Side Effects of Quinine

Quinine is used to treat malaria, a disease caused by parasites. Parasites that cause malaria typically enter the body through the bite of a mosquito. Malaria is common in areas such as Africa, South America, and Southern Asia.
Quinine will not treat severe forms of malaria, and it should not be taken to prevent malaria. Quinine also should not be taken to treat or prevent night-time leg cramps. Using this medication improperly or without the advice of a doctor can result in serious side effects or death. Quinine is approved for use only in treating malaria. Some people have used quinine to treat leg cramps, but this is not an FDA-approved use.

The U.S. Food and Drug Administration has banned the sale of all non-approved brands of quinine. As of December 2006, Qualaquin is the only brand of quinine that is approved by the FDA.

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Stop using quinine and call your doctor at once if you have any of these serious side effects:

  • fever, chills, confusion, weakness, sweating;
  • severe vomiting, stomach pain, diarrhea;
  • problems with vision or hearing;
  • chest pain, trouble breathing, severe dizziness, fainting, fast or pounding heartbeats;
  • severe flushing (warmth, redness, or tingly feeling);
  • urinating less than usual or not at all;
  • weak or shallow breathing, feeling like you might pass out;
  • easy bruising, unusual bleeding (nose, mouth, vagina, or rectum), purple or red pinpoint spots under your skin;
  • blood in your urine or stools;
  • fever, sore throat, and headache with a severe blistering, peeling, and red skin rash; or
  • loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes).

Less serious side effects may include:

  • headache, blurred vision, changes in color vision;
  • mild dizziness, spinning sensation, ringing in your ears;
  • upset stomach; or
  • muscle weakness.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.
Do not use this medication if you have ever had an allergic reaction to quinine or similar medicines such as mefloquine (Lariam) or quinidine (Cardioquin, Quinidex, Quinaglute, Quin-G), or if you have:

  • a heart rhythm disorder called Long QT syndrome;
  • an enzyme deficiency called glucose-6-phosphate dehydrogenase (G-6-PD) deficiency;
  • a blood clotting disorder;
  • myasthenia gravis; or
  • optic neuritis (inflammation of the optic nerve).

To make sure you can safely take quinine, tell your doctor if you have any of these other conditions:

  • heart disease or a heart rhythm disorder;
  • low potassium levels in your blood (hypokalemia); or
  • kidney or liver disease.