Drilldown: Medicines
Medicines > fda max 
:
No fixed maximum; titrated to TSH target or
No strict ceiling; water-soluble vitamin, low toxicity
:
No fixed maximum; titrated to TSH target or
No strict ceiling; water-soluble vitamin, low toxicity Use the filters below to narrow your results.
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-00000033-QINU`"', '"`UNIQ--vote-00000034-QINU`"', '"`UNIQ--vote-00000035-QINU`"' (1) ·
'"`UNIQ--vote-00000607-QINU`"', '"`UNIQ--vote-00000608-QINU`"', '"`UNIQ--vote-00000609-QINU`"', '"`UNIQ--vote-0000060A-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) ·
Replacement: 1000 mcg IM daily for 1 week, then weekly for 4 weeks, then monthly; or 1000-2000 mcg PO daily (effective even in pernicious anemia via passive diffusion); intranasal 500 mcg weekly (1)
preparations:
100, 250, 500, 1000, 5000 mcg tablets (OTC and Rx); 1000 mcg/mL injection; intranasal spray; sublingual (1) ·
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)
fda max: (Click arrow to add another value)
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onset:
duration:
halflife:
bioavailability:
40-80% (oral); reduced by food, calcium, iron, PPIs, fiber; take fasting with water'"`UNIQ--ref-00000037-QINU`"' (1) ·
Oral ~1-3% via passive diffusion at high doses (independent of intrinsic factor); IM/SC ~100% (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) ·
Routinely supplemented in vegan pregnancies and pernicious anemia.<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.