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Questions and Answers
Why is rifampin generally avoided in tuberculosis (TB) patients who are also taking protease inhibitors (PIs) for HIV?
Why is rifampin generally avoided in tuberculosis (TB) patients who are also taking protease inhibitors (PIs) for HIV?
- Rifampin directly counteracts the antiviral effects of protease inhibitors, rendering HIV treatment ineffective.
- Rifampin and protease inhibitors compete for the same metabolic pathways, leading to increased toxicity.
- Rifampin exacerbates the side effects of protease inhibitors, such as hyperlipidemia and insulin resistance, making the combined treatment intolerable.
- Rifampin induces cytochrome P450 enzymes, which can significantly lower protease inhibitor blood levels, potentially leading to treatment failure. (correct)
A patient on a stable antiretroviral regimen including tenofovir disoproxil fumarate (TDF) for HIV also tests positive for Hepatitis B virus (HBV). If the decision is made to switch the patient to a different NRTI-based regimen without HBV activity, what is the most critical next step?
A patient on a stable antiretroviral regimen including tenofovir disoproxil fumarate (TDF) for HIV also tests positive for Hepatitis B virus (HBV). If the decision is made to switch the patient to a different NRTI-based regimen without HBV activity, what is the most critical next step?
- Ensure the patient receives adequate HBV treatment concurrently to avoid HBV exacerbation upon TDF cessation. (correct)
- Immediately discontinue the TDF-containing regimen and start the new NRTI to minimize potential drug interactions.
- Administer a full course of HBV vaccination before discontinuing TDF to prevent any reactivation of the virus.
- Monitor the patient's liver function tests more frequently and adjust the dose of the new NRTI accordingly.
A patient presents with a history of depression and is newly diagnosed with HIV. Considering the side effect profiles of different antiretroviral classes, which of the following regimens should be approached with the most caution due to potential exacerbation of psychiatric symptoms?
A patient presents with a history of depression and is newly diagnosed with HIV. Considering the side effect profiles of different antiretroviral classes, which of the following regimens should be approached with the most caution due to potential exacerbation of psychiatric symptoms?
- A regimen based on non-nucleoside reverse transcriptase inhibitors (NNRTIs), particularly efavirenz. (correct)
- A regimen based on fusion inhibitors.
- A regimen based on nucleoside reverse transcriptase inhibitors (NRTIs).
- A regimen based on protease inhibitors (PIs).
A patient is prescribed maraviroc (Selzentry) as part of their HIV treatment regimen. What specific testing must be performed prior to initiating therapy, and why is it essential?
A patient is prescribed maraviroc (Selzentry) as part of their HIV treatment regimen. What specific testing must be performed prior to initiating therapy, and why is it essential?
A patient on an antiretroviral regimen reports persistent nausea, vomiting, and fatigue. Lab results reveal elevated lactate levels and hepatomegaly with steatosis. Which class of antiretroviral drugs is most likely contributing to these symptoms?
A patient on an antiretroviral regimen reports persistent nausea, vomiting, and fatigue. Lab results reveal elevated lactate levels and hepatomegaly with steatosis. Which class of antiretroviral drugs is most likely contributing to these symptoms?
A patient with HIV is starting an integrase strand transfer inhibitor (INSTI)-based regimen. They regularly use antacids for heartburn. What specific counseling point is most important to provide regarding the interaction between INSTIs and antacids?
A patient with HIV is starting an integrase strand transfer inhibitor (INSTI)-based regimen. They regularly use antacids for heartburn. What specific counseling point is most important to provide regarding the interaction between INSTIs and antacids?
In the context of HIV treatment, what is the primary mechanism by which cobicistat enhances the effectiveness of certain antiretroviral drugs?
In the context of HIV treatment, what is the primary mechanism by which cobicistat enhances the effectiveness of certain antiretroviral drugs?
What is the significance of monitoring HIV viral load and CD4 count in patients undergoing antiretroviral therapy, and how does their dynamic relationship inform treatment decisions?
What is the significance of monitoring HIV viral load and CD4 count in patients undergoing antiretroviral therapy, and how does their dynamic relationship inform treatment decisions?
A patient receiving enfuvirtide (Fuzeon) as part of their HIV treatment regimen reports experiencing significant pain, redness, and nodules at the injection sites. What is the most appropriate course of action to manage these adverse effects?
A patient receiving enfuvirtide (Fuzeon) as part of their HIV treatment regimen reports experiencing significant pain, redness, and nodules at the injection sites. What is the most appropriate course of action to manage these adverse effects?
Which of the following statements accurately describes the role and clinical application of ibalizumab-uiyk (Trogarzo) in HIV treatment?
Which of the following statements accurately describes the role and clinical application of ibalizumab-uiyk (Trogarzo) in HIV treatment?
Flashcards
First-line HIV Treatment
First-line HIV Treatment
Combined therapy using INSTI + 2 NRTIs. Examples include Biktarvy, Dovato, and Triumeq.
Integrase Inhibitors (INSTIs)
Integrase Inhibitors (INSTIs)
Inhibit HIV integrase, preventing viral DNA insertion into host cell DNA.
Examples of INSTIs
Examples of INSTIs
Raltegravir, elvitegravir, dolutegravir, bictegravir.
NRTIs
NRTIs
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Examples of NRTIs
Examples of NRTIs
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Abacavir precaution
Abacavir precaution
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NNRTIs
NNRTIs
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Examples of NNRTIs
Examples of NNRTIs
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Fusion Inhibitors
Fusion Inhibitors
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Maraviroc
Maraviroc
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Study Notes
- HIV medication mechanisms involve viral glycoprotein binding to host cell CD4 and chemokine receptors, leading to membrane fusion via gp41 and virion entry.
- After uncoating, reverse transcription converts HIV RNA to double-stranded DNA, which integrates into the host genome.
- Host cell enzymes produce mRNA, translated into proteins that form immature virions, which bud from the cell membrane.
- Proteolytic cleavage results in maturation into fully infectious virions.
- Treatment includes an integrase strand transfer inhibitor (INSTI) combined with two nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs).
- Examples of INSTIs include dolutegravir or bictegravir.
- Examples of NRTIs include tenofovir disoproxil fumarate (or tenofovir alafenamide with emtricitabine or lamivudine.
- Alternative treatments include a protease inhibitor with two NRTIs, or non-nucleoside reverse transcriptase inhibitors plus two NRTIs.
- Combination drugs like Biktarvy, Dovato, and Triumeq are used as first-line treatments for naive HIV patients.
Integrase Inhibitors (INSTIs)
- INSTIs inhibit HIV integrase, preventing viral DNA insertion into host cell DNA.
- Preferred treatment: 1 INSTI + 2 NRTIs for most naive HIV-positive adults.
- Examples of INSTIs: raltegravir, elvitegravir, dolutegravir, bictegravir.
- Contraindications: use with antacids.
- Side effects: increased creatinine kinase and depression or suicidal thoughts (especially in patients with pre-existing psychiatric conditions).
- Monitoring: HIV viral load, CD4 count, renal and hepatic function, and side effect development.
- If there’s resistance to the medications, viral load will increase before the CD4 count decreases
- Discontinuing INSTIs can exacerbate HBV.
- Medications must be taken exactly as prescribed; missing more than one dose per month can lead to serious resistance.
Nucleoside Reverse Transcriptase Inhibitors (NRTIs)
- NRTIs inhibit reverse transcriptase, incorporating into viral DNA and causing DNA chain termination.
- Examples: tenofovir (disoproxil fumarate/TDF or alafenamide/TAF), emtricitabine (FTC), lamivudine (3TC), abacavir (ABC), zidovudine (ZDV), didanosine (ddI), stavudine.
- Lamivudine and tenofovir are also used for Hepatitis B virus (HBV) treatment.
- Switching NRTI therapy requires careful planning for HBV treatment to avoid abrupt discontinuation.
- Contraindications: HLA-B*5701 allele (for abacavir) due to hypersensitivity risk.
- Side effects: Fanconi syndrome, decreased bone mineral density (increased with TDF), lactic acidosis, hepatomegaly with steatosis, nausea, vomiting, diarrhea, lipodystrophy (stavudine, didanosine, zidovudine).
- Monitoring: HIV viral load, CD4 count, renal and hepatic function, and side effect development.
- All NRTI agents carry the risk of lactic acidosis with hepatic steatosis.
Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs)
- NNRTIs inhibit reverse transcriptase and incorporates into viral DNA, resulting in DNA chain termination
- Examples: efavirenz, doravirine, etravirine, nevirapine, rilpivirine, delaviridine.
- Side effects: rash, increased LFTs, hyperlipidemia, QT interval prolongation, psychiatric issues (especially with efavirenz) like abnormal vivid dreams, agitation, depression, suicidal thoughts, and hallucinations.
- Monitoring: LFTs, rash, HIV viral load, CD4 count, renal and hepatic function, and side effect development.
- Efavirenz (EFV) was effective but is now less favored due to psychiatric side effects.
Fusion Inhibitors
- Fusion inhibitors block conformational changes in gp41, preventing HIV fusion with CD4 cell membranes, inhibiting entry and viral replication.
- Example: enfuvirtide.
- Side effects: local injection site reactions (pain, erythema, induration, nodules and cysts, pruritus, ecchymosis).
- Monitoring: HIV viral load, CD4 count, renal and hepatic function, and side effect development.
- Injections can cause severe local reactions.
Fusion/Entry Inhibitors
- Fusion/entry inhibitors bind to CD4 domain 2, interfering with post-attachment cell fusion and preventing viral transmission.
- Example: Ibalizumab-uiyk (monoclonal antibody).
- Monitoring: HIV viral load, CD4 count, renal and hepatic function, and side effect development.
- Used only in heavily treatment-experienced patients with multi-drug resistant viruses.
- These are not well tolerated
Protease Inhibitors (PIs)
- PIs bind to the active site of HIV protease, preventing mature virus particle formation.
- Examples: atazanavir, darunavir, fosamprenavir, indinavir, lopinavir/ritonavir, nelfinavir, ritonavir, tipranavir, and saquinavir.
- Contraindications: concurrent use CYP3A4 inhibitors and inducers and sulfa allergy (only with darynavir, fosamprenavir, and tipranavir).
- Side effects: metabolic syndrome (hyperlipidemia, hyperglycemia, insulin resistance, fat redistribution, increased CV risk, especially with atazanavir and darunavir) and hepatotoxicity.
- Drug interactions: avoid rifampin in TB patients; use rifabutin instead.
- PIs are no longer first-line therapy due to resistance issues and side effect profiles.
Cytochrome P450 Inhibitor ("Booster")
- A CYP3A4 inhibitor used to increase systemic exposure to CYP3A substrates, atazanavir, and darunavir.
- Example: cobicistat.
- Side effect: increases SCr/decreases CrCl (monitor closely if SCr increases by more than 0.4mg/dL )
- Drug interactions: CYP3A4 inhibitor.
- Used as an antiretroviral booster with atazanavir and darunavir.
CCR5 Inhibitors
- CCR5 inhibitors bind to CCR5 receptors, blocking HIV gp120 attachment and preventing cell entry.
- Example: maraviroc.
- Contraindications: CXCR4-tropic or dual/mixed-tropic HIV infection.
- Side effects: orthostatic hypotension and hepatotoxicity.
- Monitoring: HIV viral load, CD4 count, renal and hepatic function, and side effect development.
- Useful only for patients with CCR5-tropic HIV; tropism tested with coreceptor assay test (Trofile).
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