Medication Summary
With the exception of antithyroid drugs for Graves disease, most medications listed here are essentially for replacement therapy.
Glucocorticoids
Class Summary
Glucocorticoids are used in the replacement therapy associated with adrenal failure. Significant trauma can acutely increase the need for such treatment.
Hydrocortisone (Hydrocortone, Hydrocort, Cortef, Hydro-Tex)
Useful in treatment of diverse group of diseases, especially autoimmune and inflammatory diseases. Used for primary adrenal failure. Has weak mineralocorticoid activity. Individualize dosing.
Thyroid hormones
Class Summary
These agents are used for thyroid replacement in hypothyroidism.
Levothyroxine (Synthroid, Levoxyl, Levothroid, Unithroid, Tirosint)
DOC due to stability, cost, lack of foreign-protein allergens, and long half-life (qd dosing). T4 converted to T3 intracellularly, and T4 administration produces both hormones. In active form, influences growth and maturation of tissues. Involved in normal growth, metabolism, and development.
Infants and children require more T4/kg than do adults.
Dosing depends on age and comorbidity.
Antithyroid agents
Class Summary
These drugs act by inhibiting TPO-catalyzed reactions to block iodine organification and by inhibiting peripheral deiodination of T4/T3. (The last effect is seen only by propylthiouracil [PTU].)
Propylthiouracil (PTU)
Derivative of thiourea that inhibits organification of iodine by thyroid gland. Blocks oxidation of iodine in thyroid gland, thereby inhibiting thyroid hormone synthesis; inhibits T4 to T3 conversion (advantage over other agents). Ten times less active than methimazole.
Relatively safe in pregnancy and breastfeeding due to tight bond to plasma proteins.
Methimazole (Tapazole)
Inhibits thyroid hormone by blocking oxidation of iodine in thyroid gland. However, not known to inhibit peripheral conversion of thyroid hormone. Taper gradually to the minimum dose required to keep the patient clinically euthyroid and to avoid fetal hypothyroidism. Cases of fetal aplasia cutis are reported.
Antidiabetic agents
Class Summary
These agents are used for type 1 diabetes mellitus replacement.
Insulin regular human (Humulin, Novolin), NPH Insulin (Humulin, Novolin), Long-acting basal insulin analogs (detemir, glargine), Fast-acting prandial insulin analogs (lispro, aspart, glulisine).
Stimulates proper utilization of glucose by the cells and reduces blood sugar levels. Wide variety derived from pork, beef, and synthetic human derivatives. Various preparations with variable onsets of actions; shortest and quickest is lispro insulin, and longest acting is ultralente insulin. Not administered PO because becomes denatured by acid and intestinal peptidases. Can be administered IV/IM/SC. Nasal administration may be available soon, depending on required preparation.
Dosing individualized based on lifestyle, dietary compliance, infections, and surgeries.
Mineralocorticoids
Class Summary
These are employed in partial replacement therapy for primary and secondary adrenocortical insufficiency.
Fludrocortisone (Florinef)
Mineralocorticoid required for conservation of Na and renal loss of K. Maintains blood pressure and intravascular/extracellular volume.
Vitamins
Class Summary
Vitamin B-12 replacement in pernicious anemia. Megaloblastic anemia must be further evaluated to differentiate folate deficiency from vitamin B-12 deficiency, because the latter requires life-long treatment. When cyanocobalamin is deficient mainly due to malabsorption, it must be replaced via the NG route. Hydroxocobalamin is the more potent vitamin B-12 variant, because it forms a tight bond with plasma proteins and stays in circulation longer. Hydroxocobalamin may be a good complexing agent for cyanide poisoning. Possible effective antidote.
Cyanocobalamin (Crystamine, Cyomin, Crysti 1000, Nascobal)
Deoxyadenosylcobalamin and hydroxocobalamin are active forms of vitamin B-12 in humans. Vitamin B-12 is synthesized by microbes but not by humans or plants. Vitamin B-12 deficiency may result from intrinsic factor deficiency (pernicious anemia), partial or total gastrectomy, or diseases of the distal ileum.
