Chapter 28: Tetracyclines, Aminoglycosides & Fluoroquinolones

Tetracyclines, Aminoglycosides & Fluoroquinolones highlights their effectiveness in treating acne vulgaris, Helicobacter pylori, and rickettsial infections, while emphasizing critical drug-food interactions where absorption is significantly reduced by dairy products, iron, and antacids containing magnesium or aluminum. The text underscores major contraindications, specifically prohibiting use in pregnancy and children under eight due to risks of teratogenic effects and permanent tooth discoloration. The chapter then introduces glycylcyclines, represented by tigecycline, a synthetic analogue designed to overcome resistance in pathogens like methicillin-resistant Staphylococcus aureus (MRSA) and administered exclusively via intravenous routes. A significant portion of the summary focuses on aminoglycosides, including gentamicin and tobramycin, which are potent bactericidal agents used primarily against serious gram-negative infections such as Pseudomonas aeruginosa. The text stresses the critical importance of therapeutic drug monitoring (TDM) to measure peak and trough levels, ensuring efficacy while minimizing severe adverse effects like ototoxicity (hearing and balance loss) and nephrotoxicity (kidney damage). Finally, the chapter examines fluoroquinolones, such as ciprofloxacin and levofloxacin, which interfere with the enzyme DNA gyrase to prevent bacterial DNA synthesis. This section reviews their use in urinary, respiratory, and skin infections, alongside stern warnings regarding potential tendon rupture, crystalluria, and photosensitivity, necessitating patient education on proper hydration and sun protection.