anti amoebic drugs Flashcards
metronidazole effectiveness
Metronidazole, a nitroimidazole is the drug of
choice in the treatment of extraluminal amebiasis. It kills trophozoites but not cysts of E histolytica and effectively eradicates intestinal and extraintestinal tissue infections
kinetics of merronidazole
Oral metronidazole and tinidazole are readily absorbed and permeate all tissues by simple diffusion. Peak plasma concentrations
are reached in 1–3 hours. Protein binding of both drugs is low
(10–20%)
the half-life of unchanged drug is 7.5 hours for metronidazole. Metronidazole and its
metabolites are excreted mainly in the urine. Plasma clearance of
metronidazole is decreased in patients with impaired liver function. The nitro group of metronidazole is chemically reduced in
anaerobic bacteria and sensitive protozoans. Reactive reduction
products appear to be responsible for antimicrobial activity.
Clinical Uses metronidazole
Clinical Uses
1. Amebiasis. DOC for E histolytica.
2. Giardiasis—Metronidazole is the treatment of choice for giardiasis. The dosage for giardiasis is much lower—and the drug
thus better tolerated—than that for amebiasis. Efficacy after a single treatment is about 90%.
3.Trichominiasis—Metronidazole is the treatment of choice. A single dose of 2 g is effective.
POST OPERATIVE ANAEROBIC INFECTION
SYMPTOMATIC FORM OF AMOEBIASIS
ULCERATAIVE GUNGIVITIS /TOOTHACHE
ADRS METRONIDAZOLE
Nausea, headache, dry mouth, or a metallic taste, vomiting, diarrhea, insomnia, weakness, dizziness, thrush, rash, dysuria,
dark urine, vertigo, paresthesias, and neutropenia.
The dosage should be
adjusted for patients with severe liver or renal disease
CI in pregnancy
IODOQUINOL
Iodoquinol (diiodohydroxyquin) is a halogenated hydroxyquinoline. It is an effective luminal amebicide. Pharmacokinetic data are
incomplete but 90% of the drug is retained in the intestine and
excreted in the feces. The remainder enters the circulation, has a
half-life of 11–14 hours, and is excreted in the urine as glucuronides.
NO MAO
EFFECTIVENESS OF IODOQUINOL
It is effective against organisms in the boweL lumen but not against trophozoites in the intestinal wall or
extraintestinal tissues.
IODOQUINOL ADRS
Iodoquinol should be taken with meals to limit gastrointestinal toxicity. It should be used with caution in patients with
optic neuropathy, renal or thyroid disease, or nonamebic hepatic
disease. It is contraindicated in patients with intolerance to iodine.
NEUROTOXICITY OR PERIPHERAL NEUROPATHY
effectiveness fo diloxanide furoate
Diloxanide furoate is a dichloroacetamide derivative. It is an effective luminal amebicide but is not active against tissue trophozoites
ASYMPTOMATIC INFECTION
DILOXANIDE FUROATE
In the gut, diloxanide furoate is split into diloxanide and
furoic acid; about 90% of the diloxanide is rapidly absorbed and
then conjugated to form the glucuronide,excreted in the urine. The unabsorbed diloxanide is the active
antiamebic substance
ADRS OF DILOXANIDE FUROATE
MOST IMP FACTOR
It is used with a tissue amebicide, usually metronidazole, to treat serious intestinal and extraintestinal infections.
.Flatulence is common
EMETINE AND DEHYDRO EMODIN
Emetine, an alkaloid derived from ipecac, and dehydroemetine, a
synthetic analog, are effective against tissue trophozoites of E histolytica
KINETICS OF EMEDIN AND DEHYDROEMDEDIN
The
drugs should be used for the minimum period needed to relieve
severe symptoms (usually 3–5 days) and should be administered
subcutaneously (preferred) or intramuscularly in a supervised setting.
ADRS OF EMETINE AND DEHYDROEMETINE
Dehydroemetine
is preferred because of its somewhat better toxicity profile pain, tenderness, and sterile
abscesses at the injection site; diarrhea, nausea, and vomiting;
muscle weakness and discomfort; and minor electrocardiographic
changes. Serious toxicities include cardiac arrhythmias, heart
failure, and hypotension
CI OF METRONIDAZOLE
Metronidazole has been reported to potentiate the anticoagulant effect of coumarin-type anticoagulants. Phenytoin and phenobarbital may accelerate elimination of the drug, whereas
cimetidine may decrease plasma clearance. Lithium toxicity may
occur when the drug is used with metronidazole. Metronidazole
and its metabolites are mutagenic in bacteria
DOSES OF ALL DRUGS
500 MG TID FOR THREE DAYS (DILOXANIDE FUROATE)
IODOQUINOL + TETRACYCYLINES=650MG+250MG
750 MG TID FOR 5 DAYS (METRONIDAZOLE)
