They kill or inhibit the growth of viruses.
| Antiviral | Mechanism of action | Use | Adverse effect |
| Drugs used in the treatment of influenza | |||
| Amantadine | Interferes with uncoating of viral RNA by blocking the M2 ion channel | Influenza A (widespread resistance common); Parkinson’s disease | Insomnia, seizures, anorexia |
| Oseltamivir (Tamiflu) | Prodrug, activated by esterases, inhibition of viral neuraminidase which inhibits the release of virus particles from host cells | Influenza A and B, decreases the severity and duration of symptoms if taken within 48 hours of symptom onset | Bronchitis, insomnia, nausea, vertigo, vomiting |
| Zanamivir (relenza) | inhibition of viral neuraminidase which inhibits the release of virus particles from host cells | Influenza A and B, administered by inhalation, use within 48 hours | Bronchospasm, nasal and throat discomfort |
| Rapivab (peramivir) | inhibition of viral neuraminidase which inhibits the release of virus particles from host cells | Influenza A and B, by intravenous infusion, use within 48 hours | Diarrhea, neutropenia, elevated glucose, elevated liver enzymes, hypersensitivity |
| Xofluza or baloxavir | Prodrug, baloxavir inhibits the endonuclease activity of PA protein and inhibits viral replication | Influenza A and B; Use within 48 hours of symptom onset | Diarrhea, nausea, headache, nasopharyngitis, bronchitis |
| Drugs used in the treatment of HSV, VZV and CMV | |||
| Acyclovir | Guanosine analogue that is acted upon by viral thymidine kinase and further activated by human enzymes to the active form that inhibits viral DNA polymerase | Herpes zoster, genital herpes, HSV encephalitis and VZV (varicella zoster) | Phlebitis, nausea, headache, malaise, renal insufficiency, encephalopathy; Probenecid delays the elimination of acyclovir |
| Valacyclovir | Prodrug, converted in the body to acyclovir, rest action same as acyclovir | Herpes zoster, genital herpes, herpes labialis | TTP, HUS, renal insufficiency |
| Ganciclovir | Activated by viral thymidine kinase and further activated by human enzymes to the active form that inhibits viral DNA polymerase | CMV retinitis | Myelosuppression, CNS toxicity , teratogenicity, pancreatitis |
| Valganciclovir | Prodrug of ganciclovir, same mechanism as ganciclovir | CMV retinitis | Myelosuppression, CNS toxicity , teratogenicity, pancreatitis |
| Foscarnet | An inorganic pyrophosphate that competes with viral enzymes for the binding site and inhibits them. Enzymes inhibited include viral DNA polymerase, RNA polymerase and HIV reverse transcriptase | Immunocompromised patients with CMV retinitis, mucocutaneous HSV infections, acyclovir resistant HSV and VZV infections | Renal insufficiency, seizures, electrolyte imbalance, nausea, headache, diarrhea, hematologic disturbances |
| Cidofovir | Nucleotide analogue that inhibits viral DNA polymerase | CMV retinitis in AIDS, HSV | Nephrotoxicity, neutropenia, thrombocytopenia |
| Drugs used in the treatment of hepatitis viruses and Ribavirin | |||
| Ribavirin | Riboside analogue converted to triphosphate form that inhibits viral RNA polymerase and inhibits capping of viral mRNA. It also inhibits viral inosine monophosphate dehydrogenase in HCV and inhibits viral replication | RSV, HCV | Respiratory distress, hemolytic anemia, cough, pruritus, rash, contraindicated in pregnancy due to teratogenicity |
| Palivizumab | Humanized monoclonal antibody against F glycoprotein of RSV, prevents viral invasion of host cells | Used for prophylaxis of RSV in high risk infants like those with chronic lung disease, congenital heart disease and immunodeficiencies; It cannot treat RSV infection | Local erythema, pain, fever, rash, rarely anaphylaxis |
| Adefovir | Blocks HBV reverse transcriptase | Chronic HBV | Asthenia, nephrotoxicity, elevated liver enzymes, headache, nausea, lactic acidosis, liver failure, fatty liver, may develop resistance to HIV drugs (RTIs) |
| Entecavir | Guanosine analogue that blocks HBV polymerase | Chronic HBV | Hepatotoxicity, elevated liver enzymes, fatty liver, lactic acidosis, may develop resistance to HIV RTIs |
| Pegylated Interferon alpha-2a and 2b | Binds to and activates human type 1 interferon receptors on hepatocytes which activates intracellular signal transduction pathways that increase gene expression leading to the inhibition of viral replication, augments host antiviral responses, degrades viral mRNA by activating ribonucleases, blocks protein synthesis by inhibition of translation and initiation complex formation | HBV and HCV, RSV, Kaposi’s sarcoma in AIDS and malignant melanoma; Newer and safer drugs are preferred over peg IF alpha | Flu-like symptoms, arrhythmias, tachycardia, cardiomyopathy, thyroid dysfunction, hepatotoxicity, photosensitivity, myelosuppression, depression, renal insufficiency |
| Sofosbuvir | Prodrug, converted by hepatic cellular kinases to active form; uridine nucleotide analogue, inhibitor of HCV polymerase thus inhibits viral replication | Chronic HCV, increase duration of therapy needed for genotype 3 of HCV | Fatigue, headache, severe bradycardia with amiodarone or beta blockers |
| Velpatasavir | Inhibitor of NS5A protein; viral replication complex inhibitor | Chronic HCV | Headache, fatigue |
| Ledipasvir | Inhibitor of viral HCV NS5A, that plays a role in viral replication, assembly and release | Chronic HCV | Fatigue, headache; Caution when prescribed with cyt P450 inducers as it decreases drug levels causing treatment failure |
| Grazoprevir | HCV protease inhibitor, inhibits viral replication | Chronic HCV | Hepatotoxicity, diarrhea, headache |
Sign up for free to take 1 quiz question on this topic