| classification of drug | name | mechanism | use | side effects | comments | disadv | ||||||||
| Anti-thyroid drugs | ||||||||||||||
| 1-thioamides | 1-inhibit thyroperoxidase catalyse oxidation reaction so inhibit iodide organification & inhibit coupling | hyper throdism | A-common :pruritic rashes & drug fever B-rare :1-reversible agranulocytosis 2-headache 3-nausia | 3 drugs are taken orally ,and are plasma protein binding | slow onset (3 or 4 weeks ) | |||||||||
| carbimazole | pro-drug ,inactive invitro converted invivo to active methimazole | |||||||||||||
| methimazole | 10 times more active than propyl thiouracil ,+half life so it is taken once daily | |||||||||||||
| propylthiouracil | the last mech + inhibit monodeiodination of T4 to T3 so it is used in severe hyper function | thyroid storm | (-)H.life >4 times daily , has highest PBB so it is used during pregnancy (less harmful to foetus) | |||||||||||
| 2-iodides | KI soln | iodide act through block H2O2 generation | taken 2 weeks before surgical removal of the gland to reduce muscularity and (-) size of gland | iodism : 1-inf and pain in salivary glands 2-achnei-form rashes 3-drug fever 4-tacrimation & conjunctivities | action from 2 to 8 weeks then no effect | |||||||||
| 3-radioactive iodine (I131) | *Xray>pass within tissues >non effective *B -radn =therapeutic effect | action is delayed after 1 or 2 months *taken as sodium salt soln | 1-contraindicated in childeren and during pregnancy 2-delayed action | |||||||||||
| 4-Ipodate | 1-inhibit monodeiodination of T4>T3 2-due to its I content it block H2o2 generation (-) t3&t4 | thyrotoxicosis esp. in thy. Storm | iodism | |||||||||||
| Anion inhibitors | prerchlorate or thiocyanate | (-) I trapping | due to high toxicity ,it is not used now | |||||||||||
| propranolol | B -adrenaceptor blocker | to inhibit tremors & abolish +H.R but it is not affect BMR | in initial treat. Of thioamides or (I131) w has delayed onset | |||||||||||
| hypothyrodism | replacement therapy | the 3 are syn and in tablet and best one is T4 | ||||||||||||
| T4 | adv : 1-low cost 2-+expiry date 3-+half life 4-part change to T3 | |||||||||||||
| T3 | 1-(-) shelf life 2-high cost 3-+ risk of cardiac toxicity | |||||||||||||
| desicated thyroid gland | 1-full of protein (-antigenic reactions) 2-level of hormones can not be determined exactly 3-expiry date can not well determined | |||||||||||||