QUINORA

Clinical safety rating: caution

Comprehensive clinical and safety monograph for QUINORA (QUINORA).

How it works

Quinora (quinidine) is a Class Ia antiarrhythmic agent that blocks sodium channels, prolonging the action potential duration and effective refractory period. It also exhibits anticholinergic and negative inotropic effects.

What the body does with it

Metabolism	Primarily hepatic via CYP3A4; also metabolized by CYP2C9 and CYP2E1. Active metabolites include 3-hydroxyquinidine. Renal excretion of unchanged drug accounts for 10-20% of clearance.
Excretion	Primarily hepatic (biliary) excretion into feces (~80-90%); renal excretion of unchanged drug accounts for ~10-20%.
Half-life	5-7 hours; prolonged in hepatic impairment (up to 12-15 hours) and in elderly patients.
Protein binding	90-95% bound to plasma proteins (primarily albumin and alpha-1-acid glycoprotein).
Volume of Distribution	2.5-3.5 L/kg; extensive tissue distribution with high affinity for cardiac muscle.
Bioavailability	Oral: ~70-80% (first-pass metabolism reduces bioavailability; food may decrease rate but not extent).
Onset of Action	Oral: 30-60 minutes; IV: within 5 minutes.
Duration of Action	6-8 hours after single dose; may extend with repeated dosing due to accumulation.

Classification & Brands

Dosing & administration

325 mg orally every 4 to 6 hours as needed, not to exceed 4 g/day.

Dosage form	TABLET
Renal impairment	GFR 30-50 mL/min: reduce dose by 25%; GFR <30 mL/min: avoid use or prolong dosing interval to every 8 hours.
Liver impairment	Child-Pugh Class A: no adjustment; Child-Pugh Class B: reduce dose by 50%; Child-Pugh Class C: avoid use.
Pediatric use	10-15 mg/kg/dose orally every 4-6 hours; maximum 60 mg/kg/day.
Geriatric use	Start at lowest effective dose; consider 325 mg every 6-8 hours due to increased risk of accumulation.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for QUINORA (QUINORA).

Breastfeeding	Excreted into breast milk; M/P ratio unknown. Due to risk of serious adverse reactions in nursing infants including kernicterus in neonates with G6PD deficiency, contraindicated during breastfeeding.
Teratogenic Risk	In first trimester, associated with increased risk of spontaneous abortion and congenital anomalies including cardiovascular and neural tube defects. Second and third trimester exposure may cause premature closure of ductus arteriosus, oligohydramnios, and neonatal renal impairment.
Fetal Monitoring

Warnings & precautions

■ FDA Black Box Warning

May cause potentially fatal ventricular arrhythmias (e.g., torsades de pointes) due to QT prolongation. Reserve for patients with life-threatening arrhythmias. Monitor ECG and serum electrolytes. Discontinue if QT interval >50% baseline or QRS duration increases >25%.

Side Effect Profile

Serious Effects

Absolute Contraindications

History of QT prolongation or torsades de pointes with quinidine. Myasthenia gravis (due to anticholinergic effects). Complete AV block without pacemaker. Known hypersensitivity (including thrombocytopenia). Major contraindication in malaria caused by Plasmodium falciparum with severe adverse reactions.

Clinical Precautions

Precautions

May cause cinchonism (tinnitus, headache, visual disturbances). Risk of QT prolongation and torsades de pointes, especially in patients with hypokalemia, bradycardia, or structural heart disease. Hemolytic anemia may occur in G6PD deficiency. Can exacerbate heart failure due to negative inotropic effects. Drug interactions: hepatic enzyme inducers/inhibitors, other QT-prolonging drugs.

Clinical Tips & Counseling

Drug interactions

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QUINORA

Clinical safety rating: caution

Comprehensive clinical and safety monograph for QUINORA (QUINORA).

How it works

What the body does with it

Metabolism	Primarily hepatic via CYP3A4; also metabolized by CYP2C9 and CYP2E1. Active metabolites include 3-hydroxyquinidine. Renal excretion of unchanged drug accounts for 10-20% of clearance.
Excretion	Primarily hepatic (biliary) excretion into feces (~80-90%); renal excretion of unchanged drug accounts for ~10-20%.
Half-life	5-7 hours; prolonged in hepatic impairment (up to 12-15 hours) and in elderly patients.
Protein binding	90-95% bound to plasma proteins (primarily albumin and alpha-1-acid glycoprotein).
Volume of Distribution	2.5-3.5 L/kg; extensive tissue distribution with high affinity for cardiac muscle.
Bioavailability	Oral: ~70-80% (first-pass metabolism reduces bioavailability; food may decrease rate but not extent).
Onset of Action	Oral: 30-60 minutes; IV: within 5 minutes.
Duration of Action	6-8 hours after single dose; may extend with repeated dosing due to accumulation.

Classification & Brands

Dosing & administration

325 mg orally every 4 to 6 hours as needed, not to exceed 4 g/day.

Dosage form	TABLET
Renal impairment	GFR 30-50 mL/min: reduce dose by 25%; GFR <30 mL/min: avoid use or prolong dosing interval to every 8 hours.
Liver impairment	Child-Pugh Class A: no adjustment; Child-Pugh Class B: reduce dose by 50%; Child-Pugh Class C: avoid use.
Pediatric use	10-15 mg/kg/dose orally every 4-6 hours; maximum 60 mg/kg/day.
Geriatric use	Start at lowest effective dose; consider 325 mg every 6-8 hours due to increased risk of accumulation.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for QUINORA (QUINORA).

Breastfeeding	Excreted into breast milk; M/P ratio unknown. Due to risk of serious adverse reactions in nursing infants including kernicterus in neonates with G6PD deficiency, contraindicated during breastfeeding.
Teratogenic Risk	In first trimester, associated with increased risk of spontaneous abortion and congenital anomalies including cardiovascular and neural tube defects. Second and third trimester exposure may cause premature closure of ductus arteriosus, oligohydramnios, and neonatal renal impairment.
Fetal Monitoring