Potassium is a mineral that your body relies on for a number of healthy functions, most importantly for regulating your heart rate and blood flow. Low levels of potassium can lead to leg cramps, which are sometimes treated with quinine supplements, but this can be dangerous. You should consult your doctor before using any supplement, to avoid unwanted side effects as well as adverse interactions with other medications you may be taking.
Potassium levels depend on having the right amount of magnesium and sodium in your body. A diet high in salt can decrease your potassium levels and could lead to a need for potassium supplements. While a healthy diet typically provides sufficient potassium, you may need supplements if you are experiencing vomiting, excessive sweating or have a malabsorption disorder. If you overdose and end with too much potassium in your body, you can develop hyperkalemia. Muscle cramps are a common symptom of low levels of potassium.
While being treated for low potassium levels, you must tell your doctor about other supplements and medication you're taking, because the mineral interacts negatively with a wide range of other treatments such as quinine, heparin, ACE inhibitors, beta blockers, insulin and laxatives. At the same time, quinine should never be taken when you have low potassium levels or are being treated for many kinds of heart disease. Quinine is only approved for treating malaria, a serious disease transmitted by mosquito bites and primarily occurring in the tropics. It is often used off-label to treat leg cramps, but according to Medline Plus, you should never use it for this purpose and always take it only under a doctor's care. Quinine interacts with a wide array of medications that include cholesterol-lowering drugs, antidepressants and cough medicine.
Side effects of too much potassium can include nausea, stomach aches and diarrhea. High doses of potassium can lead to more serious side effects as well, such as an abnormal heart rhythm, chest pain and severe abdominal cramps. You may experience ringing in your ears and nausea from taking quinine. More serious complications from quinine supplements can include low blood sugar levels, deafness, fainting, hives, vomiting and chest pain. Taking quinine can also lead to nosebleeds, blurry vision, blisters and unusual bleeding.
Quinine is available only through a prescription, and the Food and Drug Administration has issued warnings that marketing quinine for any condition other than malaria is prohibited. Tonic water and other supplements manufactured before the FDA ruling in 2007 contain trace amount of quinine. The only brand of pharmaceutical quinine approved for use in the United States is called Qualaquin. Potassium, however, is a common ingredient in multivitamins and as stand-alone supplements in capsule, liquid and tablet form.