Note: Dosage expressed in terms of the salt; 1 capsule Quinoctal = 324 mg of Quinoctal = 269 mg of base; Canadian products contain 200 mg of Quinoctal = 167 mg of base or 300 mg of Quinoctal = 250 mg of base.

Malaria, uncomplicated, due to chloroquine-resistant P. falciparum (treatment):

Oral:

CDC guidelines: 648 mg every 8 hours, in combination with doxycycline, tetracycline, or clindamycin (preferred in pregnancy). Note: Administer Quinoctal for 3 days unless the infection was acquired in Southeast Asia, in which case Quinoctal duration of therapy is 7 days. Duration of concomitant agent is 7 days, regardless of geographic region (CDC 2013).

Canadian product: 600 mg every 8 hours for 3 to 7 days. Note: Use in combination with tetracycline, doxycycline, or clindamycin.

Malaria, uncomplicated, due to chloroquine-resistant P. vivax (treatment) (off-label use):

Oral: 648 mg every 8 hours, in combination with doxycycline or tetracycline plus primaquine. Note: Quinoctal in combination with clindamycin is an alternative regimen for pregnant patients. Administer Quinoctal for 3 days unless the infection was acquired in Southeast Asia, in which case Quinoctal duration of therapy is 7 days. Duration of concomitant agent is 7 days (doxycycline, tetracycline, clindamycin) or 14 days (primaquine), regardless of geographic region (CDC 2013).

Babesiosis (off-label use):

Oral: 650 mg every 6 to 8 hours for at least 7 to 10 days with clindamycin (Vannier 2012; Wormser 2006). Relapsing infection may require at least 6 weeks of therapy (Vannier 2012). Note: US manufactured Quinoctal capsule is 324 mg; 2 capsules (648 mg Quinoctal) should be sufficient for adult dosing.

Dosing: Geriatric

Refer to adult dosing.

Dosing: Pediatric

Note: Dosage expressed in terms of the Quinoctal salt; 324 mg capsule Quinoctal = 269 mg of base. Canadian products: 200 mg capsule of Quinoctal = 167 mg of base or 300 mg capsule of Quinoctal = 250 mg of base.

Malaria: Children and Adolescents; regardless of HIV status (HHS [OI pediatric 2013]): Limited data available in ages <16 years: Note: Duration of Quinoctal treatment for malaria dependent upon the geographic region or pathogen. Lack of an appropriate Quinoctal dosage form may restrict use in some smaller patients.

P. falciparum (chloroquine resistant), uncomplicated; treatment:

Oral: 10 mg/kg/dose Quinoctal every 8 hours for 3 to 7 days depending on region; maximum dose: 650 mg/dose; use in combination with tetracycline, doxycycline, or clindamycin (dependent upon patient age) (CDC 2013)

P. vivax (chloroquine resistant), uncomplicated; treatment:

Oral: 10 mg/kg/dose Quinoctal every 8 hours for 3 to 7 days depending on region; maximum dose: 650 mg/dose; use in combination with primaquine and tetracycline or doxycycline (dependent upon patient age) (CDC 2013)

Severe malaria:

Oral Quinoctal, using the regimens previously described (dose and duration), may be used following IV quinidine including antimicrobial regimen once parasite density is <1% and patient is able to tolerate oral medications (CDC 2013)

Babesiosis: Limited data available: Children and Adolescents:

Oral: 10 mg/kg/dose Quinoctal every 8 hours for 7 to 10 days; maximum dose: 650 mg/dose (Red Book [AAP 2015]; Wittner 1982); use in combination with clindamycin as a first-line treatment option (IDSA [Wormser 2006])

What other drugs will affect Quinoctal?

Many drugs can interact with Quinoctal. Not all possible interactions are listed here. Tell your doctor about all your medications and any you start or stop using during treatment with Quinoctal, especially:

acetazolamide, sodium bicarbonate;
aminophylline, theophylline;
arsenic trioxide, vandetanib;
bosentan;
imatinib;
methadone;
tacrolimus;
St. John's wort;
an antibiotic--azithromycin, clarithromycin, erythromycin, levofloxacin, moxifloxacin, pentamidine, telithromycin, tetracycline;
an antidepressant--amitriptyline, citalopram, clomipramine, desipramine, nefazodone, venlafaxine;
antifungal medication--itraconazole, ketoconazole, posaconazole, voriconazole;
cholesterol-lowering medicine--atorvastatin, simvastatin, lovastatin;
cough medicine that contains dextromethorphan;
heart medication--amiodarone, digoxin, dofetilide, disopyramide, dronedarone, flecainide, ibutilide, metoprolol, procainamide, propafenone, quinidine, sotalol, verapamil;
hepatitis C medications--boceprevir, telaprevir;
HIV/AIDS medication--atazanavir, delavirdine, efavirenz, fosamprenavir, indinavir, nelfinavir, nevirapine, ritonavir, saquinavir;
medicine to prevent or treat nausea and vomiting--dolasetron, droperidol, ondansetron;
medicine to treat a psychiatric disorder--chlorpromazine, clozapine, haloperidol, mesoridazine, pimozide, thioridazine, ziprasidone;
seizure medication--carbamazepine, fosphenytoin, oxcarbazepine, phenobarbital, phenytoin, primidone;
stomach acid reducers--cimetidine, ranitidine; or
tuberculosis medication--rifabutin, rifampin, rifapentine.

This list is not complete and many other drugs can interact with Quinoctal. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Give a list of all your medicines to any healthcare provider who treats you.

Quinoctal interactions

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Effects Of Drugs And Other Substances On Quinoctal Pharmacokinetics

Quinoctal is a P-gp substrate and is primarily metabolized by CYP3A4. Other enzymes, including CYP1A2, CYP2C8, CYP2C9, CYP2C19, CYP2D6, and CYP2E1 may contribute to the metabolism of Quinoctal.

Antacids

Antacids containing aluminum and/or magnesium may delay or decrease absorption of Quinoctal. Concomitant administration of these antacids with Quinoctal should be avoided.

Antiepileptics (AEDs) (carbamazepine, phenobarbital, and phenytoin)

Carbamazepine, phenobarbital, and phenytoin are CYP3A4 inducers and may decrease Quinoctal plasma concentrations if used concurrently with Quinoctal.

Cholestyramine

In 8 healthy subjects who received Quinoctal 600 mg with or without 8 grams of cholestyramine resin, no significant difference in Quinoctal pharmacokinetic parameters was seen.

Cigarette Smoking (CYP1A2 inducer)

In healthy male heavy smokers, the mean Quinoctal AUC following a single 600 mg dose was 44% lower, the mean Cmax was 18% lower, and the elimination half-life was shorter (7.5 hours versus 12 hours) than in their non-smoking counterparts. However, in malaria patients who received the full 7-day course of Quinoctal therapy, cigarette smoking produced only a 25% decrease in median Quinoctal AUC and a 16.5% decrease in median Cmax, suggesting that the already reduced clearance of Quinoctal in acute malaria could have diminished the metabolic induction effect of smoking. Because smoking did not appear to influence the therapeutic outcome in malaria patients, it is not necessary to increase the dose of Quinoctal in the treatment of acute malaria in heavy cigarette smokers.

Grapefruit juice (P-gp/CYP3A4 inhibitor)

In a pharmacokinetic study involving 10 healthy subjects, the administration of a single 600 mg dose of Quinoctal with grapefruit juice (full-strength or half-strength) did not significantly alter the pharmacokinetic parameters of Quinoctal. Quinoctal may be taken with grapefruit juice.

Histamine H2-receptor blockers [cimetidine, ranitidine (nonspecific CYP450 inhibitors)]

In healthy subjects who were given a single oral 600 mg dose of Quinoctal 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 Quinoctal 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 Quinoctal increased by 20% with ranitidine and by 42% with cimetidine (p < 0.05) without a significant change in mean Quinoctal Cmax. When Quinoctal is to be given concomitantly with a histamine H2-receptor blocker, the use of ranitidine is preferred over cimetidine. Although cimetidine and ranitidine may be used concomitantly with Quinoctal, patients should be monitored closely for adverse events associated with Quinoctal.

Isoniazid

Isoniazid 300 mg/day pretreatment for 1 week did not significantly alter the pharmacokinetic parameter values of Quinoctal. Adjustment of Quinoctal 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 Quinoctal hydrochloride (500 mg) concomitantly with ketoconazole (100 mg twice daily for 3 days) had a mean Quinoctal AUC that was higher by 45% and a mean oral clearance of Quinoctal that was 31% lower than after receiving Quinoctal alone. Although no change in the Quinoctal dosage regimen is necessary with concomitant ketoconazole, patients should be monitored closely for adverse reactions associated with Quinoctal.

Macrolide Antibiotics (erythromycin, troleandomycin) (CYP3A4 inhibitors)

In a crossover study (N=10), healthy subjects who received a single oral 600 mg dose of Quinoctal with the macrolide antibiotic, troleandomycin (500 mg every 8 hours) exhibited a 87% higher mean Quinoctal AUC, a 45% lower mean oral clearance of Quinoctal, and a 81% lower formation clearance of the main metabolite, 3-hydroxyquinine, than when Quinoctal was given alone.

Erythromycin was shown to inhibit the in vitro metabolism of Quinoctal in human liver microsomes, an observation confirmed by an in vivo interaction study. In a crossover study (N=10), healthy subjects who received a single oral 500 mg dose of Quinoctal with erythromycin (600 mg every 8 hours for four days) showed a decrease in Quinoctal oral clearance (CL/F), an increase in half-life, and a decreased metabolite (3hydroxyquinine) to Quinoctal AUC ratio, as compared to when Quinoctal was given with placebo.

Therefore, concomitant administration of macrolide antibiotics such as erythromycin or troleandomycin with Quinoctal should be avoided.

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 Quinoctal 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 Quinoctal 10 mg/kg concomitantly with rifampin 15 mg/kg/day for 7 days (N=29), the median AUC of Quinoctal between days 3 and 7 of therapy was 75% lower as compared to those who received Quinoctal monotherapy. In healthy subjects (N=9) who received a single oral 600 mg dose of Quinoctal after 2 weeks of pretreatment with rifampin 600 mg/day, the mean Quinoctal AUC and Cmax decreased by 85% and 55%, respectively. Therefore, the concomitant administration of rifampin with Quinoctal should be avoided.

Ritonavir

In healthy subjects who received a single oral 600 mg dose of Quinoctal with the 15 dose of ritonavir (200 mg every 12 hours for 9 days), the mean ritonavir AUC, Cmax, and elimination half-life were slightly but not significantly increased compared to when ritonavir was given alone. However, due to the significant effect of ritonavir on Quinoctal pharmacokinetics, the concomitant administration of Quinoctal capsules with ritonavir should be avoided.

Theophylline Or Aminophylline (CYP1A2 substrate)

In 19 healthy subjects who received multiple doses of Quinoctal 648 mg every 8 hours x 7 days with a single 300 mg oral dose of theophylline, the mean theophylline AUC was 10% lower than when theophylline was given alone. There was no significant effect on mean theophylline Cmax. Therefore, if Quinoctal is co-administered to patients receiving theophylline or aminophylline, plasma theophylline concentrations should be monitored frequently to ensure therapeutic concentrations.

Warfarin And

Oral Anticoagulants

Cinchona alkaloids, including Quinoctal, 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. Quinoctal 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 Quinoctal.

Drug/Laboratory Interactions

Quinoctal may produce an elevated value for urinary 17-ketogenic steroids when the Zimmerman method is used.

Quinoctal may interfere with urine qualitative dipstick protein assays as well as quantitative methods (e.g., pyrogallol red-molybdate).

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References

DailyMed. "QUININE SULFATE: DailyMed provides trustworthy information about marketed drugs in the United States. DailyMed is the official provider of FDA label information (package inserts).". https://dailymed.nlm.nih.gov/dailyme... (accessed September 17, 2018).
FDA/SPL Indexing Data. "A7V27PHC7A: The UNique Ingredient Identifier (UNII) is an alphanumeric substance identifier from the joint FDA/USP Substance Registration System (SRS).". https://www.fda.gov/ForIndustry/Data... (accessed September 17, 2018).
MeSH. "Analgesics, Non-Narcotic". https://www.ncbi.nlm.nih.gov/mesh/68... (accessed September 17, 2018).

Reviews

The results of a survey conducted on ndrugs.com for Quinoctal are given in detail below. The results of the survey conducted are based on the impressions and views of the website users and consumers taking Quinoctal. We implore you to kindly base your medical condition or therapeutic choices on the result or test conducted by a physician or licensed medical practitioners.

User reports

Consumer reported frequency of use

No survey data has been collected yet

Consumer reported doses