levothyroxine

Adult Dosing .

Dosage forms:  CAP: 13 mcg, 25 mcg, 50 mcg, 75 mcg, 88 mcg, 100 mcg, 112 mcg, 125 mcg, 137 mcg, 150 mcg, 175 mcg, 200 mcg; TAB: 25 mcg, 50 mcg, 75 mcg, 88 mcg, 100 mcg, 112 mcg, 125 mcg, 137 mcg, 150 mcg, 175 mcg, 200 mcg, 300 mcg; INJ: various

Special Note

[thyroid product equivalencies]

Info: for product conversion purposes, 100 mcg levothyroxine = 25 mcg liothyronine = 60-65 mg thyroid (porcine) = 1 grain liotrix

hypothyroidism

[50-200 mcg PO qd]

Start: 1.6 mcg/kg/dose PO qd, then adjust dose by 12.5-25 mcg/day q4-6wk; Info: adjust dose based on TFTs; doses >300 mcg/day rarely needed; use lower start dose, then adjust dose q6-8wk in elderly pts and pts w/ cardiac dz; dose adjustments may be needed during pregnancy and/or immed. postpartum; give PO form on empty stomach, 30-60min before breakfast; IM/IV dose is 50-75% of PO dose

TSH suppression

[individualize dose PO qd]

Info: for pts w/ thyrotropin-dependent well-differentiated thyroid CA; adjust dose to suppress TSH to levels based on clinical status; dose adjustments may be needed during pregnancy and/or immed. postpartum; give on empty stomach, 30-60min before breakfast

myxedema coma

[300-500 mcg IV x1, then 50-100 mcg IV qd]

Info: switch to PO regimen when pt clinically stable; use lower start dose in elderly pts and pts w/ cardiac dz

renal dosing

[not defined]

renal impairment: not defined

HD/PD: not defined

hepatic dosing

[not defined]

Peds Dosing .

Dosage forms:  CAP: 13 mcg, 25 mcg, 50 mcg, 75 mcg, 88 mcg, 100 mcg, 112 mcg, 125 mcg, 137 mcg, 150 mcg, 175 mcg, 200 mcg; TAB: 25 mcg, 50 mcg, 75 mcg, 88 mcg, 100 mcg, 112 mcg, 125 mcg, 137 mcg, 150 mcg, 175 mcg, 200 mcg, 300 mcg; INJ: various

Special Note

[thyroid product equivalencies]

Info: for product conversion purposes, 100 mcg levothyroxine = 25 mcg liothyronine = 60-65 mg thyroid (porcine) = 1 grain liotrix

hypothyroidism

[<3 mo]

Dose: individualize dose PO qd; Start: 10-15 mcg/kg/dose PO qd, then adjust dose q2wk; Info: adjust dose based on TFTs; use lower start dose and incr. dose q4-6wk if risk for cardiac failure; give PO form on empty stomach, 30-60min before morning meal; IM/IV dose is 50-75% of PO dose

[3-5 mo]

Dose: individualize dose PO qd; Start: 8-10 mcg/kg/dose PO qd, then adjust dose q2wk; Info: adjust dose based on TFTs; give PO form on empty stomach, 30-60min before morning meal; IM/IV dose is 50-75% of PO dose

[6-11 mo]

Dose: individualize dose PO qd; Start: 6-8 mcg/kg/dose PO qd, then adjust dose q2wk; Info: adjust dose based on TFTs; give PO form on empty stomach, 30-60min before morning meal; IM/IV dose is 50-75% of PO dose

[1-5 yo]

Dose: individualize dose PO qd; Start: 5-6 mcg/kg/dose PO qd, then adjust dose q2wk; Info: adjust dose based on TFTs; start 25% usual start dose, then incr. by 25% usual start dose qwk if hyperactivity risk; give PO form on empty stomach, 30-60min before breakfast; IM/IV dose is 50-75% of PO dose

[6-12 yo]

Dose: individualize dose PO qd; Start: 4-5 mcg/kg/dose PO qd, then adjust dose q2wk; Info: adjust dose based on TFTs; start 25% usual start dose, then incr. by 25% usual start dose qwk if hyperactivity risk; give PO form on empty stomach, 30-60min before breakfast; IM/IV dose is 50-75% of PO dose

[>12 yo, growth/puberty incomplete]

Dose: individualize dose PO qd; Start: 2-3 mcg/kg/dose PO qd, then adjust dose q2wk; Info: adjust dose based on TFTs; start 25% usual start dose, then incr. by 25% usual start dose qwk if hyperactivity risk; give PO form on empty stomach, 30-60min before breakfast; IM/IV dose is 50-75% of PO dose

[>12 yo, growth/puberty complete]

Dose: 50-200 mcg PO qd; Start: 1.6 mcg/kg/dose PO qd, then adjust dose by 12.5-25 mcg/day q4-6wk; Info: adjust dose based on TFTs; doses >300 mcg/day rarely needed; use lower start dose, then adjust dose q6-8wk in pts w/ cardiac dz; start 25% usual start dose, then incr. by 25% usual start dose qwk if hyperactivity risk; dose adjustments may be needed during pregnancy and/or immed. postpartum; give PO form on empty stomach, 30-60min before breakfast; IM/IV dose is 50-75% of PO dose

TSH suppression

[individualize dose PO qd]

Info: for pts w/ thyrotropin-dependent well-differentiated thyroid CA; adjust dose to suppress TSH to levels based on clinical status; dose adjustments may be needed during pregnancy and/or immed. postpartum; give on empty stomach, 30-60min before breakfast

renal dosing

[not defined]

renal impairment: not defined

HD/PD: not defined

hepatic dosing

[not defined]