Antivirals (non-HIV)

Antivirals (non-HIV)

Drug monograph · NCLEX study reference
Therapeutic class	Antiviral
Pharmacologic class	Nucleoside analogs and others by target
Onset / peak / duration	Best when started early (oseltamivir within 48 hours of flu symptoms).
Half-life / level	Varies; no routine level.
Routes	PO (oral), IV
High-alert (ISMP)	No
Black box warning	Yes (see Safety)
Antidote / reversal	Supportive care.
Pregnancy / lactation	Ribavirin contraindicated; others case by case.

Nursing pharmacology study reference (NCLEX-style monograph). Numeric values are standard teaching ranges for study and must be verified against current manufacturer labeling before clinical use. This is educational content, not prescribing guidance.

Antivirals (non-HIV) — Antiviral; Nucleoside analogs and others by target.

Identification

• Therapeutic class: Antiviral.
• Pharmacologic class: Nucleoside analogs and others by target.

Pharmacology

• Mechanism of action: Inhibit viral replication (acyclovir and valacyclovir target herpes DNA polymerase; oseltamivir inhibits influenza neuraminidase; nirmatrelvir inhibits the SARS-CoV-2 protease boosted by ritonavir; ganciclovir targets CMV; ribavirin and direct-acting agents target their respective viruses).
• Onset / peak / duration: Best when started early (oseltamivir within 48 hours of flu symptoms).
• Half-life / therapeutic level: Varies; no routine level.

Clinical use

• Indications: Herpes simplex and zoster (acyclovir, valacyclovir), influenza (oseltamivir), COVID-19 (nirmatrelvir/ritonavir), CMV (ganciclovir), hepatitis C (sofosbuvir-based) and hepatitis B (entecavir, tenofovir).
• Usual dose, route, frequency: Acyclovir PO five times daily or IV; valacyclovir PO; oseltamivir twice daily for 5 days; nirmatrelvir/ritonavir twice daily for 5 days.
• Maximum dose / adjustments: Reduce acyclovir, valacyclovir, and oseltamivir in renal impairment; maintain hydration with IV acyclovir.

Safety

• Contraindications: Hypersensitivity; nirmatrelvir/ritonavir has many drug interaction contraindications.
• Black box warning: Ganciclovir and valganciclovir carry boxed warnings for hematologic toxicity (granulocytopenia, anemia, thrombocytopenia) and carcinogenic and teratogenic potential; ribavirin carries boxed warnings for hemolytic anemia and serious teratogenicity (pregnancy contraindicated for the patient and partner).
• Interactions: Nirmatrelvir/ritonavir interacts with many CYP3A4 drugs (statins, some anticoagulants, sedatives); nephrotoxic drugs with acyclovir.
• Pregnancy / lactation: Ribavirin contraindicated; others case by case.
• High-alert: No.

Adverse effects

• Common side effects: Nausea, headache, dizziness.
• Serious effects to report: Acyclovir nephrotoxicity and neurotoxicity, ganciclovir marrow suppression, ribavirin anemia, drug interactions with nirmatrelvir/ritonavir.
• Antidote / reversal: Supportive care.

Nursing process

• Assessment before administration: Renal function, hydration, full medication list (interactions), pregnancy status (ribavirin).
• Interventions during therapy: Hydrate well with IV acyclovir; review all interacting drugs before nirmatrelvir/ritonavir; start flu and COVID antivirals early.
• Monitor: Renal function, CBC (ganciclovir, ribavirin), infection course.
• Evaluation / expected outcome: Reduced viral illness severity or duration.

Patient teaching

• Patient teaching: Start early; stay hydrated; report decreased urination; strict contraception with ribavirin.
• Notify provider if: Decreased urination, confusion, easy bruising, severe fatigue.
• Administration tips: Maintain hydration; check interactions; begin promptly.