Signs and
symptoms of mild cinchonism (which may occur from standard therapeutic doses of quinine) include
flushed and sweaty skin, ringing of the ears (
tinnitus), blurred vision, impaired hearing, confusion, reversible high-frequency hearing loss, headache, abdominal pain, rashes,
drug-induced lichenoid reaction (
lichenoid photosensitivity),
vertigo,
dizziness,
nausea,
vomiting and
diarrhea. Large doses of quinine may lead to severe (but reversible) symptoms of cinchonism: skin rashes, deafness,
somnolence, diminished visual acuity or blindness,
anaphylactic shock, and disturbances in
heart rhythm or conduction, and death from cardiotoxicity (damage to the heart). Quinine may also trigger a rare form of hypersensitivity reaction in malaria patients, termed
blackwater fever, that results in massive
hemolysis,
hemoglobinemia,
hemoglobinuria, and
kidney failure. Most symptoms of cinchonism (except in severe cases) are reversible and disappear once quinine is withdrawn. Attempted suicide by intake of a large dose of quinine has caused irreversible tunnel vision and very severe visual impairment. Patients treated with quinine may also suffer from
low blood sugar, especially if it is administered
intravenously, and
hypotension (low
blood pressure). Quinine, like
chloroquine, inactivates enzymes in the
lysosomes of cells and has an anti-inflammatory effect, hence its use in the treatment of
rheumatoid arthritis. However, inactivation of these enzymes can also cause abnormal accumulation of glycogen and phospholipids in lysosomes, causing toxic
myopathy. It is possible this action is the root cause of cinchonism. == References ==