harifaroosh - antiparasitic agents

parasite — definition

• any living thing that lives in (endoparasite) or an (ectoparasite) another living organism is called a parasite

• parasites obtain food and/or shelter form the host and contribute nothing to its welfare

• some parasites cause irritation and interference with bodily functions, others destroy host tissues and release toxins into the body, thus impairing health and causing disease

protozoal infections

• amebiasis

• giardiasis

• trichomoniasis

• leishmaniasis

• malaria

• schistosomiasis

• trypanosomiasis

• toxoplasmosis

amebiasis

• disease of large intestine caused by Entamoeba histolytica

• two forms:

  • motile trophozoite form

  • dormant cyst form (encased by a chitinous wall)

amebiasis — symptoms

• intermittent diarrhea (foul smelling loose/watery stools)

• tenderness and enlargement of liver (with extra intestinal form) to acute amebic dysentery

• many pts - no symptoms - organism remains in body as commensal organism

• can invade liver through the bloodstream

amebiasis — treatment

• luminal infections —> use:

  • iodoquinol (Yodoxin)

  • dilaxanide furoate (Furamide)

  • paromomycin (Humatin)

• tissue infections —> use:

  • metronidazole (Flagyl)

  • dehydroemetine or chloroquine

giardiasis

• caused by Giardia Lambia

  • enteric protozoan found in small intestine

• 2 forms: motile trophozoite form, infectious cyst form

• cyst form- can be deposited in water - contaminated water infects man

• trophozoite - if expelled from GI, will not survive

giardiasis — symptoms

may be asymptomatic or develop:

• watery diarrhea

• abdominal cramps

• distention and flatulence

• anorexia

• nausea and vomiting

giardiasis — treatment

antibiotics:

• metronidazole (Noritate)

• tinidazole (Tindamax)

• nitazoxanide (Alinia)

*in pregnancy use paromomycin

trichomoniasis

• caused by Trichomonas Vaginalis

• flagellated protozoan, exists only in trophozoite form

• infects vagina, urethra, prostate — so the disease is considered a venereal infection

trichomoniasis — symptoms

• in males:

  • asymptomatic

• in females:

  • vaginitis

  • profuse discharge which is foul smelling

  • burning and soreness upon urination

  • vulvar itching

trichomoniasis — treatment

metronidazole and tinidazole

helminth infections

• cestode

• nematode

• trematode

hookworm

• caused by Ancylostoma duodenale or Nector americanus

• infection of small intestine

hookworm — symptoms

minimal:

• intestinal inflammation

• progressive iron-deficiency anemia

hookwork — treatment

Mebendazole (Vermox) — alternative agent = albendazole

• these agents bind β-tubulin in the worm and prevent microtubule polymerization

• they also inhibit glucose uptake by the worms

ascariasis (roundworm)

• caused by giant roundworm Ascaris lumbricoides

• found worldwide where sanitation is poor

ascariasis (roundworm) — symptoms

• cough, fever, pneumonitis (during migration through lungs)

• abdominal discomfort/obstruction

• vomiting

enterobiasis

• caused by pinworm

• found worldwide, including developed world

enterobiasis — symptoms

minimal:

• perianal pruritus (mainly at night)

enterobiasis — treatment

Mebendazole (Vermox)

• alternative agent = albendazole

taenia solium (tapeworm)

• cysticercosis: eat undercooked pork, eggs mature into adult tapeworm that infect jejunum

• neurocysticercosis: larvae penetrate bloodstream to infect CNS, muscles, eyes and skin

taenia solium (tapeworm) — symptoms

minimal until infection of tissues

taenia solium (tapeworm) — treatment

• cysticercosis is typcially NOT treated (manage symptoms — seizures)

• tissue infections are managed, not often treated

• cysts can be surgically removed

• live worms treated with albendazole or praziquantel

• praziquantel paralyzes both adult and larvae in a single dose

  • AE: nausea, headache, dizziness, and drowsiness

ectoparasitic infections

scabies and pediculosis (lice)

• treatment of theses is with topical permethrin

  • 1% permethrin (Nix) for lice

  • 5% pemethrin (Elimite) for scabies

  • acts as an insecticide, one treatment is typically sufficient

iodoquinol — brand name

Yodoxin

dilaxanide fuorate — brand name

Furamide

paromomycin — brand name

Humantin

metronidazole — brand name

Flagyl or Noritate

tinidazole — brand name

Tindamax

nitaxozanide — brand name

Alinia

mebendazole — brand name

Vermox

1% permethrin — brand name

Nix

5% permethrin — brand name

Elimite