Drilldown: Medicines
Medicines > fda max 
:
3600 mg/day; off-label doses higher are common but bioavailability saturates well below this or
No fixed maximum; titrated to TSH target
& routes:
oral
:
3600 mg/day; off-label doses higher are common but bioavailability saturates well below this or
No fixed maximum; titrated to TSH target
& routes:
oral Use the filters below to narrow your results.
generic:
brand:
classes:
mechanism:
None (1) ·
Synthetic T4 (thyroxine); peripherally deiodinated to T3 (triiodothyronine), the active hormone. '"`UNIQ--vote-00000031-QINU`"' Narrow therapeutic index; brand-to-generic switches can shift TSH and require re-titration'"`UNIQ--ref-00000032-QINU`"'. (1) ·
'"`UNIQ--vote-00000016-QINU`"' Brand-to-brand and lot-to-lot variability in T3:T4 ratio is greater than with synthetic levothyroxine, which is why endocrine guidelines prefer the synthetic'"`UNIQ--ref-00000017-QINU`"'. (1)
uses:
'"`UNIQ--vote-00000018-QINU`"', '"`UNIQ--vote-00000019-QINU`"' (1) ·
'"`UNIQ--vote-00000021-QINU`"', '"`UNIQ--vote-00000022-QINU`"', '"`UNIQ--vote-00000023-QINU`"', '"`UNIQ--vote-00000024-QINU`"', '"`UNIQ--vote-00000025-QINU`"', '"`UNIQ--vote-00000026-QINU`"', '"`UNIQ--vote-00000027-QINU`"', '"`UNIQ--vote-00000028-QINU`"' (1) ·
'"`UNIQ--vote-00000033-QINU`"', '"`UNIQ--vote-00000034-QINU`"', '"`UNIQ--vote-00000035-QINU`"' (1)
starting dose:
1.6 mcg/kg/d in young healthy adults; 25-50 mcg/d in elderly or cardiac disease, titrated by TSH at 6-8 weeks (1) ·
30 mg PO daily (1/2 grain); titrate by TSH at 6-8 weeks; 60 mg desiccated thyroid is approximately equivalent to 88-100 mcg levothyroxine (1) ·
300 mg PO at bedtime night 1, 300 mg BID day 2, 300 mg TID day 3; titrate to clinical effect, commonly 1800-3600 mg/day divided TID (1)
preparations:
15, 30, 60, 90, 120, 180, 240, 300 mg tablets (1/4 to 5 grains; 1 grain = 60 mg) (1) ·
25, 50, 75, 88, 100, 112, 125, 137, 150, 175, 200, 300 mcg tablets; oral capsule and IV/IM also available (1) ·
Capsules 100, 300, 400 mg; tablets 600, 800 mg; oral solution 250 mg/5 mL; Gralise ER tablets 300, 600 mg (once-daily); Horizant ER tablets 300, 600 mg (gabapentin enacarbil, an inactive parent compound metabolized to gabapentin in vivo) (1)
fda max: (Click arrow to add another value)
routes: (Click arrow to add another value)
onset:
halflife:
bioavailability:
'''Saturable''' via the LAT-1 amino-acid transporter, producing nonlinear pharmacokinetics: ~60% at 300 mg single dose, falling to ~35% at 1200 mg single dose'"`UNIQ--ref-0000002A-QINU`"' (1) ·
40-80% (oral); reduced by food, calcium, iron, PPIs, fiber; take fasting with water'"`UNIQ--ref-00000037-QINU`"' (1) ·
Variable; reduced by food, calcium, iron, PPIs'"`UNIQ--ref-0000001B-QINU`"' (1)
pregnancy:
First-line in pregnancy; dose typically increased 25-30% due to estrogen-driven rise in TBG and fetal demand. Lactation safe at physiologic doses.<sup class="pcp-cn" title="This claim needs a citation.">[[[Pharmacopedia:Citation needed|citation needed]]]</sup> (1) ·
Limited human data; some signal for cardiac malformations and developmental delay but confounded by maternal disease and polytherapy.<sup class="pcp-cn" title="This claim needs a citation.">[[[Pharmacopedia:Citation needed|citation needed]]]</sup> (1) ·
Synthetic levothyroxine is the standard-of-care in pregnancy; desiccated thyroid use in pregnancy is not well studied.'"`UNIQ--ref-0000001C-QINU`"' (1)
Showing below up to 3 results in range #1 to #3.