ARVs DRUG CLASSES

 ARVs DRUG CLASSES

Here are detailed notes on ARV drug classes, their side effects, and Differentiated Service Delivery (DSD) models for treatment and care:

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ARV Drugs: Classes and Side Effects

Antiretroviral (ARV) drugs are used to manage HIV/AIDS by reducing the viral load and preventing disease progression. They are classified into several classes based on their mechanism of action.

Classes of ARV Drugs

1. Nucleoside Reverse Transcriptase Inhibitors (NRTIs):

   • Examples: Zidovudine (AZT), Lamivudine (3TC), Tenofovir (TDF), Emtricitabine (FTC).
   • Mechanism: Inhibits reverse transcriptase by incorporating faulty nucleotides, halting viral replication.
   • Side Effects: Anemia, lactic acidosis, lipodystrophy, nephrotoxicity (e.g., TDF), nausea, and headache.

2. Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs):

   • Examples: Efavirenz (EFV), Nevirapine (NVP), Etravirine (ETR).
   • Mechanism: Binds directly to reverse transcriptase, causing conformational changes that prevent its activity.
   • Side Effects: Rash, hepatotoxicity, vivid dreams (EFV), and central nervous system effects.

3. Protease Inhibitors (PIs):

   • Examples: Lopinavir/ritonavir (LPV/r), Atazanavir (ATV), Darunavir (DRV).
   • Mechanism: Inhibits viral protease enzymes, preventing maturation of viral particles.
   • Side Effects: Hyperlipidemia, lipodystrophy, diarrhea, nausea, and insulin resistance.

4. Integrase Strand Transfer Inhibitors (INSTIs):

   • Examples: Raltegravir (RAL), Dolutegravir (DTG), Bictegravir (BIC).
   • Mechanism: Blocks integrase, preventing integration of viral DNA into the host genome.
   • Side Effects: Insomnia, headache, and rare hypersensitivity reactions.

5. Entry Inhibitors:

   • Examples: Maraviroc (CCR5 antagonist), Enfuvirtide (fusion inhibitor).
   • Mechanism: Prevents HIV entry into host cells by blocking coreceptor binding or fusion.
   • Side Effects: Injection site reactions (Enfuvirtide), cough, fever, and liver toxicity (Maraviroc).

6. Post-Attachment Inhibitors:

   • Example: Ibalizumab.
   • Mechanism: Blocks HIV from entering CD4 cells after attachment.
   • Side Effects: Diarrhea, rash, and immune reconstitution syndrome.

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Differentiated Service Delivery (DSD) Models

The DSD model is a patient-centered approach to HIV care, emphasizing efficiency and improving patient outcomes by tailoring services to individual needs.

Key Components of DSD Models

1. Client-Centered Care:
   Tailored to meet the unique needs of different groups, such as stable patients, children, adolescents, or key populations.

2. Community-Based Services:
   Expands care delivery to the community level, reducing the burden on health facilities.

3. Decentralized Drug Delivery:
   Includes multi-month dispensing (MMD) and community drug distribution points to improve access.

4. Multi-Disciplinary Teams:
   Engages healthcare workers, peer educators, and community health volunteers in comprehensive care.

DSD Model Types

1. Facility-Based Models:

   • Example: Fast-track refills, ART clubs within clinics.
   • Target Group: Stable patients needing minimal interaction with healthcare providers.

2. Community-Based Models:

   • Example: Community ART refill groups (CARGs).
   • Target Group: Patients far from healthcare facilities or those with limited mobility.

3. Mobile Clinics:

   • Example: Services delivered in hard-to-reach areas using mobile units.
   • Target Group: Patients in remote or underserved regions.

4. Key Population Models:

   • Example: Specialized clinics for sex workers, men who have sex with men (MSM), or injecting drug users.
   • Target Group: Key populations facing stigma or discrimination.

Benefits of DSD Models

• Reduces patient waiting times and travel costs.\n- Improves adherence and retention.\n- Increases health system efficiency by focusing on those with more complex needs.

Challenges of DSD Models

• Limited resources for community-based care.\n- Training and supervision of community healthcare workers.\n- Ensuring consistent supply chains for ARVs.

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