Cinchonism

Cinchonism or quinism is poisoning from an overdose of cinchona alkaloids. Cinchona bark is the source of quinine and quindine. Quinine is used to treat malaria. In small amounts it is used in tonic water to give a bitter flavor. Cinchoism can be caused by medical doses of quinine or quindine.

Signs and symptoms

Symptoms of mild cinchonism can include:

• flushed and sweaty skin
• ringing of the ears (tinnitus)
• blurred vision
• hearing loss
• confusion
• reversible high-frequency hearing loss
• headache
• abdominal pain
• rashes
• drug-induced lichenoid reaction (lichenoid photosensitivity)
• vertigo
• dizziness
• dysphoria
• nausea
• vomiting
• diarrhea.

Large doses of quinine can cause:

• skin rashes
• deafness
• sleepiness
• blindness
• anaphylactic shock
• disturbances in abnormal heart rhythm
• death from cardiotoxicity.

People treated with quinine may also suffer from low blood sugar and hypotension (low blood pressure).

Most symptoms of cinchonism (except in severe cases) are reversible and disappear once quinine is withdrawn.