Summary ANTIMICROBIALS AND ANTI-INFECTIVE PHARMACOTHERAPY

ANTIMICROBIALS AND ANTI-INFECTIVE PHARMACOTHERAPY



Classification and Actions of Anti-Infective Drugs

Mechanisms of Anti-Infective Drugs

 Anti-infective drugs affect the target organism's structure, metabolism, or life cycle.

 Antibiotics are natural substances produced by bacteria to kill other bacteria.

 Bactericidal agents kill bacteria, while bacteriostatic agents slow their growth.

Selection of Effective Antibiotics

 Culture and Sensitivity (C & S) Testing involves examining specimens for
microorganisms, identifying them, and testing their sensitivity to different antibiotics.

 Broad-spectrum antibiotics may be initiated before lab culture completion.

 Superinfections are secondary infections that occur when host flora are excessively killed
by antibiotics.

Antibacterial Drugs

 Classes of antibiotics include Penicillin, Cephalosporins, Tetracyclines, Macrolides,
Aminoglycosides, Fluoroquinolones, and Sulfonamides.

 Penicillins work by disrupting bacterial cell walls, most effective against gram-positive
bacteria.

 Examples of penicillins include Penicillin G, which is administered intravenously or
intramuscularly.

Pharmacotherapy with Penicillins

Mechanism of Action

 Penicillins kill bacteria by disrupting their cell walls, allowing water to enter.

 They are most effective against gram-positive bacteria.

, Prototype Drug: Penicillin G

 Therapeutic Class: Antibacterial

 Pharmacologic Class: Cell wall inhibitor; natural penicillin

 Uses: Effective against Streptococci, Pneumococci, and Staphylococci.

Administration and Adverse Effects

 Only 15–30% of an oral dose of Penicillin G is absorbed.

 Adverse effects include anaphylaxis, diarrhea, nausea, and vomiting.

Pharmacotherapy with Cephalosporins

Mechanism of Action

 Cephalosporins bind to bacterial cell walls, inhibiting cell-wall synthesis.

 They have broad-spectrum activity against gram-negative organisms.

Prototype Drug: Cefazolin (Ancef, Kefzol)

 Therapeutic Class: Antibacterial

 Pharmacologic Class: First-generation cephalosporin

 Actions and Uses: Commonly used for respiratory, urinary, bone, and joint infections.

Administration and Adverse Effects

 Administer IM injections deep into a large muscle mass to prevent tissue injury.

 Adverse effects may include rash and diarrhea, with a lower likelihood of allergic
reactions.

Pharmacotherapy with Tetracyclines

Actions and Uses

 Tetracyclines inhibit protein synthesis and are effective against a broad spectrum of
bacteria.