Contraception and anti-retroviral drug interactions Flashcards
what does NRTI stand for
Nucleoside reverse transcriptase inhibitors
what is the MOA of NRTI
NRTI bind to the receptors of reverse transcriptase preventing reverse transcription from being able to take place this therefore prevents viral RNA being transcribed into DNA and thus viral replication
Tenofovir disoproxil, Tenofovir alfenamide, emtricitabine, abacavir, lamvuidine, zidovudine are examples of which class of ARTs
A - NNRTI
B- protease inhibitors
C- intergrase inhibitors
D - NRTI
D - NRTI
Zidovuidine belongs to which class of ART
A - NNRTI
B- protease inhibitors
C- intergrase inhibitors
D - NRTI
d - nrti
abacavir belongs to which class of ART
A - NNRTI
B- protease inhibitors
C- intergrase inhibitors
D - NRTI
d - nrti
effavirenz belongs to which class of ART
A - NNRTI
B- protease inhibitors
C- intergrase inhibitors
D - NRTI
A - NNRTI (non nucleoside reverse transcriptase inhibitors)
what is the mode of action of NNRTI (non nucleoside reverse transcriptase inhibitors)
NNRTI work by binding to the reverse transcriptase enzyme (but not the receptor like NRTI) this causes the receptor to change shape meaning that HIV RNA can not bind halting viral replication
Rilpvirine, nevirapine, Etravirine and Doravarine are examples of which class of ART
A - NNRTI
B- protease inhibitors
C- intergrase inhibitors
D - NRTI
A - NNRTI
Name two intergrase inhibitors
Dolutegravir, Bictegravir
Intergrase inhibitors end in ‘gravir’
what is the mode of action of intergrase inhibitors
intergrase inhibitors block the action of the enzyme intergrase which works to integrate HIV DNA into host DNA
Bictegravir, dolutegravir, elvitegravir, raltegravir and cabotegravir are all examples of which class of ART
A - NNRTI
B- protease inhibitors
C- intergrase inhibitors
D - NRTI
C - intergrase inhibitors
which class of ART block the ability of HIV to bind to CD4 T cell receptors
Entry inhibitors
can you name an example of an entry inhibitor
Maraviroc
what are the two types of entry inhibitor ART
CCR5 inhibitors
fusion inhibiors
which receptor does Maraviroc act on
CCR5
what is the mode of action of protease inhibitors
block the enzyme protease (HIV uses protease to break up large polyproteins into smaller pieces required for viral particle assembly)
Atazanavir, Darunavir, Lopinavir are all examples of which class of ART
A - NNRTI
B- protease inhibitors
C- intergrase inhibitors
D - NRTI
B - protease inhibitors
Enfuvitiride is an example of which class of ART
A - fusion inhibitor
B- protease inhibitors
C- intergrase inhibitors
D - NRTI
A - fusion inhibitor
what is the mode of action of boosted drugs used in ART
boosted drugs aim to boost the effectiveness of protease inhibitors, it makes the liver break down protease inhibitors slower which means the body is exposed to higher levels of serum ART. Without the booster drug the prescribed drug would not be effective
Ritonavir and cobicistat are examples of which class of ART
A - NNRTI
B- protease inhibitors
C- intergrase inhibitors
D - NRTI
E- boosted drugs
E- boosted drugs
what type of virus is HIV
- single stranded DNA
-single stranded RNA
-double stranded DNA
-single stranded RNA
single stranded RNA virus
what class of viruses does HIV belong to
lentivirus
name the ART that interacts with all forms of hormonal contraception excluding IUD (IUS/IUCD) and depo
Efavirenz
what is Efavirenz effect on emergency contraception
Efavirenz is an enzyme inducer potential to decrease plasma level of levonorgestrel and ulipristal acetate
ART efficacy is effected by contraception drug interactions - true or false
false - no evidence that any contraception effects the efficacy of ART. It is the reverse that ARTs can reduce the efficacy of contraception methods
which two classes of ART are considered inducers of the P450 system
ritonavir boosted protease inhibitors and NNRTIs (specifically Efavirenz)
(inducers speed up metabolism of contraception and therefore decrease its efficacy)
NRTIs are considered safe will all forms of hormonal contraception (excluding oral EC)
True or false
true
which NNRTI should we avoid using hormonal contraception (oral EC, POP/CHC, implant) with and why
Efavirenz is a enzyme inducer of P450 system and should be avoided with all forms of hormonal contraception including oral EC
what methods of contraception are considered safe with Effavirenz
IUS, IUCD, depo provera
Are etravirine and nevirapine considered enzyme inducers or inhibitors of P450 system
enzyme inducers, potential weak interaction but not expected to lower HC effectiveness. FSRH advise to consider different option but could be used if patient understands potential risk as not considered to
which two NNRTIs are considered safe with all forms of hormonal contraception
Doravirine and rilpivirine
intergrase inhibitors are considered safe with all forms of contraception
True or false
True
e.g. dolutegravir, raltegravir, bictegravir
what effect do boosted protease inhibitors have on hormonal contraception
increase in progestogen levels and EE levels remain unchanged or slightly decreased
what is the advice regarding patients using enzyme inducing ART with emergency contraception
ideally avoid oral EC and advice EC-IUD as best option
no evidence of double dosing ART
if IUCD is not an option for the patient suggest double dose levonorgestrel but not to double dose ulipristal acetate (no evidence on how effective this is)
what is the risk of of HIV acquisition from one episode of receptive vaginal sex with a partner known to be HIV positive with detectable viral load?
0.1%
what type of sex has the highest risk of HIV acquisition
receptive anal sex (1.11%)
Sally is a 32 year old female diagnosed with HIV and taking ART. Her HIV viral load is undetectable. She wants advice regarding contraception. She tells you her ART consists of efavirenz with tenofovir disoproxil. Which of the following is the most suitable form of contraception.
A- IUS
B- Implant
C- CHC
D- POP
A - IUS (Efavirenz is an enzyme inducer and therefore should be avoided with hormonal contraception except IUS/cu - IUD and depo
boosted PI with carbocistat has the following effect on hormonal contraception
A - increases estradiol and progestogen levels
B- increased estradiol and decreases progestogen levels
C- decreases estradiol and progestogen levels
D- decreases estradiol and increases progestogen levels
A - increases estradiol and progestogen levels (hence FSRH recommend considering not using CHC due to potential theoretical increase in thrombosis risk)
cobocistat is an inhibitor - inhibits metabolism of EE and P
what does contraception efficacy rely on progestogen or oestrogen?
Progestogen exposure
list the anti-retrovirals that should be avoided with hormonal EC and why
Efavirenz - enzyme inducer
Etravarine - enzyme inducer
Neviparine - enzyme inducer
Can boosted PIs be used with oral EC (e.g. ritonavir and carbocistat boosted (atanzavir, darunavir, lopinavir)
yes fine with oral EC as if anything they lead to increased serum progestogen levels so don’t decrease efficacy of oral EC
protease inhibitors are enzyme inducers or inhibitors of Cytochrome P450 enzyme
inhibitors therefore lead to increased levels of serum hormones in contraception
booster PIs are enzyme inducers or inhibitors of cytochrome P450 enzyme
inducers
carbocistat an inducer or inhibitor of P450
inhibits - leads to increased levels of estradiol and progestogen (theoretical increase risk of thrombosis)
is ritonavir an inducer or inhibitor of P450
both - it induces metabolism of EE and decreases metabolism of P therefore unlikely to affect hormonal contraceptive effectiveness, just perhaps a few more se due to low oestrogen e.g. irregular bleeding.
