STIs (HIV/AIDS) Flashcards

1
Q

What type of virus is HIV?

A

Belongs to the lentivirus group, RNA virus
HIV attacks and destroys CD4 T cells

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2
Q

What are the possible mode of transmission of HIV?

A
  1. Unprotected sexual intercourse
  2. Sharing infected syringes and needles
  3. Mother to child transmission during pregnancy, at birth, and breastfeeding
  4. Transfusion with contaminated blood and blood products

*Note that HIV is transmitted through body fluids (blood, semen, genital fluids, breastmilk)

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3
Q

Who should be tested for HIV?

A
  • IV drug user
  • Unprotected sex with multiple partners
  • MSM
  • CSW
  • Persons treated for STDs
  • Recipients of multiple blood transfusion
  • Sexually assaulted
  • Pregnant women (mandatory)
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4
Q

What tests can be done to diagnose HIV infection?

A
  1. Serum antibody detection
  • HIV enzyme immunoassay antibody tests (HIV EIA tests)
  • Western Blot
  1. HIV RNA detection/quantification (viral load)
  • Nucleic acid amplification (PCR)
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5
Q

What are the 4 different stages of HIV?

A

A) Acute (primary) HIV infection

B) Asymptomatic stage

C) Persistent generalized lymphadenopathy

D) AIDS & related conditions

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6
Q

Describe the acute (primary) stage of HIV infection

A
  • Occurs soon after contracting HIV
  • Flu-like illness with swollen lymph nodes, fever, malaise, rash
  • Lasts 2-3 weeks
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7
Q

Describe the asymptomatic stage of HIV infection

A
  • No S&S
  • This stage can persist for many years
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8
Q

Describe the persistent generalized lymphadenopathy stage of HIV infection

A
  • Persistent unexplained lymph node enlargement in neck, underarms, groin
  • For more than 3 months
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9
Q

Describe AIDS and its related conditions

  • What defines/constitutes AIDS
A

AIDS = CD4 <200/mm^3 OR Presence of AIDS-defining disease

AIDS defining diseases:

  • Opportunistic infections: TB, recurrent bacterial pneumonia (pneumocystis - fungal), candidiasis, cytomegalovirus (CMV) [*CMV can cause blindness]
  • Rare cancers: Non-Hodgkins lymphoma, Kaposi sarcoma
  • AIDS dementia complex
  • Wasting syndrome, unexplained weight loss

Systemic symptoms of AIDS include: fever, unexplained wieght loss, persistent diarrhea, extremem fatigue, swollen glands in the neck, armpits, groin

May have multiple organ involvement: lung, eyes, GIT, CNS, skin etc.

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10
Q

What are the primary goals of anti-retroviral therapy?

A
  • Reduce HIV-associated morbidity and mortality (by maintaining CD4 cell count and reducing development of other AIDS associated diseases)
  • Prolong the duration and quality of survival
  • Restore and preserve immunologic function
  • Maximally and durably suppress plasma HIV viral load (to undetectable amounts, hence preventing transmission)
  • Prevent HIV transmission
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11
Q

Describe the uses of CD4 as a surrogate marker in HIV

A

CD4 cell count (normal: 500-1200, AIDS: <200)

  • Indicator of immune function
  • Strongest predictor of subsequent disease progression and survival
  • Determines urgency for initiating ART
  • Assess response to ART therapy
  • Assess need for initiating or discontinuing prophylaxis for opportunistic infections (e.g., prophylaxis for pneumocystis pneumonia is started when CD4 <200)
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12
Q

Using CD4 cell count as surrogate marker,

What are the time intervals to assess response to ART therapy?

What defines an adequate CD4 response?

A

Assess at baseline, and every 3-6 months after treatment initiation, followed by every 12 months after adequate response

Adequate response: increase in CD4 count in the range of 50-150 cells/mm3 during the first year of therapy

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13
Q

Describe the uses of viral load as a surrogate marker in HIV

A

Using HIV RNA to determine viral load

  • Most important indicator of response to ART (better than CD4)
  • Useful in predicting clinical progression (CD4 better)
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14
Q

When is viral load measured?

Also state when viral suppression is typically achieved

How long does an effective regimen generally take to achieve viral suppression?

A

Before initiation of therapy at baseline and within 2-4 weeks (not later than 8 weeks) after treatment initiation of modification, followed by every 4-8 weeks until viral load suppressed

In patients on stable regimen and suppressed viral load, monitoring can be done every 3-6 months

Effective regimen generally achieve viral suppression by 8-24 weeks

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15
Q

Who is ART recommended for?

A

All HIV-infected individuals, regardless of CD4 cell count

  • reduce morbidity and mortality a/w HIV, maintain CD4 cell count, reduce viral load, prevent transmission
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16
Q

When should ART be started?

A

Should start after educating pt on benefit + considerations + strategies to optimize adherence

  • 95% adherence required, or else 1. risk of resistance to ART agents 2. risk of treatment failure

DO NOT start (consider deferring) if pt unable to be adherent (e.g., clinical and/or psychosocial factors)

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17
Q

What are the benefits of earlier ART treatment?

A
  • Maintain higher CD4 count, prevent irreversible damage to immune system
  • Decrease risk for HIV-associated complications (when CD4 >350, may develop complications such as TB, cancer, peripheral neuropathy, cognitive impairment)
  • Decrease risk of non-opportunistic conditions (CVD, renal disease, liver disease, non-AIDs associated malignancies and infections)
  • Decreased risk of HIV transmission through viral load suppression
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18
Q

What are the limitations of earlier ART treatment?

A
  • Treatment-related side effects and toxicities
  • Development of drug resistance, loss of future treatment option due to incomplete viral suppression (if non-adherent)
  • Transmission of drug-resistant virus
  • Less time to educate patient, risk of non-adherence
  • Treatment fatigue due to greater total time on medication
  • Increased cost
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19
Q

What are the factors to consider when selecting initial regimen?

A
  • Patient’s understanding of HIV (education)
  • Cost, availability
  • Adherence issues (pill burden, dosing frequency, food and fluid considerations)
  • Virologic efficacy (higher viral load need more efficacious agent)
  • Potential adverse effects
  • Childbearing potential (avoid teratogenic agents)
  • Genotypic drug resistance testing (test for genes a/w resistance to certain drugs - drug resistant virus)
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20
Q

Briefly describe the life cycle of HIV

A
  1. Free virus
  2. Binding and fusion
  • bind to CD4 receptor + CCR5 or CXCR4 co-receptors
  • fusion of virus and host cells’ cell membrane
  1. VIrus penetrates cell and releases 2 viral HIV RNA strand + 3 replication enzymes (reverse transcriptase, integrase, protease)
  2. Reverse transcription (single strand RNA => double stranded DNA)
  3. Integration (viral DNA combined with host cell’s DNA)
  4. Transcription (RNA => protein)
  5. Assembly
  6. Budding
  7. Immature virus breaks free from infected cell
  8. Maturation (protease cleaves protein chain, makes a working virus)
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21
Q

ART armamentarium:

A

CCR5 antagonist
Fusion/entry inhibitor
Reverse transcriptase inhibitor
Integrase strand transfer inhibitor
Protease inhibitor

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22
Q

What are the recommended combinations for patients naive to ART?

A

2 NRTIs + 1 INSTI

  • Tenofovir + Emtricitabine + Bictegravir (TEB)
  • Tenofovir + Emtricitabine + Dolutegravir (TED)
  • Abacavir + Lamivudine + Dolutegravir (LAD)

1 NRTI + 1 INSTI

  • Emtricitabine + Dolutegravir (ED)

Other combi: NNRTI + NRTI

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23
Q

1 NRTI + 1 INSTI is not recommended for which group of patient and why?

A

Emtricitabine (NRTI) + Dolutegravir (INSTI)

  • Not recommended for patients with HIV RNA >500,000 (very high viral load, use 2 NRTIs + 1 INSTI instead)
  • Not recommended for patients with Hep B coinfection (Hep B tx require at least 2 NRTI: either Tenofovir, Emtricitabine, or Lamivudine) => incr risk of mutation and resistance of HBV
  • Not recommended for patients in whom ART is to be started before the results of 1. HIV genotypic resistance testing or 2. HBV testing are available
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24
Q

List the Nucleoside Reverse Transcriptase Inhibitors (NRTIs)

A
  • Tenofovir
  • Emtricitabine
  • Abacavir
  • Lamivudine
  • Zidovudine
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25
Q

What are the class advantages of NRTIs?

A
  • Established dual backbone of combi ART
  • Renal elimination, little concerns of CYP DDIs
26
Q

What are the class disadvantages of NRTIs?

A
  1. Adverse effects related to mitochondrial toxicity
  • Lactic acidosis and hepatic steatosis (fatty infiltrate)
  • Lipoatrophy (lost of fat)
  • More a/w Zidovudine (older drug)
  1. Require renal dose adjustment
27
Q

Which NRTI does not require renal dose adjustment?

A

Abacavir

28
Q

What are the specific adverse effects a/w Lamivudine?

A
  • Minimal toxicity
  • Nausea, vomiting, diarrhea
29
Q

What are the specific adverse effects a/w Emtricitabine?

A
  • Minimal toxicity
  • Nausea, diarrhea
  • Hyperpigmentation

HE

30
Q

What are the specific adverse effects a/w Tenofovir?

A
  • Nausea, vomiting, diarrhea
  • Renal impairment
  • Decrease in bone mineral density (incr risk of osteoporosis, osteopenia)
31
Q

Explain the differences in the incidence of adverse effect between the two Tenofovir formulations

A

Tenofovir Alafenamide (TAF) vs Tenofovir Disoproxil Fumarate (TDF)

  • TDF is more a/w with higher incidence or renal impairment + dcr in BMD
  • FYI: TAF targets liver cells (more specific in Hep B)
32
Q

What are the specific adverse effects a/w Abacavir?

A
  • Nausea, vomiting, diarrhea
  • Hypersensitivity rxn in pt with HLA-B*5701

=> Symptoms: rash, fever, malaise, LOA, sore throat, cough, SOB
=> Fatal, if occur, discontinue and do not rechallenge
=> Test for HLA-B*5701 allele

  • Concern for myocardial infarction

=> do not use in high CVD risk patients

HMA

33
Q

What are the specific adverse effects a/w Zidovudine?

A
  • Nausea, vomiting, diarrhea
  • Myopathy
  • Bone marrow suppression - may cause anemia, neutropenia (monitor FBC)

BMZ

34
Q

List the Integrase Strand Transfer Inhibitors (INSTI)

A

-gravir

Raltegravir
Elvitegravir
Dolutegravir
Bictegravir

(oldest to newest)

35
Q

What are the class advantages of INSTIs?

A
  • B & D have good virologic effectiveness
  • High genetic barrier to resistance (B/D > R/E)
  • Generally well-tolerated
36
Q

What are the class disadvantages of INSTIs?

A

ADR:

  • Nausea, diarrhea, headache, weight gain
  • Depression and suicidality (rare, primarily in pt with preexisting psychiatric conditions)

DDI:

  • Lower bioavailability when administered with polyvalent cations
  • B, D, E are CYP3A4 substrates

INSTIGATE DEPRESSION and SUICIDE, DO NOT MIX

37
Q

What is a specific adverse effect of Bictegravir and Dolutegravir?

A

They incr serum creatinine by inhibiting the tubular secretion of creatinine (but do not impact glomerular function, do not cause kidney impairment)

38
Q

What is a specific adverse effect of Raltegravir?

A
  • Pyrexia (fever)
  • Creatine kinase elevation (rhabdomyolysis - dark urine)

PCR

39
Q

Which INSTI may require PK enhancer to increase its concentration?

A

Elvitegravir

(PK enhancers: Ritonavir, Cobicistat)

40
Q

List the Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs)

A

Efavirenz
Rilpivirine

ER

41
Q

What are the class advantages of NNRTIs?

A
  • Long half-life (once daily dosing)
  • Less metabolic toxicity (less hyperlipidemia, insulin resistance compared to PI)
42
Q

What are the class disadvantages of NNRTIs?

A
  • Low genetic barrier to resistance
  • Cross resistance among approved NNRTIs
  • Skin rash, SJS (Efavirenz > Rilpivirine)
  • CYP450 DDI
  • QTc prolongation

LCSCQ

43
Q

What are the specific adverse effects of Efavirenz?

A
  • Rash (more than rilpivirine)
  • Hyperlipidemia (incr LDL-C, TG)
  • Neuropsychiatric SE (dizziness, depression, insomnia, abnormal dreams, hallucination)
  • Hepatotoxicity

HHRN

44
Q

What are the specific adverse effects of Rilpivirine?

A
  • Depression, headache

*NNRTI of choice due to less SEs

45
Q

Efavirenz and Rilpivirine are ______ substrates

Efavirenz is also an inducer of ___________

A

Efavirenz and Rilpivirine are CYP3A4 substrates

Efavirenz is a CYP2B6 and CYP2C19 inducer

46
Q

Comment on Rilpivirine administration

A

Oral absorption is reduced with increased gastric pH
Use with PPI is contraindicated

47
Q

List the Protease Inhibitors (PIs)

A
  • navir

Atazanavir
Darunavir
Ritonavir
Fosamprenavir
Lopinavir

ADRFL (ADR From PIL)

48
Q

Protease inhibitors are co-formulated with?

A

PK enhancers (Ritonavir or Cobicistat)
=> they are CYP450 3A4 inhibitors, included in the formation to increase the concentration of the antiviral

*Also co-formulated with INSTI - Elvitegravir - CYP3A4 substrate)

49
Q

What are the class advantages of PI?

A
  • High genetic barrier to resistance
  • PI resistance less common
50
Q

What are the class disadvantages of PI?

A
  • Metabolic complications (dyslipidemia, insulin resistance)
  • GI SEs (nausea, vomiting, diarrhea)
  • Hepatotoxicity (esp with chronic Hep B or C)
  • CYP3A4 inhibitors and substrates - DDI potential
  • Morphologic complications: fat maldistribution (lipohypertrophy)
  • Increased risk of osteopenia, osteoporosis (loss of BMD)

PI
HCLGMO

51
Q

What are the specific adverse effects of Ritonavir?

A
  • Potent CYP3A4, 2D6 inhibitor (PK enhancer)
  • Paresthesia (numbness of extremities)
  • Taste perversion

RP TP

52
Q

What are the specific adverse effects of Darunavir?

A
  • Good GI tolerability
  • Less lipids effects
  • Skin rash, concern for SJS

*It is a sulphonamide

53
Q

What are the specific adverse effects of Atazanavir?

A
  • Good GI tolerability
  • Less lipid effects
  • Hyperbilirubinemia
  • Prolong QT interval
  • Skin rash

Happy Birthday to SQ Agent

Administration:
- Absorption depends on low pH (CI with concurrent PPI use)

54
Q

Name a fusion inhibitor

A

Enfuvirtide

55
Q

How is Enfuvirtide administered?

A

Subcutaneous injection 2x/day

56
Q

What are the advantages of Enfuvirtide?

A
  • no appreciable drug interactions
57
Q

What are the disadvantages of Enfuvirtide?

A
  • injection site reaction (erythema, induration, nodules/cyst, pruritis, ecchymosis)
  • rare hypersensitivity (fever, rash, chills, decrease BP)
  • increased bacterial pneumonia

IRB

58
Q

Name a CCR5 antagonist

A

Maraviroc

59
Q

Explain which group of patient can use Maraviroc

A

Only in people whose strain of HIV uses CCR5 receptor to enter the CD4 cells

  • Assess using co-receptor tropism assay before initiation
  • Must be CCR5 predominant (do not use if CXCR4 or dual/mixed tropism)
60
Q

What are the adverse drug reactions a/w Maraviroc?

A
  • Abdominal pain
  • Cough
  • Dizziness
  • Musculoskeletal symptoms
  • Pyrexia
  • Rash
  • URTIs
  • Hepatotoxicity (rare)
  • Orthostatic hypotension (rare)

DDI: CYP3A4 substrate

MARVEL OH has Abs, Muscles, but URTIs and Rash