Treatment Guidelines for Plasmodium vivax Malaria
Blood‑Stage (Schizonticidal) Therapy
- First‑line therapy for chloroquine‑sensitive P. vivax is oral chloroquine 25 mg/kg given over 3 days, followed by primaquine 15 mg (base) daily for 14 days in adults; a quantitative G6‑PD test must be performed before primaquine to avoid life‑threatening hemolysis. (CDC) [1][2]
- In regions without documented chloroquine resistance, chloroquine remains the preferred first‑line agent. (CDC) [1][2]
- Adult chloroquine dosing: 600 mg base initially, then 300 mg at 6 h, 24 h, and 48 h (total ≈1,500 mg salt or 25 mg/kg).** (CDC) [1][2]
- Pediatric chloroquine dosing: 10 mg/kg at time 0, 10 mg/kg at 24 h, and 5 mg/kg at 48 h (total 25 mg/kg).** (CDC) [1][2]
- Pregnant women: receive the same chloroquine regimen as adults; chloroquine is considered safe throughout pregnancy.** (CDC) [1][3]4
- In areas with widespread chloroquine resistance (e.g., Papua New Guinea, Indonesia, Southeast Asia), artemisinin‑based combination therapies (ACTs) are recommended as alternatives. (CDC) [2][5]
- ACT options:
Radical Cure (Hypnozoite Eradication)
- Primaquine regimen for patients with normal G6‑PD activity: 15 mg base (30 mg phosphate) once daily for 14 days in adults; 0.3 mg/kg/day for 14 days in children.** (CDC) [1][2]
- Contraindication: Primaquine must not be used in individuals with severe G6‑PD deficiency (e.g., Mediterranean variant) because of high risk of severe hemolysis.** (CDC) [1][4]6
- Intermediate G6‑PD deficiency (30–70 % activity, A‑ variant): weekly primaquine 0.75 mg/kg (max 45 mg) for 8 weeks with close monitoring.** (CDC) 2
- Safety warning for Asian populations with high prevalence of severe G6‑PD deficiency: primaquine should never be administered for more than 5 days without a confirmed G6‑PD test.** (CDC) [1][4]6
- Tafenoquine (single‑dose radical cure): 300 mg administered once to patients ≥16 years of age.** (CDC) 2
- Tafenoquine requires a quantitative G6‑PD test showing ≥70 % activity (or ≥6.1 U/g Hb) before use. (CDC) 2
- Tafenoquine contraindications: pregnancy, lactation, age < 16 years, and any degree of G6‑PD deficiency.** (CDC) 2
G6‑PD Testing and Decision Pathway
- Quantitative G6‑PD testing is mandatory before prescribing any 8‑aminoquinoline (primaquine or tafenoquine). (CDC) [1][4][6][2]
- Patients with normal G6‑PD activity (≥70 %): eligible for 14‑day primaquine course or single‑dose tafenoquine.** (CDC) 2
- Patients with intermediate G6‑PD activity (30–70 %): receive weekly primaquine 0.75 mg/kg for 8 weeks with monitoring.** (CDC) 2
- Patients with severe G6‑PD deficiency (<30 % activity or Mediterranean variant): treat blood‑stage infection with chloroquine (or appropriate ACT) only; do not give primaquine or tafenoquine.** (CDC) [1][4]2
Special Populations
Pregnancy
- Blood‑stage treatment: chloroquine is safe and should be administered aggressively.** (CDC) [1][3]4
- Radical cure: primaquine is contraindicated throughout pregnancy.** (CDC) [4][2]
- Management strategy: give weekly chloroquine prophylaxis (300 mg base) throughout pregnancy and continue until after delivery, when radical cure can be considered.** (CDC) 4
- If chloroquine‑resistant infection is suspected: artemether‑lumefantrine is safe in the second and third trimesters and may be used in the first trimester when no other options exist.** (CDC) 5
Lactation
- Primaquine: contraindicated during breastfeeding, except when the infant is older than 1 month and has normal G6‑PD activity.** (CDC) 2
- Tafenoquine: contraindicated during lactation.** (CDC) 2
Children
- Chloroquine: weight‑based dosing totaling 25 mg/kg over 3 days.** (CDC) [1][2]
- Primaquine: 0.3 mg/kg/day for 14 days in children ≥6 months with normal G6‑PD activity.** (CDC) [1][2]
- Tafenoquine: not approved for children younger than 16 years.** (CDC) 2