Thyroid & Anti-Thyroid Drugs Flashcards
Levothyroxine- Na (L-T4) (Synthroid, Levoxyl, Levothyroid, Unithyroid)- Mech of Action
T4 Supplement
Levothyroxine- Na (L-T4) (Synthroid, Levoxyl, Levothyroid, Unithyroid)- Clinical Use
hypothyroidism
cretenism
TSH suppression therapy for thyroid cancer
occasionally TSH suppression in nontoxic goiter
Levothyroxine- Na (L-T4) (Synthroid, Levoxyl, Levothyroid, Unithyroid)- Adverse Effects/Contraindications
narrow therapeutic window
hyperthyroidism (heat intolerance, agitation, etc.)
Levothyroxine- Na (L-T4) (Synthroid, Levoxyl, Levothyroid, Unithyroid)- Drug Rxns
levels are decreased by cyp inducers (phenytoin, rifampin, carbemazepine)
absorption decreased by cholestyramine, iron, Ca supplements, A1OH, and soy products
can increase the action of Warfarin, TCAs, and amiodarone
Liothyronine-Na (L-T3) (Cytomel, Triostat)- Mech of Action
T3 supplement
Liothyronine-Na (L-T3) (Cytomel, Triostat)- Clinical Use
occasionally used for rapid onset or shorter lasting action: myxedemic coma
Prep for (131)I therapy for thyroid cancer
Liothyronine-Na (L-T3) (Cytomel, Triostat)- Adverse Effects/Contraindications
hyperthyroidism
more potent than T4- may have more serious side effects such as cardiac arrhythmias
Liotrix (Thyrolar)- Mech of Action
T3 and T4 supplement
Liotrix (Thyrolar)- Clinical Use
same as T4
Liotrix (Thyrolar)- Adverse Effects/Contraindications
Same as T4
Liotrix (Thyrolar)- Drug Rxns
Same as T4
Propylthiouracil (PTU), Methimazole (Tapazole)- Mech of Action
INHIBIT IODINE ORGANIFICATION (THE PEROXIDASE CATALYZED IODINATION AND COUPLING RXNS)
PROPYLTHIOURACIL ALSO INHIBITS PERIPHERAL DEIODINATION OF T4 TO T3
Propylthiouracil (PTU), Methimazole (Tapazole)- Clinical Use
Hyperthyroidism
Control of elevated T4 in Graves’ disease while awaiting effet of irradiation
Preparation for thyroid surgery
Propylthiouracil (PTU)- Adverse Effects/Contraindications
AGRANULOCYTOSIS (NOT DOSE DEPENDENT)
MILD GRANULOCYTOPENIA
MOST COMMON- URTICARIA/RASH
if urticaria/rash occurs, change to methimazole
PREFERRED IN NURSING MOTHERS- VERY LITTLE IN MILK
Methimazole (Tapazole)- Adverse Effects/Contraindications
DOSE DEPENDENT AGRANULOCYTOSIS
MILD GRANULOCYTOPENIA
MOST COMMON- URTICARIA/RASH
NOT RECOMMENDED IN NURSING MOTHERS
Iodide (Iodopen)- Mech of Action
AT HIGH DOSES INHIBITS IODIDE UPTAKE, AND SYTHESIS OF IODOTYROSINE & IODOTHYRONINE
ALSO INHIBIT HORMONE RELEASE
Iodide (Iodopen)- Clinical Use
PEOP. FOR HYPERTHYROID STATE
THYROID STORM
PROPHYLACTIC FOR PROTECTION IN RADIATION EXPOSURE
EFFECTS WANE OVER TIME, SO MUST BE USED IN CONJUNCTION WITH OTHER DRUGS.
Iodide (Iodopen)- Adverse Effects/Contraindications
Hypersensitivity when administered IV- angioedema
Radioactive iodide I(131)- Mech of Action
NA(131)I IS CONCENTRATED IN THE THYROID WHERE THE BETA AND GAMMA RADIATION WILL DESTROY ALL OR PART OF THE TISSUE
Radioactive iodide I(131)- Absorption, Distribution
PO
Radioactive iodide I(131)- Clinical Use
ABLATION THERAPY FOR HYPERTHYROIDISM
Adjuvant therapy with B-blockers or other drugs while awaiting full effectiveness is OK
Radioactive iodide I(131)- Adverse Effects/Contraindications
OVERTREATMENT RESULTS IN HYPOTHYROIDISM
CONTRAINDICATED IN PREGNANCY, PATIENTS UNDER THE AGE OF 35.
Radioactive iodide I(131)- Drug Rxns
High dose iodide
B-blockers- Mech of Action
INHIBIT DEIODINATION (CONVERSION OF T4 TO T3) DECREASE HR, CONTRACTILITY, ARRHYTHMIAS
