Common Parasites & First-Line Treatments
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🦠 Common Parasites & First-Line Treatments
| Disease | Causative Agent | Drug of Choice | Dose & Notes |
| Strongyloidiasis | Strongyloides stercoralis | Ivermectin | 200 mcg/kg PO daily × 1–2 days; repeat in 2 wks if chronic |
| Enterobiasis (Pinworm) | Enterobius vermicularis | Albendazole | 400 mg PO single dose; repeat in 2 wks |
| Ascariasis (Roundworm) | Ascaris lumbricoides | Albendazole or Mebendazole | 400 mg PO single dose |
| Hookworm | Ancylostoma duodenale, Necator americanus | Albendazole | 400 mg PO daily × 3 days |
| Trichuriasis (Whipworm) | Trichuris trichiura | Albendazole | 400 mg PO daily × 3 days |
| Taeniasis (Tapeworm) | Taenia saginata, T. solium | Praziquantel | 5–10 mg/kg PO single dose |
| Neurocysticercosis | T. solium (larvae) | Albendazole + Dexamethasone + Anticonvulsant | Albendazole 15 mg/kg/day × 28 days |
| Schistosomiasis | Schistosoma spp. | Praziquantel | 40–60 mg/kg PO divided doses × 1 day |
| Opisthorchiasis/Clonorchiasis | Opisthorchis viverrini, Clonorchis sinensis | Praziquantel | 25 mg/kg PO TID × 1 day |
| Fascioliasis | Fasciola hepatica | Triclabendazole | 10 mg/kg PO; repeat in 12–24 hrs |
| Giardiasis | Giardia lamblia | Metronidazole or Tinidazole | Metronidazole 250 mg PO TID × 5–7 days; or Tinidazole 2 g single dose |
| Amebiasis (Intestinal) | Entamoeba histolytica | Metronidazole then Paromomycin | Metronidazole 500–750 mg TID × 7–10 days, then luminal agent |
| Malaria (P. vivax/ovale) | Plasmodium spp. | Chloroquine + Primaquine | Region-specific chloroquine + Primaquine 15 mg/day × 14 days (G6PD test first) |
| Malaria (P. falciparum) | P. falciparum | ACT (Artemisinin-based) | E.g., Artemether-lumefantrine BID × 3 days |
| Toxoplasmosis | Toxoplasma gondii | Pyrimethamine + Sulfadiazine + Leucovorin | For CNS/systemic infections |
💊 Common Antiparasitic Drugs Summary (Adult Doses)
| Drug | Indications | Dose | Route | Duration |
| Albendazole | Nematodes (Ascaris, Hookworm, Strongyloides, Trichuris) | 400 mg daily | PO | 1–3 days |
| Mebendazole | Same as Albendazole | 100 mg BID × 3 days or 500 mg single dose | PO | As indicated |
| Ivermectin | Strongyloides, Scabies | 200 mcg/kg/day | PO | 1–2 days (repeat PRN) |
| Praziquantel | Tapeworms, Schisto, Clonorchis | 25–60 mg/kg/day | PO | 1 day (divided doses) |
| Triclabendazole | Fasciola | 10 mg/kg PO twice | PO | 1 day |
| Metronidazole | Giardia, Amoeba, Trichomonas | 500–750 mg TID | PO | 5–10 days |
| Tinidazole | Giardia, Amoeba | 2 g single dose | PO | Single |
| Paromomycin | Luminal amoebicide | 25–35 mg/kg/day ÷ TID | PO | 7 days |
| Pyrimethamine | Toxoplasmosis | 200 mg loading, then 50–75 mg/day | PO | Weeks |
| Sulfadiazine | Toxoplasmosis | 1–1.5 g q6h | PO | Weeks |
| Nitazoxanide | Cryptosporidium, Giardia | 500 mg BID | PO | 3 days |
| Chloroquine | P. vivax, P. ovale | 600 mg base, then 300 mg base at 6, 24, 48 hrs | PO | 3 days |
| Primaquine | Liver stage of vivax/ovale | 15 mg base daily | PO | 14 days (test for G6PD first) |
🔔 Critical Clinical Notes
- G6PD test required before Primaquine.
- Avoid Albendazole in the 1st trimester of pregnancy.
- Praziquantel tablets are usually 600 mg → calculate mg/kg!
- CNS Toxoplasmosis needs triple therapy: pyrimethamine + sulfadiazine + leucovorin.
- Neurocysticercosis requires anti-helminth + steroids + seizure prophylaxis.
- Chronic Strongyloidiasis → Ivermectin may require longer or repeated doses.
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