Post exposure prophylaxis Flashcards
What is the usual regime of PEP for HIV
TDF/FTC (tenofovir disoproxil 245mg/emtricitabine 200mg) OD+ raltegravir 1200mg OD for 28 days
i.e. contains three different anti-retrovirals in two tablets, take one of each tablet OD (so two tablets OD)
if prescribing PEP for HIV to a patient that is pregnant what is the recommended regime?
TDF/FTC + raltegravir 400mg BD for 28 days
If there is a pregnancy risk or the patient is in the first 6 weeks of pregnancy and can’t take raltegravir which third agent ART should be avoided?
Dolutegravir
how long is a course of PEP
28 days
what are the missed pill rules for PEP
if you have missed a dose take it as soon as you remember,
if you are due your next dose of PEP don’t double dose
if it has been >48 hours since your last dose of PEP discontinue the PEP and contact the sexual health service
what should you council women who are pregnant or breastfeeding regarding use of PEP
PEP in pregnant and BF women is unlicensed. However we use ART in these conditions for women who are HIV positive and so we are confident it is safe and not harmful to a developing baby.
ART can transfer into breast milk so baby will be exposed, no studies. would probably recommend avoiding breastfeeding due to risk of seroconversion though.
decision to prescribe PEP shouldn’t change because a patient is pregnant or breastfeeding
when might someone need PEP when taking PrEP but missed doses any having anal sex only?
Pt taking PrEP for anal sex and there has been a sexual risk (unprotected receptive or insertive anal if HIV positive and unknown VL or if receptive anal sex and high risk group and HIV status unknown, if insertive anal sex and high risk group would be a CONSIDER category):-
1. if taking PrEP daily dosing and less than 4 doses in the last 7 days = PEP
2. if taking EBD = if not followed EBD rules correctly (i.e. double dose on day of sex at least 2 hours-24 hours prior to sex and then one dose daily/every 24 hours to be continued for a minimum of 48 hours after the last sexual exposure)
what is the recommended time frame for PEP to be started following a potential HIV exposure?
PEP needs to be started within 72 hours following an exposure but ideally less than 24 hours
how long is a course of PEP?
28 days
if there has been further HIV risk whilst on PEP what would you advise the patient in terms of PEP course?
if anal risk within last 2 days of finishing PEP course continue for further 48 hours
- if vaginal sex risk within last 2 days of finishing PEP continue for further 7 days
when might someone require PEP if taking PrEP when having vaginal sex or frontal/ neovaginal sex?
If more than 48 hours since last PrEP dose or fewer than 6 doses in the last 7 days and sexual risk has occurred
what would you advise a patient when taking PEP to look out for and why?
risk of seroconversion - flu like symptoms or a rash, seroconversion can be asymptomatic as well. In these situations patients should continue their PEP and until they get advice from HIV/Sexual health specialist.
what are the side effects associated with PEP
PEP is generally very well tolerated, commonest SE are headaches, nausea and diarhoea
these SE usually settle once established on PEP, tips - take at night, can use anti-emetics if needed but don’t routinely use straight away
Are there any risks with taking PEP
very safe, TDF (tenofovir) can cause proximal tubular damage but if normal Creatine (eGFR) at time of starting unlikely. We expect this to recover. In patients who eGFR <50 consider TAF - tenofovir alafenamide instead.
can get a transient rise in ALT but this usually recovers on stopping PEP
what is the study that demonstrates U=U
PARTNER study - found that U=U
undetectable = untransmissable
partner 1 included heterosexual and gay serodifferent couples, partner 2 study recruited MSM couples
was a european study
do we have good RCT evidence to base the efficacy of PEP?
no - most of our studies for PEP come from animal studies and observational studies. These demonstrate that PEP is very effective.
We have occupational studies that suggest it is very effective and we extrapolate this data
what are the baseline tests required before starting PEP in sexual exposure has occurred
bloods - U&E and LFTs (not needed to be repeated if normal)
UPT in any patient of childbearing potential
STI screen - HIV, STS, hepatitis B/C and
GC and CT from appropriate sites dependent upon sexual risk
starting PEP should not be delayed to wait for results to come back
why is it important to check hep B status and if not immune offer hep B vaccine
worry is that tenofovir is the treatment for hep B so theoretical risk that if you have hep B and stop the PEP or PrEP that you can cause hepatic flare can give fulimanent hep b resurfaces
when should hep B vaccine be offered?
if HepBsab <10 then offer vaccine
- super accelerated 0,7,21 days and 12 months
what type of HIV blood test do we use in testing settings
fourth line antigen-antibody HIV test (HIV-1Ag/antibody)
when should HIV blood test be repeated when you have initiated PEP
45 days after completion of PEP.
how can you calculate risk of HIV transmission?
Risk of HIV transmission = risk that source if HIV positive with a detectable viral load * risk per exposure
old PEP guidelines (2015) used to quantify risk of HIV transmission e.g. 1/1000 or 1 in 10,000.. using this way to define HIV transmission risk when would PEP be recommended/
PEP recommended if risk > 1 in 1000
( if risk of transmission between 1 in 1000 and <1/10, 000 = consider, if risk <1/10,000 not recommended)
how does the new PEP guideline categorise risk and when to give PEP
recommended, consider, generally not recommended and not recommended
what is the risk of HIV transmission in unprotected receptive anal sex with a partner known to be HIV positive with detachable VL
1 in 90 (receptive anal sex has highest HIV transmission risk)
what is the risk of HIV transmission in unprotected receptive vaginal sex with a partner known to be HIV positive with detachable VL
1 in 1000
if a partner is HIV positive with an undetectable VL what other criteria must be met to reassure a patient that they don’t need PEP
to be classed as U=U
undetectable VL and on ART for at least 6 months, with a HIV VL in last 6 months which demonstrates undetectable
undetectable VL < 200copies/ml
If the index partner is HIV positive with detectable VL or unknown VL status what is the recommendation for PEP if
a) receptive anal sex
recommend
If the index partner is HIV positive with detectable VL or unknown VL status what is the recommendation for PEP if
a) insertive anal sex
recommend
If the index partner is HIV positive with detectable VL or unknown VL status what is the recommendation for PEP if
a) receptive vaginal sex
recommend
If the index partner is HIV positive with detectable VL or unknown VL status what is the recommendation for PEP if
a) insertive vaginal sex
consider
extra considerations points which increase risk of transmission
- more details of HIV viraemia of where index patient is from
If the index partner is HIV positive with detectable VL or unknown VL status what is the recommendation for PEP if
a) oral sex with or without ejaculation (male/female)
Not recommended
If the index partner is HIV positive with detectable VL or unknown VL status what is the recommendation for PEP if
a) splash semen into the eye
Not recommended
if the index partner is HIV positive, undetectable VL, good ART adherence and bloods show undetectable VL in the last 6 months do you give PEP for risk of HIV transmission e..g needle sharing, sexual exposure, occupational exposure?
no - not recommended
If the index partner HIV status is unknown but they are from a high risk group e..g MSM or high prevalence country
a) receptive anal sex
recommend
If the index partner HIV status is unknown but they are from a high risk group e..g MSM or high prevalence country
a) insertive anal sex
consider
If the index partner HIV status is unknown but they are from a high risk group e..g MSM or high prevalence country
a) receptive vaginal sex
generally not recommended
If the index partner HIV status is unknown but they are from a high risk group e..g MSM or high prevalence country
a) insertive vaginal sex
generally not recommended
if the index partner HIV status is unknown but from a low prevalence country or group do you recommend PEP following sexual/ needle or occupational exposure
no - not recommended
try and complete the PEP risk exposure table
see table
what are the ‘c/d’ categories when HIV status is unknown but from high risk group or high prevalence area that would increase the risk of HIV transmission and therefore your decision to prescribe PEP?
- breaks in mucosal membranes e.g. GUD, trauma including sexual assault
- positive STI in either patient or index partner
- high risk group e.g. transgender
- multiple episodes of exposure in short time e.g. group sex
what are the important drug -drug interactions to remember when taking PEP
avoid cations when taking raltegravir and antacids containing cations this includes multivitamins (containing folic acid, vitamin d), iron, magnesium, aluminium
antacids containing cations = rennies, gaviscon (PPIs are fine)
why ? because they form a barrier in the GIT and reduce absorption of the raltegravir therefore reduces efficacy as decreased serum concentrations
n.b specialists say they are fine if you stagger doses like 2 hours before or after PEP
note folic acid/ vitamin don its own does not interact only if in a multi vitamin
