QUALAQUIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for QUALAQUIN (QUALAQUIN).
Quinine is a cinchona alkaloid that acts as a blood schizonticide against Plasmodium species. It inhibits heme polymerase in the parasite, leading to accumulation of toxic heme and parasite death. It also has weak gametocytocidal activity against P. vivax and P. malariae.
| Metabolism | Primarily hepatic via CYP3A4. Metabolites include 3-hydroxyquinine (active) and others. About 20% excreted unchanged in urine. |
| Excretion | Renal (approximately 20% unchanged; remainder as metabolites); biliary/fecal (minor). |
| Half-life | Terminal elimination half-life approximately 8 hours in healthy adults; prolonged in hepatic impairment (up to 12-18 hours) and severe malaria (up to 14-20 hours). |
| Protein binding | ~90% bound to plasma proteins, primarily albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | Vd approximately 2-4 L/kg, indicating extensive tissue distribution (e.g., erythrocytes, liver, lungs). |
| Bioavailability | Oral: approximately 80% (well-absorbed; first-pass metabolism reduces systemic availability). |
| Onset of Action | Oral: rapid absorption; clinical antimalarial effect evident within 1-2 hours. Intravenous: antimalarial effect within 30 minutes. |
| Duration of Action | Oral: therapeutic plasma concentrations maintained for 6-8 hours; IV: effective for 4-6 hours post-dose. |
325-650 mg orally every 6 hours as needed for pain; maximum 2.6 g/day.
| Dosage form | CAPSULE |
| Renal impairment | No specific adjustment required for mild-moderate impairment. For CrCl <10 mL/min, maximum dose 650 mg every 12 hours. |
| Liver impairment | Child-Pugh A: no adjustment. Child-Pugh B or C: maximum 1.3 g/day with caution. |
| Pediatric use | 10-15 mg/kg/dose orally every 4-6 hours as needed; maximum 60 mg/kg/day. |
| Geriatric use | Start at lowest effective dose; maximum 2 g/day due to decreased clearance. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for QUALAQUIN (QUALAQUIN).
| Breastfeeding | Excreted in breast milk; M/P ratio not established. Avoid breastfeeding or discontinue drug due to potential adverse effects in infant. |
| Teratogenic Risk | First trimester: Avoid due to potential fetal toxicity. Second and third trimesters: Limited data; consider risks vs benefits. Animal studies show fetal harm at high doses. |
| Fetal Monitoring | Monitor maternal liver function, CBC, and fetal ultrasound for growth and development. Assess for signs of hemolysis or arrhythmia in mother. |
■ FDA Black Box Warning
Quinidine (related compound) has a boxed warning for increased mortality in treatment of atrial fibrillation/flutter. Quinine products have a boxed warning against use for leg cramps due to risk of serious adverse events including thrombocytopenia and cardiotoxicity.
| Serious Effects |
Hypersensitivity to quinine or cinchona derivatives, previous quinine-induced thrombocytopenia, prolonged QT interval, concurrent use of drugs that prolong QT interval, myasthenia gravis, optic neuritis, G6PD deficiency (relative; caution required), pregnancy (except for malaria treatment when no alternatives).
| Precautions | Cardiotoxicity (QT prolongation, arrhythmias), cinchonism (tinnitus, headache, visual disturbances), hypoglycemia, thrombocytopenia (immune-mediated), hemolytic-uremic syndrome/thrombotic thrombocytopenic purpura, hypersensitivity reactions, bronchospasm, and severe cutaneous adverse reactions. |
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| Fertility Effects | No specific human data; animal studies show no significant impact on fertility. Theoretical risk of impaired spermatogenesis or ovulation due to antimalarial effects. |