quinidine vs. quinine

quinidine

noun

Pharmacology.
  1. a colorless, crystalline alkaloid, C 2 0 H 2 4 N 2 O 2 , isomeric with quinine, obtained from the bark of certain species of cinchona trees or shrubs, used chiefly to regulate heart rhythm and to treat malaria.

quinine

noun

Chemistry, Pharmacology.
  1. a white, bitter, slightly water-soluble alkaloid, C 2 0 H 2 4 N 2 O 2 , having needlelike crystals, obtained from cinchona bark: used in medicine chiefly in the treatment of resistant forms of malaria.
  2. a salt of this alkaloid, especially the sulfate.