A 58-year-old man with type 2 diabetes mellitus presents with a 5-day history of fever, cough, and dyspnea. RT-PCR for SARS-CoV-2 is positive. Chest X-ray shows bilateral ground-glass opacities. SpO₂ is 88% on room air. He has no contraindications to antivirals. What is the drug of choice for treatment of this moderate COVID-19?

Explanation

## Antiviral Choice in Moderate COVID-19 **Key Point:** Remdesivir is the WHO-recommended and FDA-approved nucleotide analog reverse transcriptase inhibitor (nRTI) for moderate-to-severe COVID-19 requiring supplemental oxygen. ### Mechanism of Action Remdesivir is a prodrug that is metabolized intracellularly to an active nucleoside triphosphate, which inhibits SARS-CoV-2 RNA-dependent RNA polymerase (RdRp), causing chain termination. ### Clinical Evidence & Indications | Feature | Remdesivir | Molnupiravir | Paxlovid | Favipiravir | |---------|-----------|-------------|---------|-------------| | **MOA** | nRTI (RdRp inhibitor) | Nucleoside analog (mutagenic) | Protease inhibitor | RdRp inhibitor | | **Stage of disease** | Moderate–severe (hypoxia) | Mild–moderate (early) | Mild–moderate (early, high-risk) | Mild–moderate (early) | | **Route** | IV (5–10 days) | Oral (5 days) | Oral (5 days) | Oral (5 days) | | **Efficacy in moderate** | ↓ hospitalization & mortality | Limited data in moderate | Not primary choice for moderate | Limited evidence | | **Contraindications** | eGFR <30 (relative) | Pregnancy, teratogenic | CKD (dose adjust), drug interactions | Pregnancy | **High-Yield:** This patient has **moderate COVID-19** (SpO₂ 88%, bilateral infiltrates, day 5 of illness). Remdesivir is the standard of care for this severity level and has demonstrated a reduction in time to clinical improvement and mortality in the ACTT-1 and ACTT-2 trials. ### Why Remdesivir Here 1. **Hypoxia present** (SpO₂ 88%) → indicates moderate disease requiring IV therapy 2. **Timing** (day 5) → still within the window for antiviral efficacy 3. **Guideline recommendation** → WHO, FDA, and Indian Council of Medical Research (ICMR) recommend remdesivir for moderate–severe COVID-19 **Clinical Pearl:** Remdesivir is administered as a 200 mg IV loading dose on day 1, followed by 100 mg IV daily for 4–9 days (typically 5 days total). It must be given early (ideally within 10 days of symptom onset) to maximize benefit. **Warning:** Do not confuse remdesivir's indication with oral antivirals (molnupiravir, paxlovid), which are reserved for **mild-to-moderate disease in high-risk patients** and are most effective when started within 5 days of symptom onset in the outpatient/early hospitalization setting.