Amoebiasis

AmebiasisClassification of antiamebic drugs1. Tissue Amebicides(a) For both intestinal and extraintestinal amoebiasis:Nitroimidazoles: Metronidazole, Tinidazole, Secnidazole, Ornidazole, SatranidazoleAlkaloids: Emetine, Dehydroemetine(b) For extraintestinal amoebiasis only: Chloroquine2. Luminal amoebicides(a) Amide : Diloxanide furoate, Nitazoxanide(b) 8-Hydroxyquinolines: Quiniodochlor (Iodochlorohydroxyquin, Clioquinol), Diiodohydroxyquin (Iodoquinol)(c) Antibiotics: Tetracyclines, ParomomycinParomomycin is an alternative drug for giardiasis, especially during 1st trimester of pregnancy when metronidazole and other drugs are contraindicated. It has been used in cryptosporidiosis, but efficacy is uncertain. Topically, it may used in trichomonas vaginitis and dermal leishmaniasis. amoebiasis/giardiasis/cryptosporidiosis. Side effects are limited to the g.i.t.; nausea, vomiting, abdominal cramps, diarrhoea; rarely rashes.Paromomycin is an efficacious luminal amoebicide, achieving similar or even better clearing of cysts from stools compared to diloxanide furoate in asymptomatic cyst passers.Good symptomatic relief and cyst clearance is obtained in chronic amoebic colitis. It can be given along with metronidazole in acute amoebic dysentery as well as in hepatic amoebiasis to eradicate the luminal cycle.In India and Africa, parenteral (i.m.) paromomycin is being used in resistant KalaazarAsymptomatic cyst passers are mostly treated with only luminal amoebicide. Chronic cases may require 23 repeated courses in which drugs may be alternated.A tetracycline may be given concurrently with the luminal amoebicide in cases which fail to clear completely.inhibit the bacterial flora with which Entamoebae live symbiotically. Thus, they indirectly reduce proliferation of entamoebae in the colon and are especially valuable in chronic, difficult to treat cases

NitroimidazolesMetronidazoleAnaerobic in A,G, TVAnarobes B Fragilis, Fusobacterium,Clostridium perfringens, Cl. difficile, Helicobacterpylori, Campylobacter, peptococci, Dracunculus medinensis, extraction of the worm from under the skin is facilitated

selectively toxic to anaerobic and microaerophilic microorganismsenters the cell by diffusionits nitro group is reduced to a highly reactive nitro radical which exerts cytotoxicity- inhibit cell mediated immunity, to induce mutagenesis and to cause radiosensitizationattaining therapeutic concentration in vaginal secretion, semen, saliva and CSF.Plasma t is 8 hrs.Anorexia, nausea, metallic taste and abdominal cramps, Loose stoolsglossitis, dryness of mouthHead ache, dizzinessUrticaria, flushing, heat, itching, rashes and fixed drug eruption occur in allergic subjects,Peripheral neuropathy and CNS effects. Seizures have followed very high doses. Leucopenia is likely with repeated courses.ThrombophlebitisContraindicated in neurological disease, blood dyscrasias, first trimester of pregnancy Cautious use in chronic alcoholics. A disulfiram-like intolerancePreferred over vancomycin which may be used in nonresponsive cases, or when the infection recurs; Pseudomembranous enterocolitis due to Cl. difficileTinidazolet is ~12 hr; duration, suited for single dose or once daily therapy. higher cure rates. better toleratedSecnidazole; t of 1729 hoursOrnidazole; t (1214 hr).Satranidazole; t (14 hr).- tolerability:no nausea, vomiting or metallic taste, absence of neurological and disulfiramlike reactions