What are the recommended treatment regimens for uncomplicated and severe malaria, including special considerations for pregnancy, G6PD deficiency, and children?

Malaria Management

Uncomplicated Malaria Treatment

For uncomplicated chloroquine-resistant P. falciparum malaria, artemisinin-based combination therapy (ACT) is the first-line treatment, with artemether-lumefantrine (AL) being the preferred regimen in most settings. 1

Standard Regimens for Uncomplicated Malaria

For P. falciparum (chloroquine-resistant):

• Artemether-lumefantrine (AL): Given at 0,8,24,36,48, and 60 hours

  • 5-<15 kg: 1 tablet per dose
  • 15-<25 kg: 2 tablets per dose
  • 25-<35 kg: 3 tablets per dose
  • ≥35 kg: 4 tablets per dose 2

• Alternative: Atovaquone-proguanil (Malarone) for 3 days

  • 5-8 kg: 2 pediatric tablets daily
  • 9-10 kg: 3 pediatric tablets daily
  • 11-20 kg: 1 adult tablet daily
  • 21-30 kg: 2 adult tablets daily
  • 31-40 kg: 3 adult tablets daily

  • 40 kg: 4 adult tablets daily 2

For P. vivax, P. ovale, and P. malariae (chloroquine-sensitive):

• Chloroquine: Total dose of 25 mg base/kg over 3 days
  • Adults: 600 mg, 600 mg, and 300 mg at 0,24, and 48 hours 3
  • Children: 10 mg/kg, 10 mg/kg, and 5 mg/kg at 0,24, and 48 hours 3

Important caveat: For P. vivax from Papua New Guinea, Indonesia, or Sabah where chloroquine resistance exceeds 10%, use ACT instead 1. Dihydroartemisinin-piperaquine shows superior efficacy over chloroquine or AL for P. vivax 1.

Preventing Relapse in P. vivax and P. ovale

After blood-stage treatment, primaquine is essential to eliminate liver hypnozoites:

• Adults: 15 mg daily for 14 days 3
• Children: 0.3 mg/kg/day for 14 days 3

Critical G6PD consideration: In populations with severe G6PD deficiency (notably Asians), primaquine should NOT be administered for more than 5 days due to risk of life-threatening hemolysis 3. Whenever possible, test for G6PD deficiency before primaquine administration 3. Quantitative testing is particularly important in females to distinguish deficiency from intermediate activity 4.

Severe Malaria Treatment

For severe malaria, intravenous artesunate is the treatment of choice and has replaced quinine as the gold standard due to superior mortality reduction. 5

Severe Malaria Regimen

Intravenous artesunate is indicated for:

• Impaired consciousness
• Respiratory distress
• Seizures
• Prostration
• Shock
• Jaundice
• Severe anemia
• Renal impairment
• Acidosis
• Hypoglycemia
• High parasitemia (>5%)

If artesunate is unavailable, use quinine hydrochloride:

• Loading dose: 20 mg salt/kg IV over 4 hours
• Maintenance: 10 mg/kg IV over 4 hours every 8 hours 2
• Omit loading dose if patient received mefloquine prophylaxis in previous 24 hours or treatment dose within 3 days 2

After parenteral therapy and clinical improvement, switch to oral ACT to complete treatment (proguanil with atovaquone, mefloquine, or artemether with lumefantrine) 2.

Post-treatment monitoring: Patients treated with IV artesunate should be closely monitored for hemolysis for 4 weeks after treatment 5. Post-artemisinin delayed hemolysis (PADH) occurs in 1.9-37.4% of patients depending on diagnostic criteria 1.

Special Populations

Pregnancy

Artemether-lumefantrine is now recommended for uncomplicated malaria in the second and third trimesters of pregnancy, and during the first trimester when other options are unavailable. 6

This 2018 CDC guideline update represents a major shift from previous restrictions, based on strong evidence demonstrating AL's safety and efficacy throughout pregnancy 6.

Treatment by trimester:

First trimester:

• Preferred: Quinine plus clindamycin (if available) 6
• Alternative: Artemether-lumefantrine when other options unavailable 6

Second and third trimesters:

• First-line: Artemether-lumefantrine 6
• Alternative: Mefloquine or quinine plus clindamycin 6

For chloroquine-sensitive species: Chloroquine is safe throughout pregnancy 3, 7. Pregnant women should be treated aggressively using adult dosing 3.

For severe malaria in pregnancy: IV artesunate is recommended in all trimesters 1, 8.

Critical contraindication: Primaquine is absolutely contraindicated during pregnancy because it may pass transplacentally to a G6PD-deficient fetus and cause hemolytic anemia in utero 7. For pregnant women requiring radical cure, give chloroquine or hydroxychloroquine weekly as suppressive therapy until delivery, then reassess primaquine use postpartum 7, 4. Hydroxychloroquine may be preferred for prolonged use due to better tolerability 4.

Children

Dosing for children follows weight-based regimens as outlined above. Key considerations:

• Seizure management: Follow standard Advanced Paediatric Life Support protocols with lorazepam 0.1 mg/kg IV/IO, repeated once if needed, then paraldehyde 0.4 mg/kg rectally or phenytoin/phenobarbital loading 2
• Do NOT use prophylactic phenobarbital - it increases mortality in cerebral malaria 2
• Chloroquine for children: Mix powder in food/drink to facilitate weekly administration; chloroquine suspension is widely available overseas 7
• Critical safety warning: Antimalarial overdose can be fatal - store in child-proof containers out of reach 7

G6PD Deficiency

G6PD testing is NOT required for single-dose gametocytocidal primaquine (0.25 mg/kg), but IS essential prior to radical cure with primaquine or tafenoquone. 8

For patients with confirmed G6PD deficiency:

• Avoid primaquine for radical cure
• Use chloroquine or hydroxychloroquine for suppressive therapy in P. vivax/P. ovale 4
• Limit primaquine to maximum 5 days if absolutely necessary in populations with severe G6PD deficiency 3
• Quantitative G6PD testing is essential in females to distinguish deficiency from intermediate activity in heterozygotes 4

Common Pitfalls and Caveats

1. Treatment failures with AL: Observational studies from Europe report treatment failures with ACT, possibly related to malabsorption or inadequate lumefantrine levels in higher body weight patients 1. Swiss guidelines recommend extending AL from 3 to 5 days in some cases 1.

2. Southeast Asian resistance: For patients from the Greater Mekong sub-region with high ACT resistance, use atovaquone-proguanil as second-line 1.

3. Quinine monitoring in pregnancy: Pregnant women receiving IV quinine should be monitored carefully for hypoglycemia 3.

4. Avoid oral quinine in children: The bitter taste affects compliance 2.

5. Mefloquine contraindications: Do not use during pregnancy; women of childbearing age taking mefloquine must use reliable contraception during prophylaxis and for 2 months after the last dose 7.

6. Doxycycline in pregnancy: Absolutely contraindicated for prophylaxis due to fetal tooth discoloration and bone growth inhibition 7.

7. Breast-feeding: Small amounts of antimalarials in breast milk are insufficient to protect infants - they require full prophylactic dosing 7.