Malaria Treatment Medications

Malaria is an infectious disease caused by the Plasmodium parasite, transmitted through Anopheles mosquitoes. Currently, numerous medications are employed to treat malaria, each exhibiting distinct mechanisms of action, advantages, disadvantages, and indications.

1. 4-Amino-quinoline Group:

• Chloroquine:

• Action: Eliminates asexual forms within red blood cells of Plasmodium species (except P. falciparum), with moderate efficacy against gametocytes of all species except P. falciparum, and no effect on hypnozoites.

• Advantages: More effective against certain species than quinine, less toxic, shorter treatment duration (3 days compared to 7 days for quinine).

• Adverse Effects: Generally well-tolerated, with few side effects. However, it can induce nausea, vomiting, abdominal pain, diarrhea, headache, dizziness, rash, and itching. High doses can cause blood, vision, and hearing toxicity, hair loss, skin pigmentation changes, hypotension, and seizures.

• Indications: Typical malaria due to P. vivax and P. malariae in normal individuals and pregnant women, prophylaxis for those entering malaria-endemic areas, elimination of extraintestinal amoebae, and certain autoimmune diseases.

• Contraindications: Hypersensitivity to the drug, psoriasis, porphyrin metabolism disorders, history of epilepsy, mental disorders.

• Precautions: Liver and kidney disease, G6PD deficiency, hearing and vision disorders, hematological, neurological disorders, alcohol dependence.

• Quinine:

• Action: Rapid and potent elimination of asexual forms within red blood cells of all Plasmodium species, killing gametocytes EXCEPT P. falciparum. Its mechanism of action is similar to chloroquine.

• Adverse Effects: Strong gastrointestinal irritation, nausea, vomiting, vasodilation, heart inhibition leading to hypotension, hemolysis (G6PD deficiency), leukopenia, decreased prothrombin, hypoglycemia, decreased visual acuity, blurred vision, color disturbances, decreased hearing, deafness, neurological stimulation, delirium, increased uterine contractions (potentially causing miscarriage, birth defects), sterile abscess at injection site, and thrombophlebitis.

• Characteristics of Quinine Syndrome: Headache, vomiting, dizziness, tinnitus, visual disturbances.

• Indications: Alternative medication (2nd line drug) for typical malaria when preferred treatment options are ineffective or relapse occurs within 14 days, severe malaria (when artesunate injection is unavailable), malaria in pregnant women: typical malaria due to P. falciparum in the first trimester, malaria in pregnant women with chloroquine resistance.

• Contraindications: Hypersensitivity to the drug, hearing and vision disorders, hemolysis, anemia.

• Precautions: Liver and kidney disease, G6PD deficiency.

2. 8-Amino-quinoline Group:

• Primaquine:

• Action: Eliminates gametocytes of Plasmodium species => preventing transmission, destroys hypnozoites of P. vivax and P. ovale => preventing relapse.

• Adverse Effects: Low toxicity, relatively safe use, may cause gastrointestinal disturbances, headache, dizziness, arrhythmia, hypertension, hemolysis, leukopenia, methemoglobinemia.

• Indications: Prevention of transmission and relapse in malaria due to P. vivax and P. ovale, can be combined with asexual blood-form killing drugs, prevention of transmission in malaria due to P. falciparum.

• Contraindications: Hypersensitivity to the drug, bone marrow disease, liver disease, history of agranulocytosis, G6PD deficiency, methemoglobin reductase deficiency.

• Precautions: Pregnant women, children under 3 years old.

3. Artemisinin Derivatives:

• Dihydroartemisinin:

• Characteristics: Poorly water-soluble, administered orally or rectally.

• Artesunate:

• Characteristics: Water-soluble, administered orally, intramuscularly, intravenously.

• Artemether, Arteether:

• Characteristics: Oil-soluble, administered intramuscularly.

• General Action:

• Eliminates asexual forms within red blood cells, including chloroquine-resistant P. falciparum.

• Possesses an effect on gametocytes => preventing transmission.

• Derivatives have better efficacy and bioavailability than artemisinin.

• High efficacy, rapid action.

• High relapse rate.

• Adverse Effects: Low toxicity, relatively safe use, may cause gastrointestinal disturbances, headache, dizziness, blurred vision, bradycardia, allergy, decreased BCHTT, elevated transaminase enzymes. Rectal administration can cause irritation, burning, abdominal pain, and diarrhea.

• Indications: Typical malaria due to P. falciparum, severe malaria (first-line choice is artesunate injection, more effective and safe than quinine injection), typical malaria due to P. falciparum in pregnant women > 3 months.

• Contraindications: Pregnant women in the first trimester, children <5 kg.

Note:

• Medication use should strictly adhere to a doctor’s prescription.

• Adherence to correct dosage and duration is crucial for optimal treatment outcomes.

• Inform your doctor about your medical history, drug allergies, and current medications to avoid unintended side effects.

• Adhering to malaria prevention measures, such as mosquito nets, mosquito control, and wearing long-sleeved clothing, is essential for protecting your own health and the community.

RR:

• RR stands for resistance rate.

• The resistance rate to malaria treatment medications is increasing, making the selection of appropriate medications critically important.

• Health agencies regularly monitor and update resistance information to provide appropriate treatment guidance.

Conclusion:

Selecting a malaria treatment medication depends on numerous factors, including the Plasmodium species causing the infection, the patient’s health status, and drug resistance levels. Consulting a physician is absolutely essential.