Tx of viral skin infections Flashcards
topical drugs move in 3 ways to reach their target
- transcellularly
- paracellularly
- via the appendages (hair follicles)
which drugs can be given PO only (3)
famciclovir, valacyclovir, valganciclovir
name the drugs that can be given IV only (2)
cidofovir, foscarnet
name the drugs that can be given IV/PO (2)
ganciclovir, acyclovir
which skin condition requires immediate in hospital IV acyclovir
dermatitis herpatiformes
(HSV infection on top of atopic dermititis
which drugs are pro drugs
valacyclovir–> acyclovir
valganciclovir–> ganctyclovir
famciclovir–>penciclovir
tx for pox family viruses (1)
cidofovir
Tx for varicella zoster (shingles) (3)
acyclovir, valacyclovir, famcivlovir,
tx for varicella chicken pox (2)
acyclovir, valacyclovir
tx for HHV-6 (4)
cidofovir, foscarnet, ganciclovir, valganciclovir
tx for HHV-7 (1)
cidofovir
tx for HHV-8 (aka KSHV) (4)
cidofovir, famciclovir, ganciclovir, valacyclovir
tx for HHV-8 infection*??
ganciclovir, valganciclovir
used to treat herpes labialis
penciclovir–> a metabolite of famciclovir
acyclovir used to treat
varicella zoster and varicella chicken pox
cidofovir usewul against
pox viruses, HHV6, 7 and 8 (not active)
famciclovir used to treat
varicella zoster, HHV8 (not active)
foscarnet used to treat
HHV-6
gaciclovir used to treat
HHV6, HHV8, HHV8 active
valacyclovir used to treat
Varicella zoster, varicella chicken pox, HHV8 (not active)
Valganciclovir used to treat
HHV-6, HHV 8 active
describe herpes virus
linear, DNA, enveloped, icosahedral
herpes virus life cycle
attachment, entry, uncoating, localisation to the nucleus
>immediate early proteins transcribed
>DNA replication
>bulk of genes (late genes) exressed
>late proteins incorporated into forming new virion progeny
>release/lysis
name the immediate early genes
thymidine kinase
DNA polymerase
drugs that inhibit DNA polymerase after transcription of the Immediate early gene products
foscarnet, ganciclovir, acyclovir, valacylovir, valganciclovir, cidofovir
*i think its just all of them
DNA viruses translate mRNA into protein using….
host ribosomes
how does acyclovir and valacyclovir work in the nucleus
viral thymidine kinase (an immediate early gene product)–> takes it from AMP–ATP..then it is preferentially encorporated into the gorowing DNA replicating chain…the chain is then terminated
why does acyclovir cause chain termination
lacks the 3’ oh group needed for addition of new subunit
ganciclovir/ valganiclovir have what difference from vala and acyclovir
they HAVE the 3’ OH group…so further DNA synthesis is possible once encorporated
foscarnet acts via
pyrophosphate binding site of viral DNA polymerase (a immediate early product) AS WELL AS REVERSE TRANSCRIPTASE–> prevents celavage of pyrophosphate (Pi-Pi) from nucleotide triphosphate–> stalling further primer template extension
*stuck in the PPP form–> needs to be P form)
which drugs competitively inhibit viral DNA polymerase; compete with dGTP for incorporation into viral DNA
Acylovir valacyclovir ganciclovir valganciclovir famciclovir
Cidofovir MOA
competitively inhibit viral DNA polymerase; compete with dCTP for incorporation into viral DNA
KINASE DEFICIENT viral strains (not encoding a thymidine kinase) are resistant to which drugs
- drugs that require activation and triple phosphorylation to their active products
1. Acyclovir
2. Valacyclovir
3. Famciclovir
4. ganciclovir
5. Valaganiclovir
drugs that will work on kinase deficient strains
cidofovir
foscarnet
*administered in their active state, do not require phosphorylation to be active
metabolism for all of these drugs
little metab
renally eliminiated
dose adjustment needed if renal failure..if not all can cause renal failure
lest side effects and best tolerated anti-viral
famcivlovir
ADE’s for acyclovir and valacylvovir
neurotoxicity and seizures
ADE’s for cidofovir
nephrotoxicity
minitor creatinine and urinary protein
drug that requires probenacid prophyllaxis and normal saline
cidofovir
ADE’S FOR FAMCICLOVIR
NONE
ade’s for foscarnet
electrolyte imbalance
chelate Calcium ions
ADE’s for gancilclovir and valnagciclovir
anemia, leukopenia, neutropenia, pancytopenia, thrombocytopenia, teratogen
proven teratogens
ganciclovir
valganciclovir
which drugs will have cross reactive hypersensitivity
acyclovir famciclovir ganciclovir valacyclovir valganciclovir
treating HHV6 with Valganciclovir or Ganciclovir->and have a hypersensitivty reaction-> can switch to
cidofovir or foscarnet
treating HHV-8 (not active) with Fam,Gan or Val and have hypersensitivity reaction…can switch to
cidofovir– only thing effective and non-allergic
