• Antimyotonic
• antiprotozoal

Quinine (KWYE-nine) is used to treat malaria. This medicine usually is given with one or more other medicines for malaria.

Quinine may also be used for other problems as determined by your doctor. Do not confuse quinine with quinidine, a different medicine that is used for heart problems.

Quinine is available only with your doctor's prescription in the following dosage forms:

Oral
• Capsules (U.S. and Canada)
• Tablets (U.S.)

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For quinine, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to quinine, quinidine (e.g., Quinidex), or to dietary items that contain quinine, such as tonic water or bitter lemon. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy—Quinine has been used for the treatment of malaria in pregnant women. Treatment is important because if a pregnant woman gets malaria, there is an increased chance of premature births, stillbirths, and abortion. However, quinine has been shown to cause birth defects in rabbits and guinea pigs and has also been shown to cause rare birth defects, stillbirths, and other problems in humans. In addition, quinine has been shown to cause miscarriage when taken in large amounts.

Breast-feeding—Quinine passes into the breast milk in small amounts. However, this medicine has not been reported to cause problems in nursing babies.

Children—This medicine has been used to treat malaria in children and, in effective doses, has not been shown to cause different side effects or problems in children than it does in adults.

Older adults—Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults or if they cause different side effects or problems in older people. There is no specific information comparing use of quinine in the elderly with use in other age groups.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking quinine, it is especially important that your health care professional know if you are taking the following:

• Mefloquine (e.g., Lariam)—Use of mefloquine with quinine may increase the chance of side effects

• Blackwater fever, history of, or
• Glucose-6-phosphate dehydrogenase (G6PD) deficiency or
• Purpura, or history of (purplish or brownish-red discoloration of skin)—Patients with a history of blackwater fever, G6PD deficiency, or purpura may have an increased risk of side effects affecting the blood

• Heart disease—Quinine can cause side effects affecting the heart, usually at higher doses

• Hypoglycemia—Quinine may cause low blood sugar

• Myasthenia gravis—Quinine may increase muscle weakness in patients with myasthenia gravis

Take this medicine only as directed. Do not take more of it, do not take it more often, and do not take it for a longer time than recommended on the label , unless otherwise directed by your doctor. To do so may increase the chance of side effects.

Take this medicine with or after meals to lessen possible stomach upset, unless otherwise directed by your doctor. If you are to take this medicine at bedtime, take it with a snack or with a glass of water, milk, or other beverage.

For patients taking quinine for malaria:

• To help clear up your infection completely, keep taking this medicine for the full time of treatment, even if you begin to feel better after a few days. If you stop taking this medicine too soon, your symptoms may return. Do not miss any doses .

Dosing—

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

The number of capsules or tablets 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 taking quinine.

• For treatment of malaria:
  • Adults and teenagers: 600 to 650 mg every eight hours for at least three days. This medicine must be taken with other medicine to treat malaria.
  • Children: Dose must be determined by the doctor.

Missed dose—

If you do miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage—

To store this medicine:

• Keep out of the reach of children.
• Store away from heat and direct light.
• Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
• Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.

Quinine may cause blurred vision or a change in color vision. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are not able to see well . If these reactions are especially bothersome, check with your doctor.

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

• More common
  • Abdominal or stomach cramps or pain;  diarrhea;  nausea;  vomiting  
  
  

• Less common
  • Anxiety;  behavior change, similar to drunkenness;  black, tarry stools;  blood in urine or stools;  blurred vision;  cold sweats;  confusion;  convulsions (seizures) or coma;  cool pale skin;  cough or hoarseness;  difficulty in concentrating;  drowsiness;  excessive hunger;  fast heartbeat;  fever or chills;  headache;  lower back or side pain;  nervousness ;  nightmares;  painful or difficult urination;  pinpoint red spots on skin;  restless sleep;  shakiness;  slurred speech;  sore throat;  unusual bleeding or bruising;  unusual tiredness or weakness 
  
  

• Rare
  • Difficulty in breathing and/or swallowing;  disturbed color perception;  double vision;  hives;  increased sweating;  muscle aches;  night blindness;  reddening of the skin, especially around ears;  ringing or buzzing in ears;  swelling of eyes, face, or inside of nose 
  
  

• Signs and symptoms of overdose
  • Blindness;  chest pain;  dizziness;  double vision;  fainting;  lightheadedness;  rapid or irregular heartbeat;  sleepiness  
  
  

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects occur or progress after you stop taking this medicine:

• Blurred vision or change in vision  

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.

Once a medicine has been approved for marketing for a certain use, experience may show that it is also useful for other medical problems. Although these uses are not included in product labeling, quinine is used in certain patients with the following medical conditions:

• Babesiosis (infection caused by parasites)
• Nighttime leg cramps

Other than the above information, there is no additional information relating to proper use, precautions, or side effects for these uses.