Agent | Indications | Dosage | Comments |
Thyroid |
Levothyroxine (T4, L-thyroxine) | Hypothyroidism, myxedema coma | Initial replacement: 25 50 g PO qd | Converted to T3 in periphery |
Maximum replacement: 200 g PO qd | Follow TSH for normalization and patient's clinical status |
In critically ill with myxedema coma: 200 500 g IV/day slowly | For stupor or coma, treat with 200 500 g IV bolus followed by 75 g/day; consider hydrocortisone 50 100 mg IV q8h 5 d as adjunctive therapy for hypocortisolism |
Half-life: euthyroid, 6 d; hypothyroid, 8 d; hyperthyroid, 3 d |
IV dose = 75% of PO dose (for replacement therapy) |
Preferred over T3 for critically ill patients |
Many experts prefer the lower doses initially for safety, especially in the elderly, comatose, and those with heart disease |
May precipitate angina or arrhythmias |
Liothyronine (T3, triiodothyronine) | Hypothyroidism, myxedema coma | Replacement: 25 75 g PO qd | Assessment of therapy is more difficult; wait at least four hours after IV dose |
Myxedema coma: 12.5 25 g IV q6h | Half-life: euthyroid, 24 h; hypothyroid, 38 h; hyperthyroid, 17 h |
Pituitary/Adrenal |
Synthetic ACTH (cosyntropin) | Screening test for adrenal insufficiency | 250 g (25 units) IV/IM | Some authors recommend using smaller doses such as 1 g for assessment of HPA axis |
Normal function is indicated by control cortisol level >5 g/dl and 30 min post level >18 g/dl with an increase of 7 g/dl above control |
Small doses of prednisone will not affect cortisol response |
Dexamethasone does not affect cortisol response |
Fludrocortisone | Mineralo-corticoid replacement in primary adrenal insufficiency | 50 200 g PO qd | Titrated to achieve normal serum potassium and blood pressure |
Not required in secondary adrenal insufficiency |
Hydrocortisone | Replacement | 25 mg IV/PO q AM and 12.5 mg IV/PO q PM | For equivalent corticosteroid dosages, see Table 6.1 |
Stress | 50 100 mg IV/PO q8h | For treatment of adrenal insufficiency complicating critical illness, maximum dose of glucocorticoid should be equivalent to hydrocortisone 300 mg/d |
Preoperative | 1 d preoperatively: 25 mg IV/PO at 6 PM and midnight | For patients who may have adrenal insufficiency |
Day of operation: 50 mg IV during surgery |
Postoperative: 50 mg IV q8h 24 h, then 25 mg IV/PO q8h 24 48 h |
Desmopressin | Diabetes insipidus | Intranasal: 10 40 g in 1 3 divided doses daily | May cause hypertension, water retention, headache, abdominal cramps; swelling and burning may occur at the injection site after SC administration |
SC/IV: 2 4 g in 2 divided doses daily |
HPA, hypothalamic-pituitary-adrenal; IM, intramuscular; IV, intravenous; PO, by mouth; SC, subcutaneous; TSH, thyroid stimulating hormone |