The salt obtained from the bark of cinchona calisaya. Sulphate of quinine is the form mostly employed.
Physiological action: Quinine in large doses has produced permanent deafness and in some cases temporary blindness. In doses of from 4 to 6 grains taken 3 or 4 times a day, it produces very often engorgement of the brain, headache, throbbing in the head, ringing in the ears, impairment of hearing, nervous excitement and even confusion of the mind. If dose is increased and continued there will follow restlessness, sleeplessness, general debility, feeble pulse, dilated pupils, coolness of extremities, partial or complete loss of voice, hearing and sight. Large doses, often repeated, cause disturbance of the gastro-intestinal tract, dizziness, headache and even delirium. Quinine in very small doses is a tonic, in medium doses a stimulant and in large doses a depressant. It acts on the cerebro-spinal nervous system and on the heart through the ganglionic nervous system.
Indications: In diseases with periodicity. When skin is soft and inclined to moisture. Tongue moist and not dirty. Full, soft and open pulse.
Use: In all conditions where there is marked periodicity and where the secretory functions are in working condition, the use of quinine is not followed by any unpleasant results. For this reason in periodical fevers it should be given during intermission if it is indicated in the case. In small doses it stimulates; while in large doses it depresses. It acts on the cerebro-spinal nervous system and the ganglionic nervous system of the heart. In congestive chills it should be given before the attack if possible, and stimulants given during the attack. Average dose is from 2 to 5 grains every 2 to 4 hours. In congestive chills 9 to 15 grains may be given before attack.