COVID-19 Antiviral Comparison Tool

Select an Antiviral to Compare

Molnupiravir has become a household name since the pandemic, but it’s not the only oral option for treating COVID‑19. If you’re trying to figure out which antiviral fits your situation, you need a side‑by‑side look at the major alternatives, their strengths, and their drawbacks. Below you’ll find a quick‑hit TL;DR, a deep dive into each drug, a comparison table, and a practical checklist to help you decide.

TL;DR

  • Molnupiravir: modest efficacy (≈30% reduction in hospitalization), easy 5‑day course, few drug interactions.
  • Paxlovid (nirmatrelvir/ritonavir): highest efficacy (≈89% reduction), needs dose‑adjustment for many meds, 5‑day course.
  • Remdesivir: IV infusion, 87% reduction in high‑risk outpatients, limited to infusion centers.
  • Best for: Paxlovid if no contraindicated meds; Molnupiravir if you can’t take Paxlovid; Remdesivir when IV access is possible and you need strong protection.
  • Cost & access: Paxlovid subsidised in many countries, Molnupiravir pricier in Australia, Remdesivir requires hospital/clinic procurement.

What is Molnupiravir?

Molnupiravir is a synthetic nucleoside analogue that introduces errors into the SARS‑CoV‑2 RNA genome, causing lethal mutagenesis. It was first approved in the UK in November 2021 and received FDA Emergency Use Authorization (EUA) in December 2021 for adults with mild‑to‑moderate COVID‑19 who are at risk of severe disease.

The drug is taken as 800mg (four 200mg capsules) twice daily for five days. Its oral route makes it attractive for people who can’t access infusion centers, but clinical trials showed only about a 30% reduction in hospitalization or death compared with placebo.

Why compare antivirals?

When COVID‑19 hit the mainstream, clinicians and patients faced three major questions:

  1. Which drug cuts the risk of severe disease the most?
  2. What side‑effects or drug interactions should I watch for?
  3. Can I actually get the drug where I live, and will my insurance cover it?

Answering these questions means looking at efficacy, safety, dosing convenience, cost, and regulatory status-all side by side.

Key comparison criteria

Below is a snapshot of the most relevant attributes for each antiviral. The numbers come from peer‑reviewed phaseIII trials, real‑world registries, and the latest prescribing information (as of September2025).

Efficacy, safety and practical factors of major COVID‑19 antivirals
Attribute Molnupiravir Paxlovid (nirmatrelvir/ritonavir) Remdesivir (IV)
Mechanism RNA‑directed mutagenesis Protease inhibition (Mpro) RNA‑dependent RNA polymerase inhibition
PhaseIII efficacy* (hospitalization/death) 30% relative risk reduction 89% relative risk reduction 87% relative risk reduction (outpatient IV)
Typical dosing 800mg PO BID ×5days 300mg nirmatrelvir + 100mg ritonavir PO BID ×5days 200mg IV daily ×3days
Key side‑effects Diarrhea, nausea, mild headache Altered taste, diarrhea, rare liver enzyme elevation Elevated transaminases, infusion‑site reactions
Major drug interactions None clinically significant Strong CYP3A4 inhibitors/inducers (e.g., statins, anti‑arrhythmics) Minimal oral interactions (IV only)
Contraindications Pregnancy (category X), severe renal impairment (eGFR <30) Severe liver disease, concomitant CYP3A4‑modulators eGFR <30mL/min, ALT >5×ULN
Regulatory status (2025) FDA EUA (pending full approval), TGA provisional approval FDA full approval, TGA listed FDA full approval for IV, oral formulation still in trials
Typical cost in Australia (AUD) ≈$650course ≈$450course (government subsidised) ≈$1,200course (hospital price)
Accessibility Pharmacy‑only, 2‑day delivery in major cities Pharmacy‑only, widely stocked in urban areas Requires infusion centre or hospital

*Relative risk reduction versus placebo in high‑risk, non‑hospitalised adults.

Deep dive into each alternative

Deep dive into each alternative

Paxlovid (nirmatrelvir/ritonavir)

Paxlovid is a fixed‑dose combination of the protease inhibitor nirmatrelvir and the pharmacokinetic booster ritonavir. The FDA granted full approval in July2023 after a large trial (EPIC‑HR) showed an 89% reduction in hospitalization or death for untreated high‑risk patients.

The drug’s biggest advantage is its efficacy, but the ritonavir component means it can interact with >50 common medicines - especially statins, anticoagulants, and some anti‑epileptics. Physicians must run a quick medication reconciliation before prescribing.

Renal dosing is simple: the standard dose for eGFR ≥60mL/min, and a 150mg/100mg dose for eGFR 30‑59mL/min. For eGFR <30mL/min, Paxlovid is not recommended.

Remdesivir (IV formulation)

Remdesivir was the first antiviral approved for COVID‑19 in 2020. While originally an inpatient treatment, a 2023 outpatient trial (PINETREE) demonstrated that a three‑day IV regimen cuts the risk of hospitalization by 87% in high‑risk adults.

Because it requires daily infusions, Remdesivir is best for patients who can access a hospital or dedicated infusion centre - for example, older adults living near a major city or those already in a health‑system network.

Side‑effects are mostly lab‑based (transaminase elevations). The drug is contraindicated in severe liver disease and eGFR <30mL/min.

Molnupiravir in context

Molnupiravir’s ease of use (plain capsules) makes it attractive for remote or rural settings where monitoring drug interactions is hard. Its modest efficacy is offset by the lack of CYP interactions, so it’s a fallback when Paxlovid isn’t an option.

Pregnant people should avoid Molnupiravir because animal studies showed potential teratogenic effects. In Australia, the Therapeutic Goods Administration (TGA) allows it only under strict risk‑benefit assessment.

Decision guide - which antiviral suits you?

  • High‑risk, no major meds: Paxlovid is the first‑line choice.
  • High‑risk, on CYP‑interacting meds: Switch to Molnupiravir if pregnancy isn’t a concern, or arrange IV Remdesivir if infusion is possible.
  • Renal eGFR 30‑59mL/min: Use reduced‑dose Paxlovid or Molnupiravir; avoid Remdesivir.
  • Severe liver disease: Remdesivir (monitor labs) or Molnupiravir (if not pregnant).
  • Limited pharmacy access (remote WA/NT): Molnupiravir is often the only oral agent stocked.

Practical prescribing checklist

  1. Confirm COVID‑19 positive test ≤5days from symptom onset.
  2. Identify high‑risk criteria (age≥65, immunosuppression, chronic lung disease, etc.).
  3. Run a quick medication review to catch CYP3A4‑modulators.
  4. Check renal (eGFR) and hepatic (ALT/AST) labs.
  5. Select the antiviral based on the decision guide above.
  6. Provide clear dosing instructions and counsel on side‑effects.
  7. Arrange follow‑up (telehealth or in‑person) within 48hours to monitor tolerance.

What about newer options?

By late 2025, oral monoclonal‑like agents (e.g., Sotrovimab‑oral) are still in PhaseIII, so they’re not yet in the comparison pool. Keep an eye on FDA announcements; the landscape may shift next year.

Frequently Asked Questions

Can I take Molnupiravir and Paxlovid together?

No. Both target the virus but work via different mechanisms, and combining them hasn’t been studied. Use one or the other based on the decision guide.

Is Paxlovid safe for people on statins?

Ritonavir can raise statin levels, increasing the risk of muscle toxicity. Doctors usually pause or switch to a low‑dose statin during the 5‑day Paxlovid course.

How quickly does Remdesivir work compared to oral pills?

IV delivery achieves higher plasma concentrations faster, so antiviral activity starts within hours. Oral agents reach peak levels in 2‑4hours, which is still effective but a bit slower.

What if I’m pregnant? Which antiviral is recommended?

Current guidelines advise against Molnupiravir in pregnancy. Paxlovid can be used after a risk‑benefit discussion, while Remdesivir is considered safe under close monitoring.

Are there any over‑the‑counter supplements that boost these antivirals?

No supplement has proven to enhance the efficacy of Molnupiravir, Paxlovid, or Remdesivir. Focus on getting the approved medication early and follow public‑health measures.

Next steps for patients and clinicians

Next steps for patients and clinicians

1. Verify the positive test date - treatment must start within five days of symptom onset. 2. Run the checklist above; if any red flag appears, flag the case for specialist review. 3. Contact your local pharmacy or hospital to confirm stock; in Perth, most major pharmacies carry Paxlovid and Molnupiravir, while Remdesivir is limited to hospital outpatient units. 4. Document the chosen antiviral, dosage, and any counseling given in the patient’s health record. 5. Schedule a follow‑up call to catch side‑effects early and adjust treatment if needed.