What are the side effects of malaria treatment?

​What is CHLOROQUINE? Chloroquine is an antimalarial drug. Chloroquine toxicity occurs with large doses like those taken by Eric. Common side effects are nausea, abdominal pain, pruritus, vertigo, headache, and visual disturbances. Rare adverse effects include psychotic episodes, anxiety, personality changes, seizures, blood dyscrasias. What is PRIMAQUINE? Primaquine is an antimalarial drug. It is used to prevent relapse of P. vivax malaria. Common side effects are abdominal pain, nausea and vomiting, dizziness, headache, leucocytosis (increase of white blood cells as sign of infection). Rare adverse effects include hypertension, arrhythmias, anaemia, leucopenia, agranulocytosis (with doses 120 mg daily). Most people take malaria treatment and do not experience major side effects, ma sometimes these side effects do occur. It is important to speak to your doctor if you do have major side effects. Also, you should not take primaquine if you have glucose-6-phosphate dehydrogenase (G6PD) enzyme deficiency.

Eric is 36 years old. He lives in Singapore but was born in Malaysia. He went to Malaysia for 3 weeks to visit his parents. But after his return, he was admitted in the Emergency Department (ED) with 2 days of fever, chills, and bouts of diarrhea. Eric did not take any prophylaxis for malaria and was infected with Plasmodium vivax, a parasite that causes a severe form of malaria that can result in death if not treated. He was given CHLOROQUINE 1 g, then 500 mg 6 hours later and finally 500 mg at 24 and 48 hours. After completing the chloroquine regimen, Eric took PRIMAQUINE 52.6 mg/day for 14 days. However, a day later Eric went back to ED with abdominal pain, severe headache, vomiting, and a bitter taste in the mouth. Did Eric experience the toxicity of antimalarials? Eric' stomach upset, severe headache and bitter taste are the usual side effects of chloroquine preparations. Primaquine after the course of chloroquine will also cause abdominal cramps, but this may be relieved by taking antimalarials with food.

​References Koda-Kimble, Mary Anne. Applied Therapeutics: The Clinical Use of Drugs. 9th ed., Lippincott Williams & Wilkins, 2009. Buckley, Nick, ed. Australian Medicines Handbook 2019. Australian Medicines Handbook, 2019.