effect. It inhibits thyroid peroxidase. Co-administered with propanolol. Reduces thyroid hormone formation, decreases antibody production in Graves and reduces conversion of T4 to T3. Side effects are agranulocytosis and rashes. Orally administered.
Carbimazole- what is it? What does it treat (3)? Mechanism? Co-administered with? Effects (2)? Side effects (2)? Administered? Contra-indications?
Thionamide. Treats 1) daily for hyperthryoid conditions like Graves or functioning tumours 2) to prep for surgery or 3) whilst waiting for radioactive iodine to take effect. It inhibits thyroid peroxidase. Co-administered with propanolol. Reduces thyroid hormone formation and decreases antibody production in Graves. Side effects are agranulocytosis and rashes. Orally administered. Can cross the placenta and pass into breastmilk (cretinism).
Potassium iodide- what does it treat (2)? Mechanism? Effect (2)? Side effects? Pharmacokinetics?
Used to prep patients for surgery and for severe thyrotoxic crisis. Wolff-chaikoff effect- inhibits iodination of thyroglobulin and production of H202. Reduces symptoms within 1-2 days and vascularity and size of glald within 10-14 days. Causes allergic reactions e.g. rashes. Oral administration, 10 days continuous dosing.
Radioiodine- what does it treat (2)? Mechanism? Administration instructions? Half life? Concerns? Contra-indications? What are low, tracer doses used for? What could be used as an alternative?
Treats hyperthyroid conditions and thyroid cancers (500 vs 3000 MBq). Accumulates in the colloid, emits B particles and hence destroys follicular cells. Stop any other anti-thyroid drugs 7-10 days before to allow maximum uptake and administer as a single oral dose. Half-life of 8 days, no longer radioactive after 2 months. Can’t be around children for 2 weeks, can’t give to pregnant or breastfeeding. Tests thyroid gland pathology e.g. whether a toxic nodule or graves. An alternatve is technetium 99 pertechnetate.
Levothyroxine sodium- what is it? What can it be used to treat (4)? Side effects of over-replacement? Half life? Administration? Clearance? What could affect clearance (3)?
Tetraiodothyronine. Can be used to treat 1) iatrogenic primary hypothyroidism, 2) autoimmune primary hypothyroidism, 3) secondary hypothyroidism or 4) myxoedema coma (IV). Side effects: increased bone turnover–> osteoporosis, tachycardia, weigh loss and terror (from increased b-adrenergic sensitivity). Half life of 6 days and taken orally. Clearance takes 6 days. Pregnancy, malnutrition and other drugs like phenytoin, all can change the concentration of TBG in the blood and hence affect clearance.
Liothyronine sodium- what is it? What can it be used to treat (4)? Side effects of over-replacement? Why is it specifically not commonly used? Half life? Administration? Clearance? What could affect clearance (3)?
Triiodothyronine. Can be used to treat 1) iatrogenic primary hypothyroidism, 2) autoimmune primary hypothyroidism, 3) secondary hypothyroidism or 4) myxoedema coma (IV). Side effects: increased bone turnover–> osteoporosis, tachycardia, weigh loss and terror (from increased b-adrenergic sensitivity). T3 specifically has been associated with symptoms of palpitations and anxiety. Half life of 2.5 days and taken orally. Clearance takes hours. Pregnancy, malnutrition and other drugs like phenytoin, all can change the concentration of TBG in the blood and hence affect cl
