Anti-retrovirals Flashcards
abacavir
NRTI
didanosine
NRTI
emtricitabine
NRTI
lamivudine
NRTI
stavudine
NRTI
tenofovir
NRTI
zidovudine
NRTI
efavirenz
NNRTI
nevirapine
NNRTI
rilpivirine
NNRTI
atazanavir
protease inhib
darunavir
protease inhib
indinavir
protease inhib
lopinavir
protease inhib
nelfinavir
protease inhib
enfuviritide
entry inhibitor
maraviroc
entry inhibitor
dolutegravir
integrase inhib
elvitegravir
integrase inhib
raltegravir
integrase inhib
cobicistat
pharmacokinetic enhancers
ritonavir
pharmacokinetic enhancer
NRTI MOA
riboside analog - lacking 3’ OH
phosphorylated by cell enzymes, incorp into viral DNA = terminates DNA elongation
COMPETITIVE INHIB of RT
active against HIV-1 and 2
(1 - western world. 2 - west africa)
NRTI resistance
rapidly emerges if used alone
most common mutation at viral codon 184 - lamivudine; can inc sensitivity to zidovudine and tenofovoir
cross resistance does occur
dose changes with renal insufficiency
NRTI AE
inhib mitochondrial DNA pol = periph neuropathy, myopathy, lipoatrophy, lactic acidosis
pancreatitis
myelosuppression
fatal liver toxicity - rare
zidovudine and stavudine = dyslipidemia, insulin resistance
NRTI interactions
didanosine and tenofovir: tenofovir inc didanosine levels (must reduce didanosine levels)
not metabolized by cytochrome enzymes
zidovudine
thymidine analog
(ZDV, AZT)
oral
crosses BBB
dosage adj in cirrhosis
zidovudine AE
BM suppression
ganciclovir + zidovudine
BOTH CAUSE BM SUPPRESSION - don’t give together
zidovudine contraindications
coadmin with acetaminophen, lorazepam, indomethacin, cimetidine
Stavudine
(d4T)
inhibitor of beta and gamma DNA polymerases (high aff for mitochondrial DNA pol)
thymidine analog
oral
stavudine AE
peripheral neuropathy
lactic acidosis
hyperlipidemia
NM weakness
Didanosine
adenosine analog
best if taken in fasting state - acid labile
penetrates CSF
Didanosine AE
PANCREATITIS
peripheral neuropathy, diarrhea, hepatic dysfunction, CNS effects
Tenofovoir
(TDF)
adenosine nucleotide analog
combos: tenofovir + emtricitabine AND tenofovir + emtricitabine + efavirenz
tenofovir PK
take with food to inc bioavail
long t 1/2
only NRTI with significant drug interaction
tenofovir + didanosine
Tenofovir decreases concentrations of atazanavir
Can boost atazanavir with ritonavir
Lamivudine
(3TC)
no affect on mitochondrial DNA or BM
cytosine nucleoside analog
emtricitabine
relative of lamivudine
cytosine nucleoside analg
emtricitabine AE
hyperpigmentation - more frequently in darker skinned
abacavir
guanosine nucleoside analog
abacavir AE
GI, HA
5% hypersensitivity reaction - rash, GI, malaise, respiratory distress
CONTRAINDIC in HLA-B 5701 mutation
don’t ever rechallenge sensitized individuals
NNRTI MOA
selectively, noncomp inhibitor of HIV-1 RT
don’t bind at active site
inhibit RNA and DNA dep DNA pol
NO phosphorylation by cellular enzymes
no activity against HIV-2
NNRTI adv/disadv
no cross resistance, effect on host blood forming elements
cross ressistance within NNRTI’s. drug interactions. high incidence of hypersensitivty
NNRTI’s AE
skin rash – stevens johnson syndrome
CYP3A4 substrates: can act as inducers, inhibitors, or both of CYP
Nevirapine excretion
urine - CYP3A4, 2B6
nevirapine AE
hepatotoxicity (severe)
- don’t use unless have to
rash
titration period for 14 days at 1/2 dose to dec risk of serious epidermal reactions
nevirapine PK
CYP3A4 inducer
increases metab of PI’s , OCP, ketoconazole, methoadone, metronidazole, quinidne, theophylline, warfarin
efavirenz
increases CD4+ counts, dec viral load
oral
40 hr half life
P450 inducer
efavirenz AE
high rate of CNS toxicity
rash
inc TG, HDL, cholest (must monitor lipids)
contraindcated in pregnancy - but can be used after 1st trimerster
Rilpivirine AE
**Rash
insomina, depression
LFTs increased
Protease inhibitor MOA
reversible inhib of HIV aspartyl protease = prevents viral maturation and production of non-infectious virions
NO intracellualr activ required
active against HIV-1 and 2
Protease inhib PK
poor oral bioavail -
high fat inc = nelfinavir
high fat dec = indinavir
substrate for CYP3A4
substrate for P glycoprotein pump
bound to plasma proteins = dec amt of free drug available to pt (alpha1-acid glycoprotein)
protease inhib AE
parathesias, n/v/d
disturbances in lipid metab
fat redistribution and accum: central obesity, dorsocervical fat enlargement - buffalo hump, peripheral wasting; cushingoid appearance –> AE decreases compliance
protease inhib contraindic
CYP inhibitors
- rhabdo (simvastain), excess sedation (midzolam), respiratory depression (fentanyl)
warfarin, sildenafil, phenytoin - require dosage adj
contraindic with rifampin and st john’s wort
PI resistance
stepwise mutations of protease gene
atazanavir AE
PR interval prolongation
benign hyperbilirubinemia
rash
nephrolithiasis
Which protease inhib is NOT given with RTV
Nelfinavir
b/c metabolized by several CYPs
Enfuviritide
(T-20)
inhibits viral fusion
“Tx-experienced pt with evidence of HIV replication”
No activity against HIV-2
enfuviratide MOA
gp41 structural analog
binds gp41 - prevent ability of virion to fuse to cell membrane
enfuvirataide contraindications
NO drug interactions with other retrovirals
Maraviroc MOA
binds only CCR5 - blocking HIV entry
maraviroc PK
CYP3A4 metabolized
Integrase strand transfer inhibitor
approved for tx experienced and tx naive
INSTI MOA
binds integrase
inhibits final step of integration of viral DNA into host cell DNA
INSTI’s AE
rash, nausea, diarrhea, insomnia, HA
inc in creatine phosphokinases, myopathy, rhabdo, hypersensitivity
Dolutegravir
eliminated via glucronidation via UGT1A1
Elvitegravir
CYP3A4 metabolized - may require enhancer (Cobicistat)
Raltegravir
eliminiated by glucoronidation by UGT1A1
raltegravir AE
can cause increases in creatine phosphokinases
raltegravir interactions
rifampin
tipranavir
efavirenz
= may dec raltegravir
PPI can increase raltegravir
ritonavir
PK enhancer
cobicistat
PK enhancer
PK enhancer MOA
CYP3A4 inhibitor
Inc plasma concen of ARV = allows for lower and/or less frequent dosing
improves tolerability of ARV
Ritonavir use
in combo with PI’s (not nelfinavir)
NEVER USED ALONE
what drug is ritonavir never used with?
nelfinavir
cobicistat use
combo with INSTI - elvitegravir, also with darunavir and atazanavir
Initial Tx for Treatment-naive pt
2x NRTI + INSTI
OR
2x NRTI + PI
avoid use of 2 agents of same nucleotide analog, overlapping toxicity
INSTI based regiments
1) Raltegravir + tenofovir + emtricitabine
2) Dolutegravir + tenofovir + emtricitabine
PI based regiment
Ritonavir boosted with darunavir + tenofovir + emtricitabine
HIV prophylaxis following needle stick
raltegravir + tenofovir + emtricitabine (x28 days)
HIV prophylactic vaccines
S. pneumo
HAV
HBV
Influenza
Vaccines contraindic in HIV pt with CD4 <200
LIVE VACCINES:
MMR
Varicella
Zoster
darunavir
inhibits CYP3A4
avoid in pt with sulfur allergy
indinavir
give with RTV
absorption dec with meals
nephrolithiasis
hyperbili
blurred vision
lopinavir
give with RTV
contraindic with inducers (St. Johns wort)
Avoid with disulfiram or metronidazole - contains EtOH
nelfinavir
lots of contraindications b/c CYP inhibition