Coco-Quinine Interactions
Effects of Drugs and Other Agents on Quinine Pharmacokinetics
Antacids: Antacids containing aluminum and/or magnesium may delay or decrease absorption of quinine. Concomitant administration of these antacids with quinine should be avoided.
Cholestyramine: In 8 healthy volunteers who received quinine sulfate 600 mg with or without 8 grams of cholestyramine resin, no significant difference in quinine pharmacokinetic parameters was seen.
Erythromycin (CYP3A4 inhibitor): Erythromycin was shown to inhibit the metabolism of quinine in vitro using human liver microsomes. Therefore, concomitant administration of erythromycin with quinine sulfate is likely to increase plasma quinine concentrations, and should be avoided.
Grapefruit juice (CYP3A4 inhibitor): In a pharmacokinetic study involving 10 healthy volunteers, the administration of a single 600 mg dose of quinine sulfate with grapefruit juice (full-strength or half-strength) did not significantly alter the pharmacokinetic parameters of quinine. Quinine sulfate may be taken with grapefruit juice.
Histamine H2-receptor blockers (cimetidine, ranitidine): In healthy volunteers who were given a single oral 600 mg dose of quinine sulfate after pretreatment with cimetidine (200 mg three times daily and 400 mg at bedtime for 7 days) or ranitidine (150 mg twice daily for 7 days), the apparent oral clearance of quinine decreased and the mean elimination half- life increased significantly when given with cimetidine but not with ranitidine. Compared to untreated controls, the mean AUC of quinine increased by only 20% with ranitidine and by 42% with cimetidine (p<0.05) without a significant change in mean quinine Cmax. When quinine is to be given concomitantly with a histamine H2 receptor blocker, the use of ranitidine is preferred over cimetidine. Although cimetidine may be used concomitantly with quinine sulfate, patients should be monitored closely for adverse events associated with quinine.
Isoniazid: Isoniazid 300 mg/day pretreatment for 1 week did not significantly alter the pharmacokinetic parameters of quinine. Adjustment of quinine dosage is not necessary when isoniazid is given concomitantly.
Ketoconazole (CYP3A4 inhibitor): In a crossover study, healthy subjects (N=9) who received a single oral dose of quinine hydrochloride (500 mg) concomitantly with ketoconazole (100 mg twice daily for 3 days) had a mean quinine AUC that was higher by 45% and a mean oral clearance of quinine that was 31% lower than after receiving quinine alone. Although no change in the quinine dosage regimen is necessary with concomitant ketoconazole, patients should be monitored closely for adverse reactio ns associated with quinine sulfate.
Oral contraceptives (estrogen, progestin): In 7 healthy females who were using single ingredient progestin or combination estrogen-containing oral contraceptives, the pharmacokinetic parameters of a single 600 mg dose of quinine sulfate were not altered in comparison to those observed in 7 age- matched female control subjects not using oral contraceptives.
Rifampin (CYP3A4 inducer): In patients with uncomplicated P. falciparum malaria who received quinine sulfate 10 mg/kg concomitantly with rifampin 15 mg/kg/day for 7 days (N=29), the median AUC of quinine between days 3 and 7 of therapy was 75% lower as compared to those who received quinine monotherapy. In healthy volunteers (N=9) who received a single oral 600 mg dose of quinine sulfate after 2 weeks of pretreatment with rifampin 600 mg/day, the mean quinine AUC and C max decreased by 85% and 55%, respectively. Therefore the concomitant administration of rifampin with quinine sulfate should be avoided .
Tetracycline: In 8 patients with acute uncomplicated P. falciparum malaria who were treated with oral quinine sulfate (600 mg every 8 hours for 7 days) in combination with oral tetracycline (250 mg every 6 hours for 7 days), the mean plasma quinine concentrations were about two- fold higher than in 8 patients who received quinine monotherapy. Although tetracycline may be concomitantly administered with quinine sulfate, patients should be monitored closely for adverse reactions associated with quinine sulfate.
Troleandomycin (CYP3A4 inhibitor): In a crossover study (N=10), healthy subjects who received a single oral 600 mg dose of quinine sulfate with the macrolide antibiotic, troleandomycin (500 mg every 8 hours) exhibited a 87% higher mean quinine AUC, a 45% lower mean oral clearance of quinine, and a 81% lower formation clearance of the main metabolite, 3-hydroxyquinine, than when quinine was given alone. Therefore, concomitant administration of troleandomycin with quinine sulfate should be avoided.
Urinary alkalizers (acetazolamide, sodium bicarbonate): Urinary alkalinizing agents may increase plasma quinine concentrations.
Effect of Quinine on the Pharmacokinetics of Other Drugs
Results of in vivo and in vitro drug interaction studies suggest that quinine has the potential to inhibit the metabolism of drugs that are substrates of CYP3A4 and CYP2D6, as well as inhibit the biliary excretion of drugs like digoxin.
Anticonvulsants (carbamazepine, phenobarbital, and phenytoin): A single 600 mg oral dose of quinine sulfate increased the mean plasma C max, and AUC0-24 of single oral doses of carbamazepine (200 mg) and phenobarbital (120 mg) but not phenytoin (200 mg) in 8 healthy subjects. The mean AUC increases of carbamazepine, phenobarbital and phenytoin were 104%, 81% and 4%, respectively; the mean increases in C max were 56%, 53%, and 4%, respectively. Mean urinary recoveries of the three antiepileptics over 24 hours were also profoundly increased by quinine. If concomitant administration with carbamazepine or phenobarbital cannot be avoided, frequent monitoring of anticonvulsant drug concentrations is recommended. Additionally, patients should be monitored closely for adverse reactions associated with these anticonvulsants. Carbamazepine, phe nobarbital, and phenytoin are CYP3A4 inducers and may decrease quinine plasma concentrations if used concurrently with quinine sulfate.
Astemizole (CYP3A4 substrate): Elevated plasma astemizole concentrations were reported in a subject who experienced torsades de pointes after receiving three doses of quinine sulfate for nocturnal leg cramps concomitantly with chronic astemizole 10 mg/day. The concurrent use of quinine with astemizole and other CYP3A4 substrates with QT prolongation potential (e.g., cisapride, terfenadine, halofantrine, pimozide, and quinidine ) should also be avoided
Desipramine (CYP2D6 substrate): Quinine (750 mg/day for 2 days) decreased the metabolism of desipramine in patients who were extensive CYP2D6 metabolizers, but had no effect in patients who were poor CYP2D6 metabolizers. Lower doses (80 mg to 400 mg) of quinine did not significantly affect the pharmacokinetics of other CYP2D6 substrates, namely, debrisoquine, dextromethorphan, and methoxyphenamine. Although clinical drug interaction studies have not been performed, antimalarial doses (greater than or equal to 600 mg) of quinine may inhibit the metabolism of other drugs that are CYP2D6 substrates (e.g., flecainide, debrisoquine, dextromethorphan, metoprolol, paroxetine ). Patients taking medications that are CYP2D6 substrates with quinine sulfate should be monitored closely for adverse reactions a sociated with these medications.
Digoxin: In 4 healthy subjects who received digoxin (0.5 to 0.75 mg/day) during treatment with quinine (750 mg/day), a 33% increase in mean steady state AUC of digoxin and a 35% reduction in the steady-state biliary clearance of digoxin were observed compared to digoxin alone. Thus, if quinine is administered to patients receiving digo xin, plasma digoxin concentrations should be closely monitored, and the digoxin dose adjusted, as necessary.
Halofantrine: Although not studied clinically, quinine was shown to inhibit the metabolism of halofantrine in vitro using human liver microsomes. Therefore, concomitant administration of quinine sulfate is likely to increase plasma halofantrine concentrations.
Mefloquine: In 7 healthy subjects who received mefloquine (750 mg) at 24 hours before an oral 600 mg dose of quinine sulfate, the AUC of mefloquine was increased by 22% compared to mefloquine alone. In this study, the QTc interval was significantly prolonged in the subjects who received mefloquine and quinine sulfate 24 hours apart. The concomitant administration of mefloquine and quinine may produce electrocardiographic abnormalities (including QTc prolongation) and may increase the risk of seizures.
Neuromuscular blocking agents (pancuronium, succinylcholine, tubocurarine): In one report, quinine potentiated neuromuscular blockade in a patient who received pancuronium during an operative procedure, and subsequently (3 hours after receiving pancuronium) received quinine 1800 mg daily. Quinine may also enhance the neuromuscular blocking effects of succinylcholine and tubocurarine .
Warfarin and oral anticoagulants: Cinchona alkaloids, including quinine, may have the potential to depress hepatic enzyme synthesis of vitamin K-dependent coagulation pathway proteins and may enhance the action of warfarin and other oral anticoagulants. Quinine may also interfere with the anticoagulant effect of heparin. Thus, in patients receiving these anticoagulants, the prothrombin time (PT), partial thromboplastin time (PTT), or international normalization ratio (INR) should be closely monitored as appropriate, during concurrent therapy with quinine.
Drug/Laboratory Interactions: Quinine may produce an elevated value for urinary 17-ketogenic steroids when the Zimmerman method is used.
Coco-Quinine Contraindications
Quinine is contraindicated in patients with known hypersensitivity, in pregnancy, in women of child bearing potential, in patients with glucose-6-phosphate dehydrogenase deficiency, in patients with tinnitus, or optic neuritis, and in patients with a history of blackwater fever.
Additional information about Coco-Quinine
Coco-Quinine Indication: For the treatment of malaria and leg crampsMechanism Of Action: The theorized mechanism of action for quinine and related anti-malarial drugs is that these drugs are toxic to the malaria parasite. Specifically, the drugs interfere with the parasite's ability to break down and digest hemoglobin. Consequently, the parasite starves and/or builds up toxic levels of partially degraded hemoglobin in itself.
Drug Interactions: Anisindione Coco-Quinine/quinidine increases the anticoagulant effect
Acenocoumarol Coco-Quinine/quinidine increases the anticoagulant effect
Dicumarol Coco-Quinine/quinidine increases the anticoagulant effect
Warfarin Coco-Quinine/quinidine increases the anticoagulant effect
Digoxin Coco-Quinine/quinidine increases the effect of digoxin
Digitoxin Coco-Quinine/quinidine increases the effect of digoxin
Vecuronium The quinine derivative increases the effect of the muscle relaxant
Succinylcholine The quinine derivative increases the effect of the muscle relaxant
Pancuronium The quinine derivative increases the effect of the muscle relaxant
Metocurine The quinine derivative increases the effect of the muscle relaxant
Gallamine Triethiodide The quinine derivative increases the effect of the muscle relaxant
Atracurium The quinine derivative increases the effect of the muscle relaxant
Astemizole Increased risk of cardiotoxicity and arrhythmias
Atomoxetine The CYP2D6 inhibitor could increase the effect and toxicity of atomoxetine
Mesoridazine Increased risk of cardiotoxicity and arrhythmias
Thioridazine Increased risk of cardiotoxicity and arrhythmias
Terfenadine Increased risk of cardiotoxicity and arrhythmias
Food Interactions: Not Available
Generic Name: Quinine
Synonyms: 6'-Methoxycinchonidine; 6'-Methoxycinchonine; Quinine, Anhydrous; Quinineanhydrous; Quinoline Alkaloid; Quinine sulfate
Where to order Quinine (and Coco-Quinine analogs) online:
Drug Category: Analgesics, Non-Narcotic; Muscle Relaxants, Central; Antimalarials
Drug Type: Small Molecule; Approved
Other Brand Names containing Quinine: Aflukin; Chinin; Chinine; Coco-Quinine; None; Quinine Dab;
Absorption: 76 - 88%
Toxicity (Overdose): Not Available
Protein Binding: Approximately 70%
Biotransformation: Hepatic, over 80% metabolized by the liver.
Half Life: Approximately 18 hours
Dosage Forms of Coco-Quinine: Solution / drops Oral
Tablet Oral
Liquid Oral
Capsule Oral
Chemical IUPAC Name: (R)-[(5R,7S)-5-ethenyl-1-azabicyclo[2.2.2]octan-7-yl]-(6-methoxyquinolin-4-yl)methanol
Chemical Formula: C20H24N2O2
Quinine on Wikipedia: http://en.wikipedia.org/wiki/Quinine
Organisms Affected: Humans and other mammals
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