Malaria Chemoprophylaxis Drugs:
- Chloroquine: No longer recommended due to widespread resistance.
- Mefloquine (Lariam): Weekly, 250 mg; effective against chloroquine-resistant strains.
- Rationale: CDC recommends for areas with mefloquine-sensitive strains.
- Atovaquone-Proguanil (Malarone): Daily, 250/100 mg; well-tolerated, effective against multidrug-resistant strains.
- Rationale: Preferred for travelers to high-resistance regions (e.g., Southeast Asia).
- Doxycycline: Daily, 100 mg; broad-spectrum, but photosensitivity risk.
- Rationale: Alternative for mefloquine-intolerant patients.
- Tafenoquine (Arakoda): Weekly, 200 mg; long half-life, but contraindicated in G6PD deficiency.
- Rationale: Newer option for P. vivax prevention.
- Prevention Rates:
- Atovaquone-Proguanil: ~99% efficacy in clinical trials (Rationale: High barrier to resistance).
- Mefloquine: ~95% efficacy (Rationale: Effective against most resistant strains).
- Doxycycline: ~95% efficacy (Rationale: Broad-spectrum, but not for P. falciparum in some regions).
- Usage Guidelines:
- Start 1–2 weeks before travel (except tafenoquine, which starts 1 day before).
- Continue for 4 weeks post-exposure (except tafenoquine, which is 4 months for P. vivax).
- Caution: G6PD testing required for tafenoquine; avoid mefloquine in psychiatric history.
- Perennial Malaria Chemoprevention (PMC):
- Sulfadoxine-Pyrimethamine (SP): Monthly, 3 doses; used in sub-Saharan Africa.
- Rationale: Cost-effective, but resistance limits efficacy (~50% in some regions).
- Dihydroartemisinin-Piperaquine (DP): Monthly, 3 doses; higher efficacy (~80% in trials).
- Rationale: First-line for seasonal malaria in Sahel.
Key Reference: CDC Yellow Book (2024), WHO Malaria Guidelines (2023).