Drilldown: Medicines

Dextromethorphan / Quinidine (1) · Lovastatin (1) · Pravastatin (1) · Simvastatin (1)

Altoprev (ER), Mevacor (discontinued US); mostly generic (1) · Nuedexta (1) · Pravachol (1) · Zocor (1)

None (1) · [[:Category:Lipid-lowering_agents|Lipid-lowering agent]] (3) · [[:Category:Statins|Statin]] (3)

None (2) · '"`UNIQ--vote-000003D1-QINU`"' SLCO1B1 polymorphism affects exposure but is most clinically actionable for simvastatin'"`UNIQ--ref-000003D2-QINU`"'. (1) · '"`UNIQ--vote-00001580-QINU`"' First FDA-approved treatment for PBA. The 10 mg quinidine daily dose is far below antiarrhythmic levels but sufficient to nearly fully inhibit CYP2D6, the basis of the combination's pharmacokinetic rationale'"`UNIQ--ref-00001581-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) · '"`UNIQ--vote-00001582-QINU`"' (1)

1 capsule (20/10 mg dextromethorphan/quinidine) PO once daily × 7 days, then 1 capsule BID (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) · 20 mg dextromethorphan HBr / 10 mg quinidine sulfate capsules (1) · 5, 10, 20, 40, 80 mg tablets; 4 mg/mL oral suspension (1)

1 capsule BID (40 mg DXM / 20 mg quinidine per day) (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)

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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12 hours (1) · 24 hours (2) · 24 hours (evening dosing aligns with overnight HMG-CoA reductase peak) (1)

Dextromethorphan substantially prolonged by quinidine's CYP2D6 inhibition (typical extensive metabolizers see ~10× higher AUC); quinidine ~6-8 hours'"`UNIQ--ref-00001583-QINU`"' (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)

<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) · Increased substantially via CYP2D6 inhibition'"`UNIQ--ref-00001584-QINU`"' (1) · ~17% (oral; food slightly reduces absorption)'"`UNIQ--ref-000003D6-QINU`"' (1)

Limited data; quinidine has been used in pregnancy as antiarrhythmic.<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 (3) · [[USLegal:Prescription only|Rx-only]] in US. Caution with QT-prolonging medicines (quinidine itself is class IA antiarrhythmic, and the dose here, though sub-antiarrhythmic, still contributes to QT)'"`UNIQ--ref-00001585-QINU`"' (1)