Anti-infective drugs

Anti-infective drugs

Just the facts

In this chapter, you’ll learn:

• classes of drugs that act as anti-infectives
• the uses and varying actions of these drugs
• how these drugs are absorbed, distributed, metabolized, and excreted
• drug interactions and adverse reactions to these drugs.

Selecting an antimicrobial drug

Selecting an appropriate antimicrobial drug to treat a specific infection involves several important factors:

• First, the microorganism must be isolated and identified’generally through growing a culture.
• Then its susceptibility to various drugs must be determined. Because culture and sensitivity results take 48 hours, treatment usually starts at assessment and then is reevaluated when test results are obtained.
• The location of the infection must be considered. For therapy to be effective, an adequate concentration of the antimicrobial must be delivered to the infection site.
• Lastly, the cost of the drug must be considered as well as its potential adverse effects and the possibility of patient allergies.

Preventing pathogen resistance

The usefulness of antimicrobial drugs is limited by pathogens that may develop resistance to a drug’s action.

Resistance is the ability of a microorganism to live and grow in the presence of an antimicrobial drug that’s either bacteriostatic (inhibits the growth or multiplication of bacteria) or bactericidal
(kills bacteria). Resistance usually results from genetic mutation of the microorganism.