Infection: Antiprotozoal drugs Flashcards
Metronidazole is the drug of choice for acute invasive amoebic dysentery since it is very effective against vegetative forms of Entamoeba histolytica in ulces. What is an alternative which is also very effective?
Tinidazole.
Metronidazole and tinidazole are also effective against amoeba which may have migrated to the liver. Treatment with metronidazole (or tinidazole) is followed by a 10-day course of what?
Diloxanide furoate.
Diloxanide furoate is the treatment of choice for asymptomatic patients with E.histolytic cysts in the faeces, why is this?
Metronidazole and tinidazole are relatively ineffective against this.
What is the usual course of diloxanide furoate?
10 days, given alone for chronic infections or following metronidazole or tinidazole treatment.
When is aspiriation of an amoebic abscess indicated?
Where it is suspected that it may rupture or where there is no improvement after 72 hours of metronidazole; the aspiration may need to be repeated.
Aspiration aids penetration of metronidazole and, for abscesses with more than 100ml of pus, if carried out in conjuction with drug therapy, may reduce the period of disability.
Diloxanide furoate is not effective against hepatic amoebiasis, why then is a 10-day course given at completion of metronidazole or tinidazole treatment?
To destroy any amoebae in the gut.
What is the treatment of choice for trichomonas vaginalis infection?
Metro, tini if not effective.
What are the three treatment options for Giardia lamblia infections?
Metronidazole: treatment of choice.
Alternatives are tinidazole or mepacrine hydrochloride.
Cutaneous leishmaniasis frequently heals spontaneously but if skin lesions are extensive or unsightly, treatment is inidicated with
Sodium stibogluconate, an organic pentvalent antimony compound.
Amphotericin is used with or after an antimony compound (sodium stibogluconate etc.) for visceral leishmaniasis unresponsive to the antimonial alone, how can side effects be reduced?
Use of liposomal amphotericin (AmBisome).
Most infections caused by Toxoplasma gondii are self-limiting and treatment is not necessary. What are the two exemptions?
Eye involvement (toxoplasma choroidoretinitis) Those who are immunocompromised.
The treatment for toxoplasmosis encephalitis, a common complication of AIDs.
Pyrimethamine and sulfadiazine, given for several weeks.
What mech of action does pyrimethamine have?
Folate antagonist, adverse reactions common, folinic acid supplements needed and weekly blood counts.
An alternative to the usual treatment for toxoplamosis encephalitis (pyrimethamine and sulfadiazine for several weeks) are combinations of pyrimethamine with what?
Clindamycin or clarithromycin or azithromycin.
