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Overview: Quinine is used to treat malaria. Common side effects include nausea, vomiting, diarrhea, stomach pain, and headache. Serious side effects are less common but can include allergic reactions or heart problems. Before taking quinine, make sure to tell your health care provider about any health conditions or medicines you are taking.

Uses

What is quinine used for?

Quinine is commonly used to treat malaria.

Quinine may not be the right medicine for some of the infections listed above, depending on which germs are causing the infection. Germs in some locations may be resistant to quinine, which will make it not work as well.

Quinine may also be used for other conditions as determined by your health care provider.

How does quinine work (mechanism of action)?

Quinine kills certain parasites by blocking their ability to create energy and proteins that they need to survive.

How is quinine supplied (dosage forms)?

Brands and other names

  • Qualaquin

Dosage forms and strengths

  • 324 mg oral capsules

How should I store quinine?

Quinine should be stored at room temperature, between 68 F and 77 F (20 C and 25 C). It can be exposed to temperatures between 59 F and 86 F (15 C and 30 C) for shorter periods of time, such as when transporting it. Store in a cool, dry place. Keep the container tightly closed.

Side Effects

What are the most common side effects of quinine?

The most common side effects of quinine are listed below. Tell your health care provider if you have any of these side effects that bother you.

  • Headache
  • Sweating
  • Flushing
  • Nausea and vomiting
  • Ringing in the ears or hearing loss
  • Diarrhea
  • Dizziness
  • Blurred vision, changes in how you see color, or vision loss
  • Stomach pain
  • Heart rhythm changes (see below)

There may be other side effects of quinine that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088 (800-332-1088). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of quinine?

While less common, the most serious side effects of quinine are described below, along with what to do if they happen.

Severe Allergic Reactions. Quinine may cause allergic reactions, which can be serious. Stop taking quinine and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Severe Skin Reactions. Quinine can cause severe skin reactions, called Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), that can lead to death if not treated. If you get a rash, stop taking/using quinine and call your health care provider right away. Get emergency help if you have any of the following symptoms of SJS or TEN.

  • Painful red or purple skin that looks burned and peels off
  • Flat red rash or blisters on your skin, mouth, nose, and genitals
  • Red, painful, watery eyes
  • Flu-like symptoms including fever, chills, and muscle aches

Blood Disorders. Quinine may cause your red blood cells to be destroyed, which is called hemolytic anemia. Your health care provider may run tests and stop quinine if you have hemolytic anemia.

Heart Rhythm Changes. Quinine may cause a rare, dangerous heart rhythm problem called QT prolongation and torsade de pointes. Some people have a higher risk for this, including people who are older, have other people in their family who have had these conditions, have low potassium or magnesium levels, or who take medicines that can prolong the QT interval. Tell your health care provider right away if you faint or have changes in your heart rate or rhythm, such as a fast or skipping heartbeat.

Low Blood Sugar (Hypoglycemia). Quinine can cause low blood sugar, which can be serious and may lead to death. Those who are pregnant may be at higher risk. You may need to check your blood sugar more often if you have changes to your diet, exercise regimen, or medicines for diabetes. Do not take quinine and call your health care provider right away if you have any of the following symptoms of hypoglycemia.

  • Headache
  • Crankiness or anxiety
  • Hunger
  • Dizziness or confusion
  • Blurry vision
  • Slurred speech
  • Sweating
  • Feeling jittery or shakiness
  • Fast heartbeat
  • Seizures

Thrombotic Thrombocytopenic Purpura (TTP). Quinine can lead to a serious problem with blood clotting, called TTP. TTP is when blood clots form in some parts of your bloodstream, which causes a loss of platelets in the rest of the blood (thrombocytopenia). This can sometimes lead to kidney problems, including hemolytic uremic syndrome (HUS). TTP needs to be treated right away in the hospital or it can lead to death. Get emergency help if you have any of the following symptoms without another explanation.

  • Fever
  • Shortness of breath
  • Pale or yellowish skin
  • Your skin or the whites of your eyes turning yellowish in color (also called jaundice)
  • Changes in your vision
  • Unusual weakness or tiredness
  • Headache, confusion, or slurred speech
  • Fast heartbeat
  • Purplish spots (purpura) on the skin or in the mouth due to bleeding under the skin
  • Low amount of pee or pee that is pink or has blood in it

Warnings & Precautions

Who should not take quinine?

Allergies to Ingredients. People who are allergic to any of the following should not take quinine.

  • Mefloquine
  • Qualaquin
  • Quinidine
  • Quinine
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific quinine products they stock.

Heart Rhythm Problems. Quinine should not be taken if you have a certain type of electrocardiogram (ECG) abnormality known as QT prolongation.

Quinine Side Effects. If you have taken quinine before and it caused severe side effects, such as low platelet levels, thrombotic thrombocytopenic purpura, idiopathic thrombocytopenic purpura, hemolytic uremic syndrome (HUS), or blackwater fever, you should not take quinine again. Tell your health care provider if you had any side effects with quinine in the past.

Muscle Weakness. Quinine should not be taken if you have a condition called myasthenia gravis.

Eye Problems. Quinine should not be taken if you have a condition called optic neuritis.

What should I know about quinine before using it?

Do not take quinine unless it has been prescribed to you by a health care provider. Take it as prescribed.

Do not share quinine with other people, even if they have the same condition as you. It may harm them.

Keep quinine out of the reach of children.

Take quinine with food to help keep it from upsetting your stomach.

What should I tell my health care provider before using quinine?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if quinine is right for you.

In particular, make sure that you discuss any of the following.

Planned Surgery. Quinine may affect other medicines that are used during surgeries.

Current and Past Health Conditions. Tell your health care provider if you have any of the following.

  • Heart problems, such as a too fast or too slow heart rate
  • Kidney problems
  • Liver problems
  • Low potassium levels
  • Glucose-6-phosphate dehydrogenase or G6PD deficiency

Other Medicines and Supplements. Quinine may interact with other medicines and supplements. Before taking quinine, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. It is not known if or how quinine could affect pregnancy or harm an unborn baby. Tell your health care provider if you are or plan to become pregnant. Your health care provider will advise you if you should take quinine while you are pregnant or trying to get pregnant.

Breastfeeding. Quinine passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed. Your health care provider will advise you if you should take quinine while breastfeeding.

Interactions

Does quinine interact with foods or drinks?

There are no known interactions between quinine and foods or drinks.

It is unknown if drinking alcohol will affect quinine, but heavy drinking can slow your immune response and make it harder for your body to fight infections.

Does quinine interact with other medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before taking quinine.

  • Medicines that can cause QT prolongation, which is a potentially dangerous heart rhythm problem, such as amiodarone, disopyramide, dofetilide, pimozide, procainamide, quinidine, or sotalol
  • An antacid containing aluminum or magnesium
  • A medicine for seizures, such as carbamazepine, phenytoin, or phenobarbital
  • An H2 blocker, such as cimetidine (Tagamet) or ranitidine (Zantac)
  • Ketoconazole, which is a medicine used for fungal infections
  • A macrolide antibiotic, such as erythromycin (Ery-Tab and others), which is a medicine used for bacterial infections
  • Dextromethorphan, which is a cough suppressant
  • Rifampin (Rifadin), which is a medicine commonly used to treat an infection called tuberculosis
  • Ritonavir (Norvir), which is a medicine commonly used to treat HIV
  • Tetracycline, which is a medicine used to treat infections or other conditions
  • Aminophylline or theophylline, which is a medicine for asthma or certain other breathing problems
  • Acetazolamide or sodium bicarbonate, which may be used to lower the acid in your urine
  • A statin, such as atorvastatin (Lipitor and others), which is a medicine to lower cholesterol
  • An antidepressant, such as desipramine or paroxetine
  • Digoxin (Lanoxin), which is a medicine used to treat irregular heartbeat and some types of heart failure
  • Mefloquine, which is a medicine used to treat malaria
  • A blood thinner, such as warfarin (Coumadin)
  • Flecainide, which is a medicine used for irregular heart rhythm
  • Metoprolol (Lopressor) or verapamil (Verelan, Verelan PM), which is a medicine used for high blood pressure or chest pain

Many other medicines may alter the blood levels of quinine, and vice versa. Tell your health care provider about all medicines that you take or have recently taken.

This may not be a complete list of medicines that can interact with quinine. Always check with your health care provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally take too much quinine?

If you or someone else has taken too much quinine, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of quinine?

Missing doses of quinine can cause it to not work as well over time. So it is important not to miss or skip doses.

If you miss a dose, take it as soon as you remember. If it has been more than 4 hours since the missed dose was due, skip the missed dose and only take the next dose. Do not take double or extra doses.