Antiinfectives (1 & 2) Enhancement Reviewer PDF

PROPERTY BY: NCM 106 PHARMACOLOGY TEAM Overview of Microorganisms Types of Pathogens: Bacteria, Viruses, Protozoa, and Fungi. Their pathogenicity depends on their virulence. Bacteria: Prokaryotes (lack a true nucleus and nuclear membrane). ○ Shapes: Bacillus (rod-shap...

PROPERTY BY: NCM 106 PHARMACOLOGY TEAM Overview of Microorganisms Types of Pathogens: Bacteria, Viruses, Protozoa, and Fungi. Their pathogenicity depends on their virulence. Bacteria: Prokaryotes (lack a true nucleus and nuclear membrane). ○ Shapes: Bacillus (rod-shaped), Cocci (spherical); may form clusters (staphylococci) or chains (streptococci). ○ Classification by Staining: Gram-positive: Retain purple stain. Gram-negative: Do not retain stain; often more resistant to drugs. ○ Toxin Production: Some bacteria produce toxins, such as beta-lactamase, which promotes cell lysis. Mechanisms of Antibacterial Action Cell Wall Synthesis Inhibition: Disrupts cell structure, leading to cell death. Membrane Permeability Alteration: Compromises cell integrity. Protein Synthesis Inhibition: Prevents the formation of essential proteins. RNA and DNA Synthesis Inhibition: Disrupts genetic material, halting reproduction. Metabolism Interference: Alters cellular processes critical for survival. Types of Antibacterial Drugs Narrow-spectrum: Target specific pathogens. Broad-spectrum: Effective against a wide range of Gram-positive and Gram-negative bacteria. Drug Resistance NCM 106 TEAM Inherent Resistance: Natural immunity to certain drugs. Acquired Resistance: Developed through exposure to antibiotics. Hospital-acquired Infections: Often involve drug-resistant bacteria. Cross-resistance: Resistance to drugs with similar mechanisms. Antibiotic Combinations: ○ Additive: Combined effect equals the sum of individual effects. ○ Potentiative: One drug enhances the effect of the other. ○ Antagonistic: Drugs work against each other. Classes of Antibacterial Drugs and Key Agents Penicillins ○ Mechanism: Interfere with cell wall synthesis, bacteriostatic or bactericidal. ○ Common Types: Penicillin G: First penicillin, painful injectionG, short-acting. Penicillin V: Effective for mild infections. Broad-spectrum: Amoxicillin and Ampicillin, active against various Gram-negative organisms. Penicillinase-resistant: Dicloxacillin, Nafcillin, Oxacillin; effective against penicillinase-producing S. aureus. ○ Extended-Spectrum Penicillins: Effective against Pseudomonas aeruginosa and Gram-negative bacteria. ○ Adverse Effects: Allergic reactions, superinfections, organ toxicity. Beta-Lactamase Inhibitors ○ Action: Combine with penicillins (e.g., Amoxicillin-Clavulanic Acid) to inhibit bacterial enzymes, extending the antibacterial effect. ○ Examples: Clavulanic acid, Sulbactam, Tazobactam. PROPERTY BY: NCM 106 PHARMACOLOGY TEAM Cephalosporins (e.g., Ceftriaxone) ○ Mechanism: Cell wall synthesis inhibition, bactericidal. ○ Generations: Expanded activity across different Gram-negative bacteria as the generations progress. ○ Side Effects: GI disturbances, rash, headache; serious reactions include anaphylaxis, nephrotoxicity. Macrolides ○ Mechanism: Bind to ribosomes, inhibiting protein synthesis; bacteriostatic or bactericidal. ○ Examples: Erythromycin: Used for respiratory infections. Azithromycin: Broad use in respiratory and skin infections. ○ Adverse Reactions: GI disturbances, photosensitivity, hepatotoxicity; potential drug interactions with theophylline, carbamazepine, and warfarin. Extended Macrolide Group ○ Mechanism: they also inhibit protein synthesis, have a longer half-life and are administered once a day. ○ Example: clarithromycin Lincosamides (e.g., Clindamycin) ○ Action: Inhibits protein synthesis; effective against Gram-positive bacteria. ○ Adverse Reactions: GI disturbances, colitis, anaphylaxis. Glycopeptides (e.g., Vancomycin) ○ Mechanism: Inhibits cell wall synthesis; effective against drug-resistant Gram-positive bacteria. ○ Uses: MRSA infections, surgical prophylaxis for penicillin-allergic patients. ○ Adverse Reactions: Nephrotoxicity, ototoxicity, “red man syndrome” with rapid IV administration. NCM 106 TEAM Oxazolidinones ○ Mechanism: inhibit protein synthesis on the 50S ribosomal subunit of bacteria. This action prevents formation of 70s initiation complex, which is necessary for bacterial reproduction. ○ Example: Linezolid for Nosocomial pneumonia ○ tedizolid Ketolides (e.g., Telithromycin) ○ Use: Treats community-acquired pneumonia. ○ Adverse Reactions: Visual disturbances, liver failure, exacerbation of Myasthenia Gravis. Lipopeptides (e.g., Daptomycin) ○ Mechanism: Causes bacterial cell death; used for complex skin infections and septicemia. ○ Adverse Reactions: Increased bleeding risk, rhabdomyolysis. Tetracyclines (e.g., doxycycline) ○ Mechanism: Inhibits protein synthesis, broad-spectrum. ○ Uses: Respiratory infections, acne, STIs; avoid in pregnant women. ○ Side Effects: Photosensitivity, GI disturbances, tooth discoloration in children. Aminoglycosides (e.g., Gentamicin) ○ Mechanism: Protein synthesis inhibition; bactericidal, effective for serious infections. ○ Uses: Sepsis, meningitis, endocarditis. ○ Adverse Reactions: Ototoxicity, nephrotoxicity; careful monitoring of blood levels needed. Fluoroquinolones (e.g., Ciprofloxacin, Levofloxacin) ○ Mechanism: Inhibits DNA synthesis, effective against Gram-negative organisms. ○ Uses: UTIs, respiratory, skin infections. ○ Cautions: May cause CNS effects if given with NSAIDS, avoid antacids since it decreases absorption. Sulfonamides ○ Mechanism: Inhibits folic acid synthesis; bacteriostatic. ○ Uses: UTIs, ulcerative colitis ○ Adverse Reactions: Allergic reactions, photosensitivity, GI disturbances. Nitroimidazoles (e.g., Metronidazole) ○ Mechanism: Disrupts DNA synthesis in anaerobic bacteria and protozoa. ○ Uses: Anaerobic infections, C. difficile colitis, surgical prophylaxis. ○ Side Effects: Nausea, dizziness, metallic taste; disulfiram-like reaction with alcohol. PROPERTY BY: NCM 106 PHARMACOLOGY TEAM Patient Education and Nursing Considerations Compliance: Emphasize the importance of completing the entire course of antibiotics to prevent resistance. Fluid Intake: Advise increased fluids to prevent crystalluria (especially with sulfonamides and fluoroquinolones). Photosensitivity: Use sunscreen and avoid direct sunlight, especially with tetracyclines and sulfonamides. Drug Interactions: ○ Avoid combining with antacids (tetracyclines, fluoroquinolones). ○ Be cautious with oral contraceptives (reduced effectiveness with certain antibiotics). ○ Avoid alcohol with metronidazole (disulfiram reaction). Monitor for Side Effects: Report signs of superinfection (e.g., mouth ulcers), allergic reactions, and adverse effects (e.g., hearing loss with aminoglycosides). Administration Tips: ○ Take with food if GI upset occurs (unless contraindicated). ○ Chewable forms must be chewed thoroughly. ○ Store medications out of reach of children. NCM 106 TEAM