Table 4.

Treatment of thyrotoxic storm

	Doses and formulations	Notes
Lowering of thyroid hormone synthesis and/or secretion
Antithyroid drugs	Propylthiouracil 250 mg every 4 h, after a loading dose of 500–1000 mg, or thiamazole 20 mg every 6 h	Antithyroid drugs in high doses block thyroid hormone synthesis; propylthiouracil is preferred over thiamazole because of the additional effect of blocking T4 to T3 conversion, although there is some disagreement in avoiding thiamazole in this setting122 since no data show the superior efficacy of propylthiouracil in thyroid storm
Inorganic iodine	Saturated solution of potassium iodide, 5 drops (0·25 mL or 250 mg) every 6 h, given orally (or 1 g intravenously over 12 h)	Inorganic iodine decreases release of preformed T4 and T3 and should be given 1 h after antithyroid drugs because iodine can increase hormone production by acting as a substrate for the thyroid synthesis of T4 and T3 if synthesis has not already been blocked with antithyroid drugs
Reduction of circulating thyroid hormones*
Bile acid sequestrants	Doses of colestyramine up to 4 g every 6 h are recommended	After conjugation in the liver, free thyroid hormones are excreted in the intestine and then reabsorbed into the circulation; colestyramine has been shown to decrease serum thyroid hormone concentrations more rapidly and thoroughly than treatment with thionamide alone by enhancing thyroid hormone faecal excretion via sequestration of free hormones in the intestine123
Control of the peripheral effects of thyroid hormone†
β blockers	Propranolol 60–80 mg every 4 h, orally (it can also be given intravenously); other β-blocking drugs are also useful	β blockers can control the peripheral effects of excess thyroid hormones, in addition to slightly decreasing T4 to T3 conversion; in patients with heart failure or contraindication to β blockers, such as asthma or bronchospasm, strict monitoring and extreme caution is recommended
Resolution of systemic manifestations
Glucocorticoids	Hydrocortisone, at a dose of 100 mg every 8 h after an intravenous loading dose of 300 mg, or dexamethasone, at a dose of 2 mg twice a day, intravenously or orally	Glucocorticoids reduce T4 to T3 conversion and treat the potential risk of adrenal insufficiency due to severe thyrotoxicosis124
Paracetamol (acetaminophen), external cooling	650 mg every 6–8 h as needed	Fever should be treated with paracetamol; salicylates should be avoided, because they increase free T3 and free T4 concentrations by inhibiting T3 and T4 binding to serum proteins
Treatment of precipitating illness
Dependent on underlying illness	Not applicable	The underlying illness that triggered the thyroid storm should be diagnosed and treated appropriately

T₄=thyroxine. T₃=tri-iodothyronine.

^*In severe cases or in those refractory to conventional treatments, plasmapheresis has been used to reduce T₃ and T₄ concentrations from plasma in 36 h,¹¹⁸ and also removes pro-inflammatory cytokines and antibodies.

^†In patients for whom β blockers are contraindicated, calcium-channel blockers, such as diltiazem, can be used.¹²⁵