Certain strains of the malarial parasite Plasmodium falciparum have now developed a resistance to chloroquine, and quinine is again the preferred drug in some regions. Quinine also has been used medicinally to allay fever and pain, to induce uterine contractions during labor, and as a sclerosing, or hardening, agent in the treatment of varicose veins. It is added to soft drinks called tonics, which are often mixed with alcoholic beverages. Excessive dosage or continuous use of quinine may cause cinchonism, characterized by ringing in the ears, headache, dizziness, changes in blood pressure, and even death.
See F. Rocco, The Miraculous Fever-Tree (2003).
Alkaloid found in the bark of cinchona trees and shrubs. The chemical structure of this heterocyclic compound is large and complex, with several rings. For the 300 years preceding the 1940s, when newer antimalarials were developed, quinine was the only drug known to Western medicine for the prevention and treatment of malaria. The first chemical compound ever used successfully against an infectious disease, it has benefited more people than any other such drug in history and is still used to treat malaria, often in combination with other drugs. Quinine is also a flavouring agent in some carbonated beverages, including tonic water.
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