Antiviral Drugs

Nucleoproteins and Viruses

  • Nucleoprotein (RNA)

  • Lipid Envelope

  • Influenza Virus

  • Anatomy:

    • Neuraminidase (Sialidase)

    • Caps

    • Hemagglutinin

  • Antivirals

Definition of Viruses

  • Intracellular, submicroscopic parasites requiring a living cell to reproduce.

  • Two Types of Viruses:

    • Nonretrovirus: Easily spread and common.

    • Retrovirus: Not easily spread.

  • General treatment for viral infections is limited.

    • Nonretrovirus receives supportive treatment (e.g., RSV, West Nile Virus).

  • Common Question: Do antibiotics treat viruses?

    • No, antibiotics do not affect viruses.

Antiviral Therapy

  • Virustatic:

    • Antiviral drugs do NOT kill viruses but suppress viral replication and do not cure viral infections.

  • Intended Therapeutic Responses:

    • Shorten duration or severity of an active viral illness.

    • Prevent reactivation of dormant viruses.

    • Prevent viral replication to the point of disease.

  • Nursing Considerations:

    • Monitor for allergic reactions.

    • Medication must be taken exactly as prescribed.

    • Stopping early can lead to:

    • Symptom recurrence.

    • Development of resistant viruses.

  • NCLEX Pearl: Virustatic is not virucidal; adherence prevents resistance.

Influenza (Flu)

  • Caused by influenza viruses that are highly variable and constantly evolving.

  • Can lead to serious respiratory illness.

  • Major cause of morbidity and mortality worldwide.

  • Management & Prevention:

    • Managed through annual vaccination and antiviral medications.

    • Influenza vaccines change yearly based on circulating strains identified by:

    • CDC

    • FDA

    • WHO

  • Why Is the Flu Vaccine Needed Every Year?:

    • Frequent mutations of influenza viruses.

    • Antigenic drift changes surface proteins.

    • Immunity from prior infection or vaccination declines over time.

    • Circulating strains change each season.

Influenza Vaccine Types

  • Live Attenuated Influenza Vaccine (LAIV) – Nasal Spray

    • Who CAN get it:

    • Healthy individuals aged 2–49

    • FDA-approved for self or caregiver home administration.

    • Who should NOT get it:

    • Pregnant individuals (inactivated vaccine recommended).

    • Individuals <2 years or >49 years.

    • Immunocompromised patients.

    • Patients with severe respiratory disease.

    • Recent antiviral flu medication use (decreases effectiveness).

  • Inactivated Influenza Vaccine (IIV) – Shot

    • Available in standard and high-dose formulations.

    • High-Dose Vaccine: Recommended for those aged ≥ 65 to compensate for decreased immune response in older adults.

    • Who can get it:

    • Anyone aged ≥ 6 months.

  • Key Points:

    • Annual flu vaccination recommended for everyone aged ≥ 6 months.

    • Children 6 months–8 years require 2 doses 4 weeks apart if not fully vaccinated previously.

    • Primary prevention strategy.

  • NCLEX Pearls:

    • Nasal spray for healthy, non-pregnant individuals aged 2–49.

    • Shot for everyone aged ≥ 6 months.

    • Older adults may need a high-dose vaccine.

Vaccination Onset & Duration

  • Onset: Protection begins 1–2 weeks after vaccination.

  • Duration: Immunity lasts approximately 6 months or longer.

Precautions and Contraindications for Vaccination

  • History of severe allergic reaction to a prior flu vaccine.

  • History of Guillain-BarrĂ© syndrome within 6 weeks of a flu vaccine.

  • Egg allergy is NOT a routine exclusion anymore.

  • Defer vaccination during acute, severe febrile illness.

  • Minor illness (with or without fever) does NOT preclude vaccination.

  • Antibiotic use does not prevent vaccination.

  • Timing of Administration: Offer vaccination whenever influenza is circulating, typically during fall and winter months.

  • NCLEX Pearls:

    • Egg allergy is no longer a contraindication.

    • Immunocompromised patients should receive the flu shot, not the nasal spray.

    • Pregnant individuals require the flu shot only.

  • Most patients can safely receive the flu vaccine, even with minor illness or egg allergy.

Antiviral Drugs for Influenza

  • Neuraminidase Inhibitors: Treat influenza A & B.

    • Most effective if started ≤ 48 hours after symptom onset.

    • Can still be used later in severe illness or for hospitalized patients.

    • Shorten illness duration and reduce complications.

    • DO NOT replace the flu vaccine.

    • Example Drugs:

    • Oseltamivir: Available in PO (capsule or liquid), safe for children, older adults, and during pregnancy; preferred antiviral for hospitalized, pregnant, and high-risk patients.

    • Zanamivir: Powder inhalation via diskhaler; contraindicated in asthma or COPD due to risk of bronchospasm.

Side Effects and Patient Education

  • Oseltamivir & Zanamivir: Common Side Effects include GI upset (e.g., nausea, vomiting).

  • Adverse Effects: Rare in adults but may cause confusion or hallucinations in pediatric populations.

  • Patient Teaching:

    • Start antiviral therapy within 48 hours of symptom onset for best effectiveness.

    • Encourage seeking testing and treatment early.

    • Flu symptoms often appear suddenly and are severe.

    • Typical treatment duration: approximately 5 days.

    • Medications do not cure flu but shorten severity and duration.

  • Post-Exposure Use: Can be used for post-exposure prophylaxis indicated after close contact (e.g., household or family exposure).

Additional Antiviral Drug for Influenza

  • Baloxavir:

    • Used for treatment and post-exposure prophylaxis.

    • Available as a single-dose oral treatment, best started within 48 hours of symptom onset.

    • Side Effects: Mild gastrointestinal upset, headache, usually well tolerated.

  • NCLEX & Clinical Pearls:

    • Single-dose is a significant advantage over oseltamivir.

    • Not a substitute for the flu vaccine.

    • Does NOT treat COVID-19.

    • Starting after 48 hours of symptom onset = reduced benefit.

    • Recent use may interfere with live attenuated flu vaccine (nasal spray).

Comparative Overview of Influenza Drugs

  • Features:

    Drug

    Oseltamivir

    Zanamivir

    Baloxavir


    Drug Class

    Neuraminidase inhibitor

    Neuraminidase inhibitor

    Cap-dependent endonuclease inhibitor


    Route

    Oral (PO)

    Inhaled (Diskhaler)

    Oral (PO)


    Dosing

    Twice daily x 5 days

    Twice daily x 5 days

    Single dose


    Influenza Types

    A & B

    A & B

    A & B


    Best Timing

    ≤ 48 hrs (can use later if severe/hospitalized)

    ≤ 48 hrs

    ≤ 48 hrs ONLY


    Treatment Use

    Yes

    Yes

    Yes


    Prophylaxis Use

    Yes

    Yes

    Yes


    Key Adverse Effects

    N/V, rare neuropsychiatric effects in pediatrics

    Bronchospasm, cough

    Diarrhea, headache


    Major Contraindication

    None specific

    Asthma/COPD

    Avoid with dairy/minerals


    Pregnancy

    Preferred

    Avoid

    Not preferred

    • NCLEX Cue:

    • Oseltamivir = oral & safest

    • Zanamivir = inhaled, NO asthma/COPD

    • Baloxavir = single dose, early treatment only.

Topical Drugs for HSV (Herpes Simplex Virus)

  • Herpes labialis (cold sores – HSV-1):

    • Penciclovir: Topical cream effective for cold sores; best to start early (during prodrome) to shorten healing time; minimal systemic absorption.

    • Acyclovir: Available orally or topically; systemic or topical antiviral used for more severe or recurrent outbreaks; effectiveness increases with early treatment; does not cure herpes but suppresses replication.

  • Cold Sores: Treated with topical or oral antivirals.

  • Eye Involvement: Requires use of ophthalmic antivirals and urgent care.

  • Ocular herpes infections (HSV keratitis):

    • Trifluridine: Ophthalmic drops effective for HSV keratitis but can be toxic to corneal cells; use short-term only.

    • Acyclovir ophthalmic ointment: Alternative or adjunct to drops for ocular HSV.

Hepatitis and Liver Function

Primary Prevention

  • Most effective prevention strategy is vaccination.

Treatment Goals (for Hepatitis B)

  • Prevent disease progression and reduce the risk of cirrhosis, liver failure, and hepatocellular carcinoma.

Acute Hepatitis B Treatment

  • Most patients clear the virus spontaneously.

  • Treatment is primarily supportive for managing symptoms:

    • Manage nausea.

    • Maintain hydration.

    • Avoid hepatotoxic substances like alcohol and acetaminophen.

    • Antiviral therapy is not routinely indicated.

  • NCLEX Pearl:

    • Acute Hep B = supportive care; Chronic Hep B = antiviral therapy.

    • Best prevention = vaccination.

Chronic Hepatitis B

  • Chronic infection defined as HBsAg positive for over 6 months; < 5% of HBV infections become chronic.

  • Risks associated with chronic HBV include cirrhosis and liver failure.

  • Example Drugs:

    • Interferon:

    • Injectable immune-modulating antiviral.

    • Adverse effects may include flu-like symptoms, GI upset, and mood changes (monitor for depression/suicidal ideation).

    • Entecavir:

    • Oral antiviral with strong activity and low resistance potential.

    • Long-term therapy often required (≥ 12 months).

    • Black Box Warning: Severe HBV flare if stopped abruptly; avoid in patients with HIV.

Nursing Considerations for Chronic Hepatitis B

  • Assess adherence to long-term therapy.

  • Monitor liver function tests and clinical signs of decompensation.

  • Educate patients not to stop entecavir abruptly.

  • Screen for depression/mood changes in those on interferon.

  • Reinforce follow-up labs and appointments.

  • NCLEX Takeaways:

    • Chronic HBV must be diagnosed > 6 months.

    • Mood effects of interferon require monitoring.

    • Abrupt cessation of entecavir can be dangerous.

Hepatitis C

Treatment Selection

  • May vary by genotype (provider-determined).

  • Acute HCV is treated with direct-acting antivirals (DAAs) due to public health benefits.

    • 20–50% of patients may spontaneously clear infection, with early treatment yielding higher cure rates.

  • Direct-acting Antivirals (DAAs):

    • First-line therapy for HCV targeting enzymes critical for replication.

    • Goal is cure, defined as Sustained Virologic Response (SVR).

    • Example Drugs:

    • Sofosbuvir/Velpatasvir: 12-week treatment course.

    • Glecaprevir/Pibrentasvir: 8-week treatment course.

    • Older Therapies: Interferon and ribavirin, which had higher toxicity and are rarely used today.

Administration Considerations

  • Cure rates are higher in patients without cirrhosis.

  • Monitor liver and kidney function during treatment (e.g., AST, ALT, creatinine).

  • Emphasize the importance of completing the full course of treatment.

Retroviruses

Human Immunodeficiency Virus (HIV)

  • Retrovirus with RNA as genetic material utilizing reverse transcriptase to convert RNA into DNA and insert viral DNA into host DNA.

  • Targets CD4 T cells (helper lymphocytes).

  • Transmitted through blood and body fluids; highly efficient infection can occur even with low viral exposure.

  • NCLEX Pearls:

    • Loss of CD4 cells leads to immunosuppression.

    • Reverse transcriptase is a key drug target.

HIV as a Chronic Disease

  • With effective antiretroviral therapy (ART), HIV is manageable as a chronic condition requiring lifelong treatment and follow-up.

  • Healthy Lifestyle Considerations include:

    • Balanced diet, regular exercise, smoking cessation, limited alcohol use, stress management, and routine preventive care/immunizations.

  • Management of Comorbid Conditions common in HIV patients:

    • Diabetes mellitus (DM), Hypertension (HTN), Coronary artery disease (CAD), Dyslipidemia, obesity.

    • Nursing focus:

    • Monitor drug–disease and drug–drug interactions.

    • Encourage adherence to both ART and chronic disease therapies.

    • Coordinate care across specialties.

  • NCLEX Pearls:

    • HIV care involves chronic disease management.

    • ART may increase the risk for cardiovascular and metabolic conditions.

    • Lifestyle modification is as important as medication adherence.

HIV Pre-exposure Prophylaxis (PrEP)

Assessing HIV Risk & Candidates

  • Risk Assessment: Obtain sexual history and assess for substance use and injection drug use.

  • Populations Who Benefit from PrEP:

    • Individuals with a sexual partner with HIV (detectable or unknown viral load).

    • Men who have sex with men (MSM).

    • Transgender women engaging in high-risk sexual behaviors (e.g., condomless anal sex).

    • People who inject drugs.

    • Heterosexually active individuals with partners at high risk for HIV.

    • Individuals living in high-prevalence regions.

  • NCLEX Pearls:

    • PrEP is preventive, NOT treatment.

    • Requires confirmed HIV-negative status prior to starting, with ongoing risk assessments and follow-up testing.

PrEP Example Drugs

  • TDF-FTC (Truvada):

    • Tenofovir disoproxil fumarate-emtricitabine is the first-line PrEP for most patients, well tolerated as an oral treatment.

    • Black Box Warning: Acute hepatitis B exacerbation if stopped abruptly; risk of drug resistance if used in undiagnosed HIV infection.

  • Cabotegravir:

    • Long-acting injectable PrEP, alternative for patients struggling with daily oral therapy.

  • Considerations:

    • Confirm HIV-negative status before starting PrEP.

    • Testing should occur within 1 week prior to initiation and every 3 months while on PrEP.

    • PrEP does NOT treat HIV; it is used solely for prevention.

  • NCLEX Pearls:

    • Do not start PrEP without confirming HIV status.

    • Monitor adherence and follow-up labs.

MMWR on PrEP

  • PrEP is a powerful method for preventing HIV transmission.

  • Daily use of PrEP dramatically reduces risk of acquiring HIV through sex.

  • More PrEP Use is Needed:

    • Increased from 6% to 35% among MSM.

    • PrEP use remains low, particularly among Black and Hispanic MSM.

  • Healthcare Providers Role:

    • Test for HIV, assess patient risk, and prescribe PrEP as needed using CDC resources.

Post-Exposure Prophylaxis (PEP)

Definition of PEP

  • Emergency HIV prevention treatment initiated after known or possible exposure; must commence within 72 hours for effectiveness.

  • Who Needs PEP?:

    • Occupational exposure (e.g., needlestick).

    • Sexual exposure to someone with HIV or unknown status.

    • Exposure to blood or body fluids (e.g., mucous membranes, non-intact skin).

PEP Regimen

  • Combination therapy required with a typical regimen:

    • Tenofovir disoproxil fumarate / Emtricitabine (TDF-FTC) + an integrase inhibitor.

    • Duration: 28 days.

  • Key Nursing Considerations:

    • Start ASAP (do not wait for test results).

    • Obtain baseline HIV test before starting and follow-up testing at 4–6 weeks, 3 months, and 6 months.

    • Reinforce adherence to complete the full 28-day course.

    • Monitor for side effects and lab results.

  • NCLEX Pearls:

    • PEP ≠ PrEP (PEP is for immediate prevention post-exposure, while PrEP is for ongoing prevention).

Classes of Antiretroviral Drugs

  • Reverse Transcriptase Inhibitors:

    • Nucleoside analog reverse transcriptase inhibitors (NRTIs).

    • Non-nucleoside analog reverse transcriptase inhibitors (NNRTIs).

  • Protease Inhibitors (PIs).

  • Fusion Inhibitors.

  • Entry Inhibitors.

  • Integrase Inhibitors.

Antiretroviral Therapy Overview

  • Antiretroviral therapy is virustatic, suppressing viral replication without curing HIV, and is typically administered as combination therapy (“cocktail”).

  • Also known as HAART (Highly Active Antiretroviral Therapy).

  • Intended Response:

    • Achieve undetectable viral load (<20 copies/mL).

    • Stabilize or increase CD4 count (minimum critical threshold: ≥200 cells/mmÂł to prevent opportunistic infections).

    • The trend over time is more important than a single value.

  • Nursing Considerations:

    • Strict adherence is critical to avoid resistance.

    • Monitor for allergic reactions (e.g., rash, fever).

    • Lab monitoring (e.g., viral load, CD4 count) is crucial.

    • Reinforce that undetectable does NOT mean cured; the goal is viral suppression.

    • HAART must be taken lifelong, and skipping doses increases resistance risk.

NRTIs (Nucleoside Reverse Transcriptase Inhibitors)

Mechanism of Action

  • Block reverse transcriptase to inhibit viral DNA synthesis.

Example Drug

  • Zidovudine (AZT):

Common Side Effects

  • Headache, malaise.

  • Nausea, GI upset (worse with fatty foods).

Adverse Effects

  • Peripheral neuropathy (monitor symptoms and provide safety teaching).

  • Pancytopenia (review this condition with considerations and teaching).

  • Lactic acidosis (especially in pregnancy).

  • Hepatomegaly.

Patient Teaching

  • Take exactly as prescribed.

  • Report troubling symptoms such as numbness/tingling, severe fatigue, or abdominal pain.

  • Do not stop therapy abruptly.

NNRTIs (Non-nucleoside Reverse Transcriptase Inhibitors)

Mechanism of Action

  • Directly inhibit reverse transcriptase.

Example Drugs

  • Efavirenz:

Adverse Effects

  • Rash (can be severe).

  • CNS effects (vivid dreams, dizziness).

  • Hepatotoxicity.

Patient Teaching

  • Report rash or any symptoms suggestive of liver issues.

  • Notify the prescriber if developing sore throat, fever, unusual rashes, blisters, or extensive bruising.

  • Recommended to take at bedtime if CNS effects occur.

PIs (Protease Inhibitors)

Mechanism of Action

  • Block protease enzyme, preventing viral maturation.

Example Drug

  • Ritonavir:

Common Side Effects

  • GI upset is common.

Adverse Effects

  • Hyperglycemia.

  • Dyslipidemia.

  • Fat redistribution.

Patient Teaching

  • Monitor glucose and lipids closely.

  • Check with the provider before taking any other medications due to numerous drug interactions.

Fusion Inhibitors

Mechanism of Action

  • Block entry of HIV into CD4 T cells.

Example Drug

  • Enfuvirtide (Fuzeon):

Side Effects

  • Injection site reactions (subcutaneous).

Adverse Effects

  • Peripheral neuropathy.

  • Increased respiratory infections, hepatotoxicity.

Patient Teaching

  • Educate on storage, handling, and self-injection techniques.

  • Inform about respiratory infection signs and symptoms and monitor injection sites for infections.

Entry Inhibitors

Mechanism of Action

  • Blocks the CCR5 receptor on CD4+ T-cells.

Example Drug

  • Maraviroc:

Side Effects

  • Myalgia, insomnia.

Adverse Effects

  • Hypotension, liver toxicity.

Patient Teaching

  • Educate on managing potential hypotension and hepatotoxicity risks.

Integrase Inhibitors

Mechanism of Action

  • Block integration of viral DNA into host DNA.

Examples

  • Dolutegravir:

Side Effects

  • Headache, insomnia, weight gain (in some patients).

Patient Teaching

  • Separate from antacids/minerals for better absorption.

  • Generally well tolerated.

Lifespan Considerations in Antiretroviral Therapy

Pediatrics

  • Weight-based dosing; drug selection and dosing vary by medication.

  • Close monitoring of growth, adherence, and labs is required.

Pregnancy & Breastfeeding

  • ART is recommended for pregnant patients; drug choice varies.

  • Many NRTIs, PIs, and INSTIs are considered safe and effective.

  • Some agents may be initiated after the first trimester, with the goal of maternal viral suppression to minimize transmission risks.

Older Adults

  • NRTIs: Risk of peripheral neuropathy may present more quickly.

  • Risk of polypharmacy increases chances of drug–drug interactions.

  • Increased risk of falls due to orthostatic hypotension.

  • Integrase inhibitors may require monitoring for interactions with statins.

  • NCLEX Pearls:

    • ART selection must be individualized based on age, pregnancy status, and comorbidities, also assessing potential drug interactions and adverse effects.

HIV Treatment in Pregnancy and Pediatrics

Pregnancy

  • Same ART principles as for non-pregnant adults; ART is endorsed for all pregnant patients with HIV; the objective is to achieve undetectable viral load.

  • Surveillance of maternal viral load significantly diminishes transmission risk from mother to child.

Pediatrics

  • ART principles apply with individual therapy developed by age and weight.

  • Objectives remain viral suppression and immune protection for the child.

  • NCLEX Pearls:

    • Viral load is the best predictor of transmission risk.

    • ART benefits both mother and infant, with earlier treatment leading to improved outcomes.

Post-Exposure Prophylaxis Considerations

  • Prophylactic medications reduce HIV infection risk when started within 72 hours of accidental exposure.

  • Occupational exposures require prompt treatment.

  • Advanced HIV Disease: Patients with low CD4 counts are at increased risk for opportunistic infections, making prophylactic antibiotics essential.

  • Pneumocystis Pneumonia (PCP): A common, potentially fatal opportunistic infection that occurs when CD4 < 200 cells/mmÂł; prophylaxis is indicated at low CD4 levels.

  • NCLEX Pearls:

    • CD4 count drives prophylaxis decisions; preventing infection is a key nursing priority.

COVID-19 Treatment Strategies

Outpatient Treatment

  • Goals: Prevent progression and hospitalization.

  • Drug Therapy:

    • Antivirals (initiated early):

    • Nirmatrelvir/ritonavir (Paxlovid): to be started within 5 days of symptom onset.

    • Remdesivir (IV): outpatient option for select patients.

    • Supportive Care:

    • Antipyretics, fluids, and rest.

    • High-risk patients are prioritized (e.g., older age, chronic disease, immunocompromised).

Inpatient Treatment

  • Goals: Treat hypoxia and severe inflammation.

  • Supportive Care:

    • Oxygen therapy.

    • Drug Therapy:

    • Antivirals: Remdesivir (IV)

    • Anti-inflammatory Therapy: Dexamethasone indicated if oxygen is required.

    • Monitoring for complications like ARDS and sepsis.

COVID-19 NCLEX Pearls

  • Antivirals work best when initiated early.

  • Corticosteroids are indicated only for patients needing oxygen support.

  • Supportive care is vital in both settings; outpatient care focuses on early antiviral use and preventing progression while inpatient care emphasizes oxygen support and managing inflammation and complications.

Nursing Statements on ART Goals

  • A patient newly diagnosed with HIV and starting ART should understand that combination therapy aims to suppress viral replication and reduce resistance instead of eliminating HIV or stopping treatment upon symptom improvement.

Questions and Answers

First Response

  • Correct answer: C (Combining drugs suppresses viral replication and reduces resistance)

Managing Peripheral Neuropathy

  • The nurse should assess the patient for peripheral neuropathy and notify the provider, especially if the patient reports numbness and tingling in both feet.

Patient Education on ART

  • Key talking points include: ART must be lifelong, and missing doses can result in drug resistance; be aware of common drug interactions; understand that CD4 counts often improve after viral load decreases, and undetectable loads do not equate to a cure

Treatment Plans for Patients with COVID-19

Appropriate Interventions

  • Administer dexamethasone to a patient requiring supplemental oxygen.

  • Remember to start antiviral therapy early in high-risk outpatients and provide supportive care for fluids and antipyretics.

  • Avoid antivirals in hospitalized patients where the focus should be on supporting oxygen delivery and addressing inflammation.

Conclusion

  • Focus on lifelong prevention and treatment for viral infections, ensuring education regarding medications, and assessing for specific contraindications and interactions is essential for patient safety, particularly in cases such as HIV and influenza.