Antiprotozoal

Antiprotozal drugs

Amoebiasis
Infection occurs when mature cysts are ingested and pass into the colon where they divide into trophozoites; these forms either enter the tissues or reform cysts. Amoebiasis occurs in two forms both of which need treatment:
Bowel lumen amoebiasis
Tissues –invading amoebiasis

Bowel lumen amoebiasis

Is asymptomatic and trophozoites and cysts are passed into the faeces. Treatment is directed at eradicating cysts with a luminal amoebicide; diloxanide furoate is the drug of choice; iodiquinol or paromomycin are alternatives.

Tissues –invading amoebiasis

Gives rise to dysentery hepatic amoebiasis and liver abscess.
A systemically active drug (tissue amoebicide) effective against trophozoites must be used, e.g. metronidazole, tinidazole. Parenteral forms of these are available for patients too ill
Treatment with tissue amoebicides should always be followed by a course of a luminal amoebicide to eradicate the source of the infection

Drugs used against amoebiasis

Metronidazole
Tinidazole
Dehydroemtine
Diloxanide furoate
Iodoquinol


Dehydroemtine
Less toxic than the parent emetine is claimed by some authorities to be the most effective tissue amoebicide
Adverse effects
It cardiotoxic effects
which are generally mild with use for 3–5 days, increase over time and include pain, tenderness, and sterile abscesses at the injection site; diarrhea, nausea, and vomiting; muscle weakness and discomfort

Diloxanide furoate

It is an effective luminal amebicide but is not active against tissue trophozoites
It is used with a tissue amebicide, usually metronidazole, to treat serious intestinal and extraintestinal infections
Adverse effects
Flatulence is common, but nausea and abdominal cramps are infrequent and rashes are rare. The drug is not recommended in pregnancy.

Iodoquinol

It is an effective luminal amebicide that is commonly used with metronidazole to treat amebic infections
It is effective against organisms in the bowel lumen but not against trophozoites in the intestinal wall or extraintestinal tissue
Adverse effects
anorexia, nausea, vomiting, abdominal pain, headache, rash, and pruritus. The drug may increase protein-bound serum iodine, leading to a decrease in measured 131I uptake that persists for months.

Drugs for some protozal infections

Drugs
Infections
Metronidazole, tinidazole
Giardiasis
Sodium stibogluconate
Leishmaniasis
Pyrimethamine with sulfadiazine alternative include pyrimethamine with clindamycin or clarithromycin or azithromycin
toxoplasmosis
Metronidazole or tinidazoleis effective
Trichomoniasis


LEISHMANIASISSodium stibogluconate
Pentavalent antimonials, are generally considered first-line agents for cutaneous and visceral leishmaniasis except in parts of Indina
Adverse effects
Most common are gastrointestinal symptoms, fever, headache, myalgias, arthralgias, and rash. Intramuscular injections can be very painful and lead to sterile abscesses

Drugs for helminthic infections

Levamisole
Mebendazole
Niclosamide
Praziquantel
Pyrantel Pamoate
Albendazole

Levamisole

Paralyses the musculature of sensitive nematodes, which unable to maintain their anchorage ,are expelled by normal peristalsis ,it is well tolerated but may cause
Abdominal pain, nausea, vomitting, headache and
Dizziness.

Mebendazole

Blocks glucose uptake by nematodes
Mild gastrointestinal discomfort may be caused , diarrhea and it should not be used in pregnancy or in children under the 2 years.


Niclosamide
Adult worms (but not ova) are rapidly killed, presumably due to inhibition of oxidative phosphorylation or stimulation of ATPase activity
Infrequent, mild, and transitory adverse events include nausea, vomiting, diarrhea, and abdominal discomfort.laxative is administered to purge the bowel of all dead segments and enhance liberation of the ova.

Praziquantel

is effective in the treatment of schistosome infections of all species and most other trematode and cestode infections, including cysticercosis. The drug's safety and effectiveness as a single oral dose have also made it useful in mass treatment of several infections

Pyrantel pamoate

Depolarises neuromuscular junctions of susceptible nematodes which are expelled in the feces ,poorly
Absorb orally, adverse effect nausea, vomiting, diarrhea.

Drugs for helminthic infections

Drug
Infection

Niclosamide or praziquantel

albendazole
Cestodes (tapworms)
Beef tapeworm (taenia saginata)
Hydatid disease (echinococcus granulosus)


Levamisole, mebendazole
Mebendazole, pyrantel
Ivermectin or thiabendazole

Pyratel or mebendazole

Mebendazole or albendazole
Nematodes (intestinal)
Ascariasis ascaris lumbricoides
Hookworm ancylostoma duodenale
Strongyloidiasis (strongyloides stercoralis)
Threadworm (pineworm) enterobius vermicularis
Whipworm (trichuris trichiuria)

Praziquantel

Schistosomasis (intestinal)
Schistosoma mansoni

Albendazole

Inhibit microtubule synthesis and glucose uptake in nematode,in cestode in hydatid disease,absorb after oral administration,enhanced by ahigh-fat meal.undergos extensive 1st pass metabolism,exc.in bile, used 3 days for nematodal infestation ,3 months in hydatid disease.
adverse effect headache,nausea,
Hepatotoxic,agranulocytosis,convultion,not used in
Pregnant and child under 2 years.