Liothyronine Sodium

Thyroid preparations may potentiate toxic effects of digitalis. Increased metabolic rate from thyroid hormone replacement increases digitalis dosage requirements.

Thyroid hormones increase adrenergic effect of catecholamines. May increase risk of precipitating coronary insufficiency, especially in patients with coronary artery disease.

May increase receptor sensitivity and enhance antidepressant activity; transient cardiac arrhythmias have been observed. Thyroid hormone activity may also be enhanced.

Thyroid hormones increase adrenergic effect of catecholamines. May increase risk of precipitating coronary insufficiency, especially in patients with coronary artery disease.

Thyroid hormones increase catabolism of vitamin K-dependent clotting factors, impairing compensatory increases in clotting factor synthesis. Patients stabilized on oral anticoagulants starting thyroid replacement may require reduction in anticoagulant dosage.

Stimulates hepatic microsomal drug-metabolizing enzyme activity, causing increased hepatic degradation of thyroid hormones and increased liothyronine sodium requirements.

Stimulates hepatic microsomal drug-metabolizing enzyme activity, causing increased hepatic degradation of thyroid hormones and increased liothyronine sodium requirements.

May decrease serum thyroxine-binding globulin concentration, altering T3 serum transport. Closely monitor thyroid hormone parameters.

May decrease serum thyroxine-binding globulin concentration, altering T3 serum transport. Closely monitor thyroid hormone parameters.

May cause protein binding site displacement of thyroid hormones, reducing serum protein binding. Total and free T4 may be reduced 20-40%, but most patients remain clinically euthyroid. Closely monitor thyroid hormone parameters.

Bile acid sequestrant that may decrease T3 absorption by binding and delaying or preventing absorption, potentially resulting in hypothyroidism. Administer liothyronine sodium at least 4 hours prior.

May increase serum thyroxine-binding globulin concentration, altering T3 serum transport without affecting free thyroxine concentration. Closely monitor thyroid hormone parameters.

Bile acid sequestrant that may decrease T3 absorption by binding and delaying or preventing absorption, potentially resulting in hypothyroidism. Administer liothyronine sodium at least 4 hours prior.

Bile acid sequestrant that may decrease T3 absorption by binding and delaying or preventing absorption, potentially resulting in hypothyroidism. Administer liothyronine sodium at least 4 hours prior.

May increase serum thyroxine-binding globulin concentration, altering T3 serum transport. Closely monitor thyroid hormone parameters.

Oral estrogens may increase serum thyroxine-binding globulin concentration, altering T3 serum transport. Closely monitor thyroid hormone parameters.

May increase serum thyroxine-binding globulin concentration, altering T3 serum transport. Closely monitor thyroid hormone parameters.

At doses >80 mg IV, furosemide may cause protein binding site displacement. High doses can acutely lower total T4 levels and increase free-T4 fraction by competing for T4-binding sites on TBG, prealbumin, and albumin.

May cause protein binding site displacement of thyroid hormones. Closely monitor thyroid hormone parameters.

May increase serum thyroxine-binding globulin concentration, altering T3 serum transport. Closely monitor thyroid hormone parameters.

May cause protein binding site displacement. Phenytoin reduces serum protein binding of thyroid hormones, with total and FT4 reduced 20-40%, but most patients remain clinically euthyroid. Closely monitor thyroid parameters.

Initiating thyroid replacement therapy may cause increases in insulin requirements. Patients should be closely monitored during initiation of thyroid replacement therapy.

When administered to patients on thyroid preparation, this parenteral anesthetic may cause hypertension and tachycardia. Use with caution and be prepared to treat hypertension.

May increase serum thyroxine-binding globulin concentration, altering T3 serum transport. Closely monitor thyroid hormone parameters.

May increase serum thyroxine-binding globulin concentration, altering T3 serum transport. Closely monitor thyroid hormone parameters.

Fenamates may cause protein binding site displacement of thyroid hormones. Closely monitor thyroid hormone parameters.

Fenamates may cause protein binding site displacement of thyroid hormones. Monitor thyroid hormone parameters.

Estrogen-containing oral contraceptives increase thyroxine-binding globulin, potentially decreasing free levothyroxine. Patients without functioning thyroid gland may need increased thyroid dose.

Reduces serum protein binding of thyroid hormones, with total and FT4 potentially reduced by 20-40%, requiring thyroid hormone monitoring.

At doses >2 g/day, salicylates inhibit binding of T4 and T3 to TBG and transthyretin, with initial increase in serum FT4 followed by normalization. Total T4 levels may decrease by up to 30%. Closely monitor thyroid parameters.

Ion exchange resin known to decrease thyroid hormone absorption, potentially resulting in hypothyroidism. Administer liothyronine sodium at least 4 hours prior or monitor TSH levels.

May decrease serum thyroxine-binding globulin concentration, altering T3 serum transport. Closely monitor thyroid hormone parameters.

May increase serum thyroxine-binding globulin concentration, altering T3 serum transport. Closely monitor thyroid hormone parameters.

May decrease serum thyroxine-binding globulin concentration, altering T3 serum transport. Closely monitor thyroid hormone parameters.

7.8 Tyrosine-Kinase Inhibitors Concurrent use of tyrosine-kinase inhibitors such as imatinib may cause hypothyroidism.

Drug or Drug Class Effect Beta-adrenergic antagonists (e.g., Propranolol >160 mg/day) In patients treated with large doses of propranolol (>160 mg/day), T3 and T4 levels change, TSH levels remain normal, and patients are clinically euthyroid.