Harvey's Garden

Antiparasitic drugs

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Antiprotozoals

  • Metronidazole:
    • Treats: Giardia lamblia, Entamoeba histolytica (amebiasis, liver abscess), Trichomonas vaginalis. (Remember GET on the Metro). Also anaerobic bacteria.
    • MoA: Forms toxic free radicals.
    • Side Effects: Disulfiram-like reaction with alcohol, metallic taste.
  • Antimalarials:
    • Chloroquine: Treats sensitive Plasmodium species. (Side Effect: Retinopathy with long-term use).
    • Mefloquine: For chloroquine-resistant malaria; prophylaxis. (Side Effect: Neuropsychiatric disturbances).
    • Atovaquone-Proguanil: For chloroquine-resistant malaria; prophylaxis.
    • Artemisinins (e.g., Artesunate): For severe P. falciparum malaria (often IV).
    • Primaquine: Kills hypnozoites of P. vivax & P. ovale (liver stages). (Side Effect: Hemolysis in G6PD deficiency – must test!).
  • Pyrimethamine (+ Sulfadiazine):
    • Treats: Toxoplasma gondii, Cystoisospora belli.
    • MoA: Inhibits folate synthesis. (Give with leucovorin).
    • Side Effect: Bone marrow suppression.
  • Nitazoxanide:
    • Treats: Cryptosporidium, Giardia.
  • Sodium Stibogluconate:
    • Treats: Leishmania spp. (Side Effect: Cardiotoxicity).
  • Nifurtimox/Benznidazole:
  • Suramin/Melarsoprol/Pentamidine:
    • Treats: Trypanosoma brucei (African Sleeping Sickness). Melarsoprol for CNS involvement (toxic).

Antihelminthics

  • Benzimidazoles (Albendazole, Mebendazole):
    • Treats (Broad Spectrum): Enterobius (pinworm), Ascaris (roundworm), Trichuris (whipworm), Hookworms (Ancylostoma, Necator). Albendazole also for Strongyloides, neurocysticercosis (Taenia solium larvae), hydatid cysts (Echinococcus).
    • Helminths NOT well treated by typical benzimidazoles
      • Trematodes (Flukes): Such as Schistosoma (blood flukes) and liver/lung flukes.
        • Better drug: Praziquantel.
      • Adult Cestodes (Intestinal Tapeworms): Such as Taenia saginata (beef) or Diphyllobothrium latum (fish).
        • Better drug: Praziquantel. (Albendazole is used for larval tapeworms like neurocysticercosis).
      • Certain Filarial Nematodes: For conditions like River Blindness (Onchocerca) or Loiasis (Loa loa), and for rapidly clearing microfilariae.
        • Better drugs: Ivermectin or Diethylcarbamazine (DEC) are often primary.
    • MoA: Inhibits microtubule polymerization.
    • Side Effects: Generally few; Albendazole: possible liver enzyme elevation, pancytopenia (with high dose/long use). Mebendazole: teratogenic.
  • Praziquantel:
    • Treats: Trematodes (flukes) like Schistosoma, Clonorchis, Paragonimus; Cestodes (tapeworms) like Taenia spp. (intestinal), Diphyllobothrium.
    • MoA: Increases calcium permeability in worms leading to paralysis.
  • Ivermectin:
    • Treats: Strongyloides stercoralis (drug of choice), Onchocerca volvulus (River blindness). Also scabies, lice.
    • MoA: Activates glutamate-gated Cl- channels (paralysis).
    • Side Effect: Mazzotti reaction (in onchocerciasis).
  • Pyrantel Pamoate:
    • Treats: Pinworms, roundworms, hookworms.
    • MoA: Depolarizing neuromuscular blocker (paralysis).
  • Diethylcarbamazine (DEC):
    • Treats: Wuchereria bancrofti, Brugia malayi (lymphatic filariasis), Loa loa.
    • Side Effect: Reactions to dying microfilariae.

Ectoparasiticides

  • Permethrin:
    • Treats: Scabies, Lice.
    • MoA: Neurotoxin (Na+ channel blocker).
  • Ivermectin (Oral): Alternative for scabies, lice.

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