Chloroquine is a medication, which has been most widely used for the treatment and prevention of malaria. Currently, its use is more limited due to the development of P. falciparum resistance in many endemic foci of tropical malaria.
Mechanism of Action
This drug has a protozoacid effect, which is associated with blocking of the nucleic acids synthesis. Chloroquine also exhibits a slowly developing anti-inflammatory activity, therefore, it is used for some rheumatological diseases, as well as for photodermatitis.
Indications for Use
Usually Chloroquine is prescribed for treatment of the following diseases:
Malaria caused by P.vivax, P.ovale, P. malariae and also sensitive to chloroquine P.falciparum (treatment and prevention);
Rheumatological diseases: rheumatoid arthritis, systemic lupus erythematosus;
Erythrocyte forms (schizonts) P.vivax, P.ovale, P.malaria. P.vivax showed a decrease in sensitivity in New Guinea, Indonesia, Myanmar (Burma), Vanuatu. P.falciparum sensitivity is retained only in certain regions (some countries in the Caribbean, Central America, the Middle East, Egypt).
Pathogenic amoebae are also sensitive to Chloroquine.
Medication is quickly and almost completely absorbed into the digestive tract after use. Bioavailability is practically independent from food intake. The maximum concentration in the blood is developed in 3.5 hours after ingestion and 30 minutes after parenteral (IV, IM, SC) administration. Binding to plasma proteins is 50-65%. It passes through the placenta and penetrates into breast milk. It is mainly metabolised in the liver, with one of the metabolites moderately active against P.falciparum.
Unwanted reactions are pretty rare during the treatment and prevention of malaria. Usually they develop during prolonged use, and patients with rheumatological diseases are more sensitive to them. They may include:
Abdominal pain, anorexia;
Tiredness, inhibition, psychosis;
Rash or itching;
Hemolytic anemia with a deficiency of glucose-6-phosphate dehydrogenase in erythrocytes;
Keratopathy and retinopathy.
It is possible to have destruction of the retina with irreversible visual impairment, especially under the influence of sunlight. Prevention involves avoiding direct sunlight, trying to be periodically examined by an ophthalmologist.
Hypersensitivity to Chloroquine;
During pregnancy and lactation Chloroquine should be prescribed only by a healthcare provider and only after thorough investigation of possible benefits and risks.
Symptoms of overdose include severe headache, dizziness, abdominal pain, severe weakness, sudden drop in blood pressure, arrhythmia, sudden loss of vision, respiratory distress and convulsions. If there is an overdose, the following measures should be taken: gastric lavage using activated charcoal; drugs that increase the acidity of urine (ammonium chloride).