Drilldown: Medicines

Levothyroxine (1) · Lovastatin (1) · Pravastatin (1) · Simvastatin (1)

Altoprev (ER), Mevacor (discontinued US); mostly generic (1) · Pravachol (1) · Synthroid, Levoxyl, Tirosint, Unithroid, Euthyrox (1) · Zocor (1)

[[:Category:Hormone_replacement|Hormone replacement]] (1) · [[:Category:Lipid-lowering_agents|Lipid-lowering agent]] (3) · [[:Category:Statins|Statin]] (3) · [[:Category:Thyroid_hormones|Thyroid hormone]] (1)

None (2) · 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-000003D1-QINU`"' SLCO1B1 polymorphism affects exposure but is most clinically actionable for simvastatin'"`UNIQ--ref-000003D2-QINU`"'. (1)

'"`UNIQ--vote-00000033-QINU`"', '"`UNIQ--vote-00000034-QINU`"', '"`UNIQ--vote-00000035-QINU`"' (1) · '"`UNIQ--vote-00000178-QINU`"', '"`UNIQ--vote-00000179-QINU`"' (1) · '"`UNIQ--vote-000003D3-QINU`"', '"`UNIQ--vote-000003D4-QINU`"' (1) · '"`UNIQ--vote-00000805-QINU`"', '"`UNIQ--vote-00000806-QINU`"' (1)

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) · 10-20 mg PO once daily in the evening (40 mg starting allowed for high CV risk) (1) · 20 mg PO once daily with the evening meal; titrate to 40-80 mg/d (1) · 40 mg PO once daily (10-20 mg in elderly, hepatic impairment, or strong drug interactions) (1)

10 mg, 20 mg, 40 mg, 80 mg tablets (1) · 10, 20, 40 mg tablets; 20, 40, 60 mg ER tablets (1) · 25, 50, 75, 88, 100, 112, 125, 137, 150, 175, 200, 300 mcg tablets; oral capsule and IV/IM also available (1) · 5, 10, 20, 40, 80 mg tablets; 4 mg/mL oral suspension (1)

40 mg/d standard; 80 mg/d restricted to patients tolerating 80 mg for ≥12 months without myopathy (post-SEARCH 2011 FDA restriction) (1) · 80 mg/d (1) · 80 mg/d (40 mg/d if combined with diltiazem, verapamil, danazol; lower limits with various interactions) (1) · No fixed maximum; titrated to TSH target (1)

IV (1) · Oral (4)

None · Hours · 30-60 minutes · 1-2 hours · ~30 min · LDL lowering at 2 weeks, max by 4 weeks · ~1 hour · 15-30 minutes · 15–30 min · 1–2 h · 30–60 min · Antidepressant effect emerges over 1-2 weeks · BP and symptomatic LUTS improvement within 1-2 weeks · BP effect within 1-2 weeks · Clinical improvement within 24-72 hours · Days · Motor improvement over days at therapeutic dose · Over weeks · Postprandial glucose effect within days; HbA1c by 12 weeks · Sleep effect from first dose; antidepressant effect over 1-4 weeks

Other values:

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24 hours (2) · 24 hours (evening dosing aligns with overnight HMG-CoA reductase peak) (1) · Steady-state at 4-6 weeks (1)

~2 hours (parent and active β-hydroxy acid metabolite); pharmacodynamic effect lasts 24 hours via target turnover'"`UNIQ--ref-0000017A-QINU`"' (1) · ~2-3 hours (parent); pharmacodynamic effect 24 hours via target turnover'"`UNIQ--ref-000003D5-QINU`"' (1) · ~2-4 hours (parent and active β-hydroxy acid metabolite); pharmacodynamic effect 24 hours via target turnover'"`UNIQ--ref-00000807-QINU`"' (1) · ~7 days (euthyroid); longer in hypothyroidism (~9-10 days), shorter in hyperthyroidism'"`UNIQ--ref-00000036-QINU`"' (1)

40-80% (oral); reduced by food, calcium, iron, PPIs, fiber; take fasting with water'"`UNIQ--ref-00000037-QINU`"' (1) · <5% (extensive hepatic first-pass; food enhances absorption of IR, hence the evening-meal dosing)'"`UNIQ--ref-00000808-QINU`"' (1) · <5% (extensive hepatic first-pass; statin pharmacology is hepatocellular, not systemic)'"`UNIQ--ref-0000017B-QINU`"' (1) · ~17% (oral; food slightly reduces absorption)'"`UNIQ--ref-000003D6-QINU`"' (1)

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.">&#91;[[Pharmacopedia:Citation needed|citation&nbsp;needed]]&#93;</sup> (1) · Previously Category X; FDA removed the blanket statin contraindication in pregnancy in 2021.<sup class="pcp-cn" title="This claim needs a citation.">&#91;[[Pharmacopedia:Citation needed|citation&nbsp;needed]]&#93;</sup> (3)

[[USLegal:Prescription only|Rx-only]] in US (4)