Qualaquin (Quinine) - Oral


Using Qualaquin to treat or prevent nighttime leg cramps has potentially severe side effects on your kidneys or blood cells, even up to death. Kidney failure can arise from the abnormal breakdown of red blood cells or thrombotic thrombocytopenic purpura, a disease where blood clots form throughout the body. It can cause a condition known as thrombocytopenia, low platelets resulting in severe bleeding problems.

What Is Qualaquin?

Qualaquin (quinine sulfate) is an antiparasitic medicine that treats uncomplicated malaria in adults and children over 16 years. Malaria is caused by parasites that enter the body through the bite of a mosquito. 

According to the CDC, uncomplicated malaria is a mild form of the disease with symptoms lasting six to 10 hours.

Qualaquin is available via prescription as a clear, 324 milligram (mg) hard gelatin capsule. 

Scientists don’t know exactly how it works in the body, but it is thought to limit how the malaria parasite makes energy and grows. It is important to note that Qualaquin can seriously harm your kidneys or blood cells when used to treat or prevent leg cramps.

Drug Facts

Generic Name: Quinine

Brand Name: Qualaquin, Quinamm, Quiphile

Drug Availability: Prescription

Administration Route: Oral

Therapeutic Classification: Musculoskeletal agent

Available Generically: Yes

Controlled Substance: N/A

Active Ingredient: Quinine

Dosage Form: Capsule

What Is Qualaquin Used For?

The Food and Drug Administration (FDA) approved Qualaquin for treating malaria (uncomplicated) caused by the parasite Plasmodium falciparum in adults and children aged 16 and older.

It is not approved to: 

  • Prevent malaria,
  • Treat severe or complicated malaria 
  • Prevent or treat nighttime leg cramps.
Qualaquin (Quinine Sulfate) Drug Information - Illustration by Zoe Hansen

Verywell / Zoe Hansen

How to Take Qualaquin

Use this medicine exactly as directed by your healthcare provider. Follow all the directions on your medicine label. Don’t take more than you are prescribed.

Take each dose with food to reduce upset stomach. It is important to finish all of the capsules as prescribed, even if you start feeling better. Do not stop taking this medication without talking to your provider.  

Ask a healthcare provider if you do not understand how to take your medications.


Store Qualaquin capsules in a tightly closed container at room temperature of 68 degrees to 77 degrees Fahrenheit. Keep away from moisture (do not store in the bathroom), heat, and out of the reach of children and pets. Do not refrigerate or freeze. When traveling, transport Quinine in your carry-on or your checked baggage with its original label.

Off-Label Uses 

Quinine is sometimes prescribed to treat/prevent nighttime leg cramps or treat babesiosis. These are not FDA-approved uses and there is no evidence that quinine effectively treats or prevents these conditions. Misusing this medication without the advice of a provider can result in severe or life-threatening side effects.

How Long Does Qualaquin Take to Work?

Qualaquin enters the bloodstream in a few hours and starts working. It is removed from the body in a couple of days.

What Are the Side Effects of Qualaquin? 

This is not a complete list of side effects, and others may occur. A medical professional can advise you on side effects. If you experience other effects, contact your pharmacist or a medical professional. You may report side effects to the FDA at fda.gov/medwatch or 1-800-FDA-1088.

Common Side Effects

Common side effects of Qualaquin can include:

  • Headache
  • Blurred vision or changes in color vision
  • Dizziness or spinning sensation
  • Ringing in your ears or loss of hearing
  • Sweating or flushing (warmth, redness, or tingling)
  • Stomach pain
  • Nausea or vomiting
  • Diarrhea
  • Fever
  • Chills
  • Weakness
  • Rashes, itchy skin, hives, or welts
  • Photosensitivity (sun sensitivity)

Severe Side Effects

Call your healthcare provider right away if you have serious side effects. Call 911 immediately if your symptoms feel life-threatening or if you think you or someone else is having a medical emergency. Serious side effects can include the following:

Report Side Effects

Qualaquin may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Qualaquin Should I Take?

Drug Content Provided and Reviewed by IBM Micromedex®

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage form (capsules):
    • For treatment of malaria:
      • Adults and children 16 years of age and older—648 milligrams (mg) (2 capsules) every 8 hours for 7 days.
      • Children younger than 16 years of age—Use and dose must be determined by your doctor.


Tell your healthcare provider if you are pregnant or plan to become pregnant while using this medication. It is not known whether Qualaquin will harm the fetus during pregnancy. Qualaquin may cause low blood sugar, especially during pregnancy. If symptoms of low blood sugar occur (sudden sweating, shaking, fast heartbeat, hunger, blurred vision, dizziness), increase your blood sugar by eating a quick source of sugar such as honey, candy, or drink fruit juice or non-diet soda.

Quinine may harm a nursing baby by passing into breast milk. It may be dangerous in babies with a particular genetic disorder called G6PD deficiency. Tell your provider if you are breastfeeding.

Do not give this medication to a child under the age of 16.

Missed Dose 

If you miss a dose of this medication, take it as soon as you remember. You can skip the missed dose if you are more than four hours late. Resume medication at your next scheduled time. Do not take extra to make up for the missed dose. Call your provider if you are unsure of what to do.

Overdose: What Happens If I Take Too Much Qualaquin?

Qualaquin overdose can happen if you take too much of it. An overdose can cause serious complications, such as:

  • Cinchonism
  • Visual impairment
  • Hypoglycemia
  • Heart arrhythmias
  • Death

Central nervous system toxicity has also been reported. Symptoms can include:

  • Drowsiness
  • Disturbances of consciousness
  • Ataxia
  • Convulsions
  • Respiratory depression
  • Coma

Pulmonary edema and acute respiratory distress syndrome can also occur.

What Happens If I Overdose on Qualaquin?

If you think you or someone else may have overdosed on Qualaquin, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Qualaquin, call 911 immediately.


Drug Content Provided and Reviewed by IBM Micromedex®

It is very important that your doctor check your or your child's progress after you finish using the medicine. This is to make sure the malaria is cleared up completely. Blood and urine tests may be needed to check for unwanted effects.

Contact your doctor right away if you have any changes to your heart rhythm. You might feel dizzy or faint, or you might have a fast, pounding, or uneven heartbeat. Make sure your doctor knows if you or anyone in your family has ever had a heart rhythm problem such as QT prolongation.

Check with your doctor right away if you have any unusual bleeding or bruising, black, tarry stools, blood in the urine or stools, headache, dizziness, or weakness, pain, swelling, or discomfort in a joint, pinpoint red spots on your skin, unusual nosebleeds, or unusual vaginal bleeding that is heavier than normal. These may be signs of bleeding problems.

Be extra careful to avoid injuries. Stay away from rough sports or other situations where you could be bruised, cut, or injured. Gently brush and floss your teeth. Be careful when using sharp objects, including razors and fingernail clippers.

This medicine may cause hemolytic anemia (blood disorder). Check with your doctor right away if you have back, leg, or stomach pains, bleeding gums, chills, dark urine, difficulty breathing, fever, swelling, headache, loss of appetite, nausea, vomiting, nosebleeds, pale skin, sore throat, or yellowing of the eyes or skin.

This medicine may cause serious allergic reactions, including anaphylaxis, which can be life-threatening and requires immediate medical attention. Call your doctor right away if you have a rash, itching, hoarseness, lightheadedness, dizziness, or fainting, trouble breathing, trouble swallowing, or any swelling of your hands, face, or mouth after you use this medicine.

Serious skin reactions can occur with this medicine. Check with your doctor right away if you have blistering, peeling, or loosening of the skin, red skin lesions, severe acne or a skin rash, sores or ulcers on the skin, or fever or chills with this medicine.

Quinine may cause hypoglycemia (low blood sugar). If your blood sugar gets too low, you may feel weak, drowsy, confused, anxious, or very hungry. You may also sweat, shake, or have blurred vision, a fast heartbeat, or a headache that will not go away. Tell your doctor right away if you have any of these symptoms.

Before you have any medical tests, tell the medical doctor in charge that you are using this medicine. The results of some tests may be affected by this medicine.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

What Are the Reasons I Shouldn’t Take Qualaquin? 

Avoid taking Qualaquin if you:

What Other Medications Interact With Qualaquin

Watch out for these medications when taking Qualaquin, as they can affect how it works in the body.

Drugs that can interact with Qualaquin include:

  • Other antimalaria medications
  • CYP3A4 inducers or inhibitors
  • Heart medications
  • Antacids
  • Seizure medications
  • Stomach acid reducers
  • Antifungal medications
  • Antibiotics
  • Tuberculosis medications
  • Theophylline or aminophylline
  • Urinary alkalizers
  • HIV/AIDS or hepatitis C medications

Other Antimalaria Medications

Avoid taking other antimalarials while on Qualaquin. The combination can cause serious life-threatening heart issues and increase the risk of seizures. Antimalarial medications include:

  • Aralen Phosphate (chloroquine)
  • Halofantrine
  • Lariam (mefloquine)

CYP3A4 Inducers or Inhibitors

Quinine may affect the metabolism of certain drugs that leave the body the same way it does. 

It should also be avoided with some medicines used to treat a psychiatric disorder, such as:

  • Chlorpromazine
  • Clozaril, FazaClo, Versacloz (clozapine)
  • Haldol (haloperidol)
  • Mesoridazine
  • Orap (pimozide)
  • Thioridazine
  • Geodon (ziprasidone)

It should also be avoided with medications known to cause QT prolongation, including:

  • Astemizole
  • Prepulsid, Propulsid (cisapride)
  • Terfenadine
  • Pimozide
  • Halofantrine

The combination may increase the risk of QT prolongation and irregular heartbeat. 

Heart Medications

Quinine should not be combined with certain heart medications such as:

  • Cordarone, Pacerone (amiodarone)
  • Digitek, Digox, Lanoxicaps, Lanoxin (digoxin)
  • Tikosyn (dofetilide)
  • Norpace, Norpace CR (disopyramide)
  • Multaq (dronedarone)
  • Tambocor (flecainide)
  • Corvert (Ibutilide)
  • Lopressor, Toprol XL (metoprolol)
  • Pronestyl (procainamide)
  • Rythmol, Ryhtmol SR (propafenone)
  • Betapace, Betapace AF, Sorine, Sotylize (Sotalol)
  • Calan, Calan SR, Covera-HS, Verelan, Verelan PM (verapamil)

The combination may increase the risk of QT prolongation, irregular heartbeat, and toxicity.


Some antacids (containing aluminum and/or magnesium) may make it harder for your body to absorb Qualaquin. Avoid using them while taking quinine.

Seizure Medications

Seizure medications, or anticonvulsants, may decrease quinine levels in the body if used simultaneously. 

Examples include:

Stomach Acid Reducers

When taken with cimetidine or ranitidine, the levels of Qualaquin in the body may increase. This may raise the risk of experiencing side effects associated with Qualaquin. 

Antifungal Medications

The combination may increase the risk of QT prolongation and irregular heartbeat. Examples include: 

  • Onmel, Sporanox (itraconazole)
  • Nizoral (ketoconazole)
  • Noxafil, Noxafil PowderMix (posaconazole)
  • Vfend (voriconazole)
  • Diflucan (fluconazole)


The combination may increase Qualaquin levels in the body and increase the risk of experiencing side effects. Examples are: 

  • Zithromax (azithromycin)
  • Biaxin (clarithromycin)
  • Ery-Tab (erythromycin)
  • Levaquin (levofloxacin)
  • Avelox (moxifloxacin)
  • Nebupent, Pentam (pentamidine)
  • Ketek (telithromycin)
  • Actisite (tetracycline)
  • Troleandomycin

Tuberculosis Medications 

Medications for tuberculosis can decrease the amount of Qualaquin available in the body and make it less effective. Examples include: 

  • Mycobutin (rifabutin)
  • Rifadin, Rimactane (rifampin)
  • Priftin (rifapentine)

Theophylline or Aminophylline

The combination may increase Qualaquin levels in the body, and therefore increase the risk of experiencing side effects. 

Urinary Alkalizers

Urinary alaklizers, such as acetazolamide and sodium bicarbonate, can increase Qualaquin levels in the body and increase the risk of side effects. 

HIV/AIDS or Hepatitis C Medications

The combination may increase Qualaquin levels in the body and increase the risk of experiencing side effects. Examples of these medications include:

  • Victrelis (boceprevir)
  • Incivek (telaprevir)
  • Reyataz (atazanavir)
  • Rescriptor (delavirdine)
  • Sustiva (efavirenz)
  • Lexiva (fosamprenavir)
  • Crixivan (indinavir)
  • Viracept (nelfinavir)
  • Viramune (nevirapine)
  • Norvir (ritonavir)
  • Invirase (saquinavir)

This is not a comprehensive list of medications that may affect how Qualaquin works. Tell your healthcare provider or pharmacist about all your current medicines and supplements. Some medicines can increase the risk of severe side effects from quinine. 

What Medications Are Similar? 

Medications similar to Qualaquin include:

  • Coartem (artemether and lumefantrine)
  • Mefloquine hydrochloride
  • Malarone (atovaquone and proguanil)

Coartem (Artemether and Lumefantrine)

Coartem combines two antimalarial drugs (artemether and lumefantrine) to treat non-severe malaria in adults and children at least 2 months old or who weigh at least 11 pounds. It works by interfering with the growth of parasites that cause malaria in the body. 

Unlike Qualaquin, Coartem is better suited for children. It can also make hormonal birth control less effective, so this may not be the best option for you if you use hormonal birth control.  

Plaquenil (Hydroxychloroquine)

Hydroxychloroquine is a medicine used to treat or prevent malaria. The exact way it does this is unknown, but it is believed to interrupt the parasite that causes malaria in the red blood cell. It is not effective in treating all malaria strains or treating malaria in areas where the infection has been resistant to chloroquine.

Hydroxychloroquine is also better suited for pediatric populations than Qualaquin. It prevents and treats malaria in adults and children who weigh at least 68 pounds. Hydroxychloroquine also treats symptoms of rheumatoid arthritis or lupus. Unlike quinine, hydroxychloroquine must not be cut, crushed, or chewed. Therefore, those that may have trouble swallowing can’t use it. Taking hydroxychloroquine for a long time or at high doses may permanently damage your eye. Do not take more than prescribed. 

Malarone (Atovaquone and Proguanil)

Malarone is a combination of two antimalarial drugs: atovaquone and proguanil. It works by interfering with the growth of parasites that cause malaria in the body. Unlike quinine which treats an active infection, Malarone is also used to prevent malaria.

Those with severe kidney disease can’t use Malarone. If in this category, Qualaquin might be a better option for you. Malarone is also better suited for pediatric populations than Qualaquin. It treats non-severe malaria in adults and children who weigh at least 11 pounds. It prevents malaria in adults and children who weigh at least 24 pounds.

Frequently Asked Questions

  • How does Qualaquin work?

    The exact way quinine treats malaria is not entirely understood. It may interfere with the parasite’s ability to break down and digest heme. Heme is toxic to Plasmodium falciparum, the malaria parasite, and kills it off. It is also thought to inhibit other cellular processes that can cause the parasite to starve.

  • What drugs should not be taken with Qualaquin?

    Avoid taking other antimalaria medications without consulting with your healthcare provider. Medications like chloroquine, halofantrine, and mefloquine. Also, avoid using antacids with quinine without your healthcare provider's advice. Some antacids can make it more difficult for your body to absorb quinine. Other medications may affect how Qualaquin works. Tell your healthcare provider before you start taking any new medicines.

  • When should I stop taking Qualaquin?

    Qualaquin can harm your heart, kidneys, or blood cells. Stop taking it and call your provider immediately if you have: 

    • A headache with chest pain and dizziness
    • Fast or pounding heartbeat
    • Easy bruising or bleeding (nosebleeds, bleeding gums, blood in your urine or stool)
    • Purple or red spots under your skin
    • Fever, chills, mouth sores
    • Severe lower back pain

    Those that are allergic to quinine may experience an anaphylaxis reaction. This reaction develops suddenly and can be life-threatening. Stop taking this medicine and call 911 if you experience hives, swelling of the tongue, face, or throat, difficulty breathing, and a rapid or slowed heartbeat after taking quinine.

How Can I Stay Healthy While Taking Qualaquin?

Malaria is a rare infection in the United States (approximately 200 cases per year) mainly resulting from travel abroad. Even though it is a potentially fatal disease, prevention is the best approach. Preventive medications should be combined with protective measures like using insect repellent, wearing long sleeves and long pants, or sleeping with an insecticide-treated bednet.

Quinine will not treat severe malaria or prevent it. It is also not approved to treat or prevent nighttime leg cramps. Patients using Qualaquin for this condition are at risk for serious side effects. Do not use this medicine to treat any condition your healthcare provider has not checked.

If you have trouble taking this medication, consider setting alarms on your phone or calendar. 

Contact your healthcare provider if you have any questions about the medication.

Medical Disclaimer

Verywell Health's drug information is meant for education purposes only and not intended as a replacement for medical advice, diagnosis, or treatment from a healthcare professional. Consult your doctor before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Centers for Disease Control and Prevention. Parasites - malaria.

  2. Food and Drug Administration. Qualaquin label.

  3. Food and Drug Administration. Coartem label.

  4. Food and Drug Administration. Plaquenil label.

  5. Food and Drug Administration. Malarone label.