Quinine is a Levo rotatory alkaloid that is obtained from cinchona bark.
Its d-isomer quinidine is used as an antiarrhythmic and against the malaria parasite.
It is used against all species of plasmodia, but it is less effective and more toxic than chloroquine.
Mechanism of action.
- Inhibits heme polymerase activity, resulting in the accumulation of toxic free heme to the parasites.
Clinical uses.
- Quinine is used orally for uncomplicated chloroquine-resistant malaria and intravenously for complicated cerebral malaria.
- Used orally for uncomplicated resistant falciparum malaria.Used for nocturnal muscle cramps.
- Quinine is also effective in the management of myotonia congenita.
Adverse effects
- Cinchonism syndrome is characterized by;
√ringing in ears
√nausea and vomiting; due to gastric irritation and CTZ stimulation.
√ headache and mental confusion
√vertigo.
√Difficulty in hearing and visual defects; due to direct neurotoxicity and constriction of retinal and auditory vessels.
- Diarrhea, flushing, and cardiac function disturbance.
- Asthma precipitation.
Contraindications.
- Optic neuritis
- Tinnitus
- Hemolysis
- Myasthenia gravis
Dosage.
- REZOQUIN, QUININE, QUINARSOL 300, 600 mg tablets.
