Antiviral drugs

There is no globally recognised antiviral drug that is effective for treatment. Remdensivir and molnupiravir show moderate efficacy.

Antiviral drugs are hard to find because of the diversity and cell-parasitic nature of viruses. It has taken a long time to find effective drugs for HIV or hepatitis C. The challenge is to find a therapeutic dose window between the side effects of antiviral drugs and their effect against the viral disease.
The main targets are the specific viral enzymes: RNA-dependent RNA polymerase and the two proteases.

External resource

Infectious Diseases Society of America (IDSA) guidelines for treatment and management of patients with COVID-19

IDSA treatments PDF


ANTIVIRAL DRUGS This table displays the main drugs investigated

Compound Class Ref Status for Covid-19 Notes
Paxlovid (Nirmatrelvir
Ritonavir )
Protease inhibitor/CYP3A inhibitor (respectively) Approved.
Effective in clinical trials
-Oral SARS-CoV-2 M pro inhibitor. Nirmatrelvir is responsible for the antiviral activity of the medication while ritonavir is stabilizing its action by inhibiting CYP3A4, the cellular enzyme that metabolizes Nirmatrelvir.
Remdesivir Viral polymerase inhibitor Approved. Weakly effective in clinical trials -
(MK-4482 or EIDD-2801)
Viral polymerase inhibitor Approved .
Weakly effective in clinical trials
-Repurposed: Nucleotide analog designed against Influenza.
Bemnifosbuvir (AT-527) Viral polymerase inhibitor Under investigation - Nucleotide analog that inhibits viral polymerase at two regions.
Fluvoxamine Unknown Rejected for COVID-19 treatment. -Repurposed: antidepressant of the selective serotonin reuptake inhibitor (SSRI) class
Invermectin Unknown No evidence of SARS-CoV-2 inactivation -Repurposed: Inhibits glutamate-gated chloride channels common to invertebrate nerve and muscle cells.
Favipiravir Viral polymerase inhibitor No evidence of SARS-CoV-2 inactivation -Repurposed
Ritonavir , Lopinavir Protease inhibitor No-benefit in clinical trials -Repurposed: Molecules targeting HIV protease which is a ASP protease, but SARS-Cov proteases are THIOL proteases.
Darunavir Protease inhibitor No evidence of SARS-CoV-2 inactivation -Repurposed
Camostat Spike maturation inhibitor -TMPRSS2 inhibitor that may prevent Spike cleavage and activation. Spike could still be activated by cathepsin or furin
Hydroxychloroquine Endosome fusion inhibitor No-benefit in clinical trials
-Repurposed: Non-specific anti-malaria drug. May prevent virus entry by modifying endosomal pH.
Umifenovir/Arbidol Endosome fusion inhibitor No-benefit in clinical trials -Repurposed: Anti influenza drug
Ronza Najjar-Debbiny, Naomi Gronich, Gabriel Weber, Johad Khoury, Maisam Amar, Nili Stein, Lee Hilary Goldstein, Walid Saliba Effectiveness of Paxlovid in Reducing Severe COVID-19 and Mortality in High Risk Patients
Clin Infect Dis. 2022 Jun 2
FDA Food and drugs administration.
Memorandum Explaining Basis for Declining Request for Emergency Use Authorization of Fluvoxamine Maleate