Flashcards in anti parasite drugs; antivirals Deck (18):
blocks detoxification of heme into hemozoin. heme accumulates and is toxic to plasmodia
treast plasmodial species other than P. falciparum. doesn't work for P falciparum becasue of a membrane pump that decreases the intracellular concentration of the drug (falciparum should be treated with artemether/lumefantrine or atovaquone/proguanil).
zanamivir: mechanism and clinical use
inhibits flu neuraminidase: decreases the release of progeny virus.
used to treat and prevent flu A and B
oseltamivir also works this way
ribavirin: mechanism and clinical use
inhibits synthesis of guanine nucleotides by competitively inhibiting inosine monophosphate dehydrogenase.
used for RSV and hepC
hemolytic anemia, severe teratogen
acyclovir: others, mechanism
others includ famciclovir, valacyclovir. this drug is monophosphorylated by HSV/VSV thymidine kinase and not phosphorylated in uninfected cells, so there are few adverse effects. it is a guanosine analog that inhibits viral DNA pol by chain termination.
acyclovir: use, considerations
used for HSV and VZV; weakly useful against EBV. no activity against CMV. no effect on latent forms of HSV and VZV. valacyclovir is a prodrug of acyclovir with better oral availability
toxicity and resistance for acyclovir
can cause crystalline nephropathy and acute renal failure. resistance by mutated viral thymidine kinase.
5' monophsphate formed by a CMV viral kinase. this is a guanosine analog. it preferentially inhibits viral DNA pol.
ganciclovir use and resistance
CMV, esp. in immunocompromised pts. valganciclovir is a prodrug with better oral availability. resistance by mutated CMV DNA pol or lack of a viral kinase
leukopenia, neutropenia, thrombocytopenia, renal toxicity. more toxic than acyclovir
viral DNA pol inhibitor that binds to the pyrophospate binding site of the enzyme. doesn't require viral kinase activation. resistance by mutated DNA pol.
CMV retinitis in immunocompromised when ganciclovir fails. good for asyclovir resistant HSV.
toxicit of foscarnet
preferentially inhibits viral DNA pol. doesn't require phosphorylation by a viral kinase.
CMV retinitis in immunocompromised pts; acyclovir resistant HSV. long half life.