Quinine sulfate
Pronunciation: pronunciation varies by local usage.
- Generic name
- quinine sulfate
- Brand names
- QUALAQUIN
- Drug class
- Antimalarial
- Form
- Capsule
- Route
- Oral
- Legal status
- Prescription-only medicine
Availability and supply rules vary by country
Trade names by country: United States · Canada
Australia: · Full directory
What quinine sulfate is and how it works
Quinine sulfate is an antimalarial used for treatment of uncomplicated Plasmodium falciparum malaria. (1)
It is not approved for nocturnal leg cramps, which carries a boxed warning for serious and life-threatening hematologic reactions. Treatment is prescriber-managed.
Mechanism of action: how quinine sulfate works
Quinine sulfate is an antimalarial agent active against Plasmodium falciparum. (1)
What quinine sulfate is used for
Uncomplicated Plasmodium falciparum malaria
Quinine sulfate is indicated for the treatment of uncomplicated Plasmodium falciparum malaria in adults and children 16 years and older. It is not approved for prevention or treatment of nocturnal leg cramps. (1)
Before taking quinine sulfate
Do not take / not appropriate for
- Do not take quinine if you have a prolonged QT interval, G6PD deficiency, myasthenia gravis, optic neuritis, or known hypersensitivity to quinine, mefloquine, or quinidine (including prior blackwater fever or thrombotic thrombocytopenic purpura). (all indications) (1)
- Do not use quinine for nocturnal leg cramps because serious and life-threatening hematologic reactions have occurred. (off-label use) (1)
Tell your clinician about
- Any history of irregular heartbeat, G6PD deficiency, myasthenia gravis, or eye nerve problems.
- All current medications, especially other drugs that prolong the QT interval, digoxin, warfarin, rifampin, or antacids.
- If you are pregnant, planning pregnancy, or breastfeeding.
- Any symptoms of low blood sugar, unusual bruising, or ringing in the ears.
How to take quinine sulfate
- Take exactly as prescribed by your healthcare provider. The typical adult dose is 648 mg (two 324 mg capsules) every 8 hours for 7 days.
- Swallow the capsules whole with food or water to reduce stomach upset.
- Complete the entire 7-day course even if you start to feel better. Stopping early may result in incomplete treatment of the malaria infection.
Procedures and treatment changes
Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1)
Missed dose
Contact your healthcare provider for instructions if you miss a dose. Do not take an extra dose to make up for the missed one.
Overdose
Overdose may cause severe cinchonism (ringing in the ears, vision changes, headache, nausea), low blood sugar, or heart rhythm disturbance. Seek immediate medical attention or contact a poison control center. (1)
Side effects
Common side effects include cinchonism (headache, tinnitus, hearing loss, blurred vision). Serious hematologic and cardiac reactions can occur even at therapeutic doses.
Cinchonism-related symptoms
What to notice: Headache, sweating, nausea, tinnitus (ringing in the ears), hearing impairment, vertigo, dizziness, blurred vision, color-vision disturbance.
What to do: Tell your healthcare provider if these symptoms become severe or bothersome. (1)
Gastrointestinal effects
What to notice: Vomiting, diarrhea, abdominal pain.
What to do: Take with food and report persistent or severe symptoms to your healthcare provider. (1)
Unusual bleeding or bruising
What to notice: Easy bruising, bleeding gums, or heavy menstrual bleeding.
What to do: Contact your healthcare provider immediately; this may be a sign of low platelets (thrombocytopenia) including a serious condition called HUS/TTP. (1)
Heart rhythm changes
What to notice: Palpitations, feeling faint, or fainting.
What to do: Seek medical attention promptly; this could indicate QT prolongation which can lead to dangerous arrhythmias. (1)
Severe allergic or skin reactions
What to notice: Rash, blistering, or peeling skin, especially if accompanied by fever or mucous membrane involvement.
What to do: Report to your healthcare provider immediately; quinine can cause serious hypersensitivity including Stevens-Johnson syndrome. (1)
Low blood sugar (hypoglycemia)
What to notice: Sweating, shakiness, feeling weak, confused, or hungry.
What to do: Consume a quick source of sugar (like juice or glucose tablets) and contact your healthcare provider. (1)
Serious warnings
Hematologic reactions (thrombocytopenia, HUS/TTP) — emergency
Symptoms: Unexplained bruising, bleeding, severe headache, confusion, or changes in urine output.
Action: Seek emergency medical attention immediately. The clinician stops quinine and does not restart it. (1)
Serious cardiac arrhythmias (QT prolongation, torsades de pointes) — emergency
Symptoms: Fainting, palpitations, irregular heartbeat.
Action: Call emergency services or go to the nearest emergency department. (1)
Severe hypersensitivity reactions (anaphylaxis, Stevens-Johnson syndrome) — emergency
Symptoms: Difficulty breathing, swelling of face/throat, widespread blistering rash, or peeling skin.
Action: Call emergency services immediately and seek medical attention right away. (1)
Interactions
| Medicine or test | Effect | Action |
|---|---|---|
| Other QT-prolonging drugs (e.g., class IA/III antiarrhythmics, macrolides, mefloquine, halofantrine) | Increased risk of life-threatening cardiac arrhythmias. | Avoid combined use; inform your healthcare provider of all medications. (1) |
| Digoxin | Quinine may increase digoxin levels, risking toxicity. | Your healthcare provider may monitor digoxin levels and adjust the dose. (1) |
| Warfarin | Anticoagulant effect may be enhanced, increasing bleeding risk. | Your healthcare provider should monitor your clotting times closely. (1) |
| CYP3A4 inhibitors (e.g., ketoconazole, ritonavir) or inducers (e.g., rifampin, carbamazepine) | Inhibitors can increase quinine levels and toxicity; inducers can decrease levels causing treatment failure. | Inform your healthcare provider of all drugs; dose adjustments or alternative therapy may be needed. (1) |
| Antacids containing aluminum or magnesium | May reduce quinine absorption. | Space doses apart (take quinine at least 2 hours before or after antacids). (1) |
Pregnancy, breastfeeding, kidney/liver function, age
Children and adolescents
Quinine sulfate is not approved for use in children younger than 16 years. Safety and efficacy have not been established. (1)
Pregnancy
Published data on over 1,000 exposures have not shown increased teratogenic effects. However, untreated falciparum malaria in pregnancy is itself associated with serious risks. The decision to use quinine should be made by a healthcare provider. (1)
Breastfeeding
Infant exposure through breast milk is estimated below 2–3 mg per day, much lower than therapeutic doses. Discuss with your healthcare provider whether to continue breastfeeding during treatment. (1)
Severe renal impairment
The dose must be adjusted: a loading dose of 648 mg followed by 324 mg every 12 hours for 7 days, as determined by the prescribing physician. (1)
Hepatic impairment
No dose adjustment is needed for mild or moderate impairment, but close monitoring is recommended. In severe impairment (Child-Pugh C), quinine should not be administered. (1)
Monitoring
Before starting
- Confirm the diagnosis of uncomplicated P. falciparum malaria.
- Review contraindications: check for prolonged QT interval, G6PD deficiency, myasthenia gravis, optic neuritis, and hypersensitivity history.
- Assess concurrent medications for interactions (especially QT-prolonging drugs, digoxin, warfarin, and CYP3A4 modulators).
- Establish baseline kidney and liver function.
During treatment
- Monitor for signs of cinchonism (tinnitus, headache, visual changes) and report if severe.
- Watch for hematologic toxicity: bruising, bleeding, signs of HUS/TTP.
- Assess cardiac function if symptoms suggest arrhythmia; consider ECG monitoring in high-risk patients.
- Monitor blood glucose, especially in those at risk for hypoglycemia.
- Ensure completion of the full 7-day course to prevent recrudescence.
Storage
Store at 20°C to 25°C (68°F to 77°F) in a tight container. Keep out of reach of children.
Professional information
Clinician-facing context only. Use the current local indication, dosing recommendations, and monitoring guidelines.
United States
Indication: Uncomplicated Plasmodium falciparum malaria
Dose summary: Adults 16 years and older: 648 mg (two 324 mg capsules) every 8 hours for 7 days.
Renal context: Severe renal impairment: loading dose 648 mg, then 324 mg every 12 hours for 7 days. (1)
Hepatic guidance
Mild to moderate impairment: no dose adjustment but close monitoring. Severe impairment (Child-Pugh C): quinine should not be administered.
Overdose note
Overdose may result in severe cinchonism, hypoglycemia, or cardiac arrhythmias. Management is supportive and may include poison center consultation. (1)
Frequently asked questions
Can I use quinine for leg cramps?
No. Quinine is not approved for leg cramps and carries a boxed warning because such use has caused life-threatening blood reactions. It should only be used for uncomplicated falciparum malaria. (1)
Why do I need to take it for exactly 7 days?
The approved regimen is 648 mg every 8 hours for 7 days. Completing the full course is important to cure the malaria and prevent it from returning. (1)
What is cinchonism?
Cinchonism is a cluster of quinine side effects that can include ringing in the ears, headache, nausea, and blurred vision. It can occur even at normal doses. Tell your healthcare provider if you experience these symptoms. (1)
What symptoms require urgent medical attention?
Seek emergency help if you have unusual bruising or bleeding, palpitations or fainting (heart rhythm problems), severe rash or blistering, or signs of low blood sugar like sweating and shakiness. (1)
What is the mechanism of action of quinine sulfate?
Quinine sulfate is an antimalarial agent active against Plasmodium falciparum. (1)
What is the generic name of Quinine sulfate?
The generic name is quinine sulfate. It is sold under brand names including QUALAQUIN. (1)
What class of drug is quinine sulfate?
Quinine sulfate is classed as: Antimalarial. (1)
References
- QUALAQUIN (quinine sulfate) capsules — prescribing informationU.S. National Library of Medicine / DailyMed · United States · accessed 2026-08-08 · source 1
- QUININE SULFATE CAPSULE [LUPIN PHARMACEUTICALS, INC.] — US prescribing information (DailyMed SPL)U.S. National Library of Medicine (DailyMed) · US · accessed 2026-08-14 · source 2
- quinine — RxNorm normalized drug concept (RXCUI 388472)U.S. National Library of Medicine (RxNorm) · US · accessed 2026-08-14 · source 3
Brand names by country
Single-ingredient quinine sulfate names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.
Priority countries
United States
- Chininum sulphuricum10 [hp_M], 12 [hp_C]2[hp_C], 6 [hp_C], 6 [hp_C]/6[hp_C], 200 [kp_C]/200[kp_C], 30 [hp_C], 100 [hp_C], 9 [hp_C]/9[hp_C] · hahnemann laboratories, inc.
- Chininum salicylicum30 [hp_C]/30[hp_C], 200 [kp_C]/200[kp_C] · boiron
Canada
- QUININE - ODAN