3.14 Antivirals
Unlike the complex structure of fungi or protozoa, viral structure is simple. There are several subclasses of antiviral medications: antiherpes, antiinfluenza, antihepatitis, and antiretrovirals. Each subclass will be discussed in more detail below. See Figure 3.8[1] for images of viruses.
Subclass: Antiherpes
Mechanism of Action: Acyclovir causes termination of the DNA chain during the viral replication process. Acyclovir can be administered either topically or systemically, depending on the infection.[2]
Indications: Acyclovir (Zovirax) and its derivatives are frequently used for the treatment and prevention of herpes and varicella virus infections, including genital herpes, chicken pox, shingles, Epstein-Barr virus infections, and cytomegalovirus infections.
Nursing Considerations: Acyclovir use may result in nephrotoxicity.
Side Effects/Adverse Effects: Common side effects may include gastrointestinal distress. Additional adverse effects may include renal impairment and decreased seizure threshold.
Health Teaching & Health Promotion: Clients who are being treated with antiviral therapy should be instructed about the importance of medication compliance. They may also experience significant fatigue, so periods of rest should be encouraged.[3]
Subclass: Antiinfluenza
Mechanism of Action: Tamiflu prevents the release of virus from infected cells.
The influenza virus is one of the few RNA viruses that replicates in the nucleus of cells. Antivirals block the release stage. See Figure 3.9.[4]
Indications: Oseltamivir (Tamiflu) is used to target the influenza virus by blocking the release of the virus from the infected cells.
Nursing Considerations: This medication does not cure influenza but can decrease flu symptoms and shorten the duration of illness if taken within 48 hours of symptom onset. Clients are prescribed the medication for prophylaxis against infection, known exposure, or to lessen the course of the illness. If clients experience flu-like symptoms, it is critical that they start treatment within 48 hours of symptom onset.
Side Effects/Adverse Effects: Common side effects include GI upset. Adverse effects include serious skin hypersensitivity reactions or neuropsychiatric symptoms, especially in children. Use cautiously in clients with renal failure, chronic cardiac or respiratory diseases, or any medical condition that may require imminent hospitalization.
Health Teaching & Health Promotion: Clients who are being treated with antiviral therapy should be instructed about the importance of medication compliance. They may also experience significant fatigue, so periods of rest should be encouraged.[5]
Subclass: Antihepatitis
Mechanism of Action: Antihepatitis medications inhibit translation of viral mRNA into viral proteins. This action impedes the replication of the hepatitis virus.
Indications: Antihepatits medications like adefovir are used to treat chronic hepatitis and the hepatitis B virus and hepatitis C virus.
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