McKenna's Pharmacology for Nursing, 2e

127

C H A P T E R 1 0  Antiviral agents

AGENTS FOR INFLUENZA A AND RESPIRATORY VIRUSES

AGENTS FOR HIV AND AIDS Non-nucleoside reverse transcriptase inhibitors efavirenz etravirine nevirapine rilpivirine Nucleoside reverse transcriptase inhibitors abacavir didanosine emtricitabine lamivudine

Protease inhibitors atazanavir darunavir fosamprenavir

Integrase inhibitor raltegravir

amantadine oseltamivir ribavirin zanamivir

ANTIHEPATITIS B AGENTS adefovir entecavir telbivudine ANTIHEPATITIS C AGENTS bocepevir telaprevir

indinavir lopinavir ritonavir

AGENTS FOR HERPES VIRUS AND CYTOMEGALOVIRUS

saquinavir telaprevir tipranavir Fusion Inhibitor enfuvirtide CCR5 coreceptor antagonist maraviroc

aciclovir cidofovir famciclovir foscarnet

LOCALLY ACTIVE ANTIVIRAL AGENTS

ganciclovir valaciclovir valganciclovir

ganciclovir imiquimod

stavudine tenofovir zidovudine

V iruses cause a variety of conditions, ranging from warts, to the common cold and “flu”, to diseases such as chickenpox and measles. A single virus particle is composed of a piece of DNA or RNA inside a protein coat. To carry on any metabolic processes, including replication, a virus must enter a cell. Once a virus has fused with a cell wall and injected its DNA or RNA into the host cell, that cell is altered—that is, it is “pro- grammed” to control the metabolic processes that the virus needs to survive. The virus, including the protein coat, replicates in the host cell (Figure 10.1). When the

host cell can no longer carry out its own metabolic func- tions because of the viral invader, the host cell dies and releases the new viruses into the body to invade other cells. Because viruses are contained inside human cells while they are in the body, researchers have difficulty developing effective drugs that destroy a virus without harming the human host. Interferons (see Chapter 15) are released by the host in response to viral invasion of a cell and act to prevent the replication of that particular virus. Some interferons that affect particular viruses can

Nucleus

DNA or RNA

Capsid

A

B

C

Virus enters by pinocytosis

Virus sheds coat

Virus adheres to cell surface

Release G

F

E

D

Assembly of new virions

Synthesis of viral protein of capsid

Replication of viral nucleic acids

FIGURE 10.1  The stages in the replication cycle of a virus.