Parasitic%20infections Treatment
Pharmacotherapy
Recommended Therapy For Protozoan Parasites | ||
Pathogen | Drug | |
Preferred Agents | Alternative Agents | |
Cryptosporidium sp (Cryptosporidiosis) | Nitazoxanide or Paromomycin + Azithromycin |
- |
Entamoeba histolytica (Amoebiasis)
|
Iodoquinol or Paromomycin | Diloxanide furoate or Etofamide |
E histolytica (Amoebiasis)
|
Metronidazole or Tinidazole | Ornidazole or Secnidazole |
E histolytica (Amoebiasis)
|
Metronidazole or Tinidazole | Chloroquine or Secnidazole |
Giardia lamblia (Giardiasis) | In most immunocompetent patients, giardiasis is self-limiting & does not require treatment. In nonendemic areas, asymptomatic carriers of giardiasis are treated | |
Metronidazole | Albendazole, Furazolidone, Nitazoxanide, Ornidazole, Paromomycin, Quinacrine, Secnidazole or Tinidazole |
Recommended Therapy For Helminths | ||
Pathogen | Drug | |
Preferred Agents | Alternative Agents | |
Cestodes (Tapeworms) | ||
Taenia saginata, Taenia solium, Diphyllobothrium caninum, Diphyllobothrium latum | Praziquantel | Niclosamide |
Nematodes (Roundworms) | ||
Ascaris lumbricoides (Ascariasis) | Albendazole, Ivermectin, Mebendazole or Nitazoxanide | Levamisole, Piperazine or Pyrantel pamoate |
Ancylostoma duodenale, Necator americanus (Ancylostomiasis) (Hookworms) | Albendazole, Mebendazole or Pyrantel pamoate | Levamisole |
Capillaria philippinensis (Capillariasis) | Mebendazole | Albendazole |
Enterobius vermicularis (Pinworm or Threadworm) | Albendazole, Mebendazole or Pyrantel pamoate | Piperazine |
Strongyloides stercoralis (Strongyloidiasis) | Albendazole, Ivermectin, Mebendazole or Thiabendazole | - |
Trichuris trichiura (Whipworm) | Mebendazole | Albendazole, Ivermectin or Nitazoxanide |
Trematodes (Flukes) | ||
Clonorchis sinensis (Oriental liver fluke) | Albendazole orPraziquantel | - |
Fasciola hepatica (Fascioliasis) | Bithionol or Triclabendazole | Nitazoxanide |
Fasciolopsis buski, Heterophyes heterophyes Metagonimus yokogawai (Intestinal flukes) | Praziquantel | - |
Opisthorchis viverrini (Southeast Asian liver fluke) | Albendazole or Praziquantel | - |
Paragonimus westermani (Lung flukes) | Praziquantel | Bithionol |
Schistosoma haematobium | Praziquantel | Metrifonate |
Schistosoma japonicum | Praziquantel | - |
Schistosoma mansoni | Praziquantel | Oxamniquine |
Drugs for Treatment of Amoebiasis
Luminal Amoebicides
- Eg Diloxanide furoate, Iodoquinol, Paromomycin
- These agents are effective in treating organisms in the bowel lumen
- May be used in patients w/ asymptomatic E histolytica infection
- Recommended for asymptomatic cyst passers
- To avoid the risk of developing invasive disease
- To prevent secondary spread
- When asymptomatic cyst carriage persists after treatment for amoebic dysentery or liver abscess, further treatment w/ a luminal amoebicide is mandatory, otherwise relapse is frequent
- Paromomycin
- Acts directly on amoeba w/ antibacterial activity against normal & pathogenic organisms in GI tract; binds to 30s ribosomal subunits interfering w/ bacterial protein synthesis
- Temporarily eliminates diarrhea in human immunodeficiency virus (HIV) patients who have cryptosporidiosis
- May also be used in treatment of cryptosporidiosis & giardiasis
Tissue Amoebicides
- Eg Chloroquine & Nitroimidazole derivatives (Metronidazole, Nimorazole, Ornidazole, Secnidazole & Tinidazole)
- These agents are effective in treating invasive amoebiasis but are less effective in treating organisms in the bowel lumen
- Chloroquine binds & inhibits DNA & RNA polymerase; it also raises parasite’s internal pH, restricting its growth
- Nitroimidazole derivatives cause damage to parasite DNA helical structure resulting in strand breakage & impaired template function
Other Antiprotozoan Drugs
- Eg Furazolidone, Nitazoxanide, Quinacrine
Furazolidone
- Used for the treatment of giardiasis
- Furazolidone is as effective as Metronidazole in the treatment of giardiasis
- Action: Causes damage to intracellular components
Nitazoxanide
- Action: Inhibits growth of sporozoites & oocysts of Cryptosporidium sp & trophozoites of G lamblia
Quinacrine (Mepacrine)
- Action: Suggested action is binding to parasite DNA thereby inhibiting RNA transcription & protein translation
Anthelminthic Drugs
Albendazole
- Has an exceptionally broad spectrum of antiparasitic activity
- Widely used for intestinal nematode infections
- Decreases ATP production in worms
Bithionol
- Preferred agent for F hepatica
- Release of worm antigens may cause reactions eg urticaria, photosensitivity reactions & GI symptoms
Ivermectin
- As effective as Thiabendazole against S stercoralis but has fewer untoward effects
- Action: Causes hyperpolarization of muscle & nerve cells of parasite leading to paralysis
Levamisole
- Action: Causes muscle paralysis in susceptible worms
Mebendazole
- Widely used for treatment of intestinal nematodes
- Poorly absorbed from the GI tract resulting in a low frequency of side effects
- Action: Blocks glucose & nutrient uptake irreversibly in susceptible worms
Metrifonate
- Alternative to Praziquantel in the treatment of S haematobium infection
- Action: Inhibits acetylcholinesterase
Niclosamide
- Action: Causes necrosis of head & segments of tapeworms
Oxamniquine
- Used only for S mansoni infection
- Action: Causes blood fluke to transfer from mesenteric veins to the liver where the males are retained; females return to mesentery but cannot release eggs anymore
Piperazine
- Action: Blocks acetylcholine effects at neuromuscular junction causing muscle paralysis
Praziquantel
- Highly effective against all Schistosoma sp that infect humans, adult & larval form of cestodes
- Drug of choice for liver flukes
- Action: Increases cell permeability in helminths w/ loss of intracellular calcium & paralysis of musculature
- Drug resistance is a possibility, especially in countries practicing mass chemotherapy as a control measure
Pyrantel pamoate
- Used for the treatment of intestinal nematodes (roundworm, hookworm & pinworm)
- Action: Blocks acetylcholine effects at neuromuscular junction causing muscle paralysis
Thiabendazole
- Active against many intestinal adult nematodes & larval forms in tissues
- High frequency of untoward effects & the availability of alternative agents have limited its usefulness
Non-Pharmacological Therapy
Adequate Hydration & Nutrition
- Patients w/ parasitic infections frequently suffer from malabsorption, vomiting & diarrhea, resulting in malnutrition
- Ensure that patient’s nutritional & hydration status are maintained at acceptable levels
Replacement of Fluid & Electrolyte Losses
- Vomiting & diarrhea result in fluid & electrolyte losses, mainly Na & K
Blood Transfusion & Treatment w/ FeSO4
- These measures may be necessary in hookworm infections which may cause severe anemia