Pharmacology of Aminoglycosides

What is the primary mechanism of absorption for aminoglycosides?

What is the primary mode of elimination for aminoglycosides?

What is the percentage incidence of nephrotoxicity associated with aminoglycosides?

What is the effect of concurrent administration of aminoglycosides with neuromuscular blockers?

What is the primary mechanism of antibacterial effect of aminoglycosides?

What is the effect of aminoglycosides on myasthenia gravis patients?

What is the mechanism of action of quinolone antibiotics?

Which of the following antibiotics is an antimetabolite?

What is the clinical use of sulfonamide antibiotics?

Which of the following antibiotics is often used in combination with penicillin G or ampicillin to treat enterococcal infections?

How is vancomycin eliminated from the body?

What is a common side effect of vancomycin?

Which of the following penicillins is sensitive to beta-lactamase and has a narrow spectrum?

What is the primary mechanism of elimination for most penicillins?

Which of the following bacteria is NOT typically covered by the spectrum of ampicillin?

What is the primary purpose of beta-lactamase inhibitors?

What is the most common side effect of penicillin therapy?

Which of the following penicillins undergoes enterohepatic cycling?

What is the primary characteristic of benzathine penicillin G?

Which of the following statements is TRUE about the spectrum of ticarcillin?

Spectrum: MRSA, Enterococci, Clostridium difficile (backup drug)
Resistance: Vancomycin-resistant staphylococcal (VRSA) and enterococcal (VRE) strains
Pharmacokinetics: used IV and orally (not absorbed) in colitis, enters most tissues, eliminated by renal filtration
Side effects: "Red man syndrome" (histamine release), ototoxicity (permanent, additive with other drugs), nephrotoxicity (mild, additive with other drugs)

Mechanism of action: inhibition of protein synthesis
Spectrum: gram-negative rods; gentamicin, tobramycin, and amikacin often used in combinations
Pharmacokinetics: polar compounds, not absorbed orally, widely distributed into tissues, renal elimination proportional to GFR
Side effects: nephrotoxicity (6-7% incidence), ototoxicity (2% incidence), neuromuscular paralysis

Subgroups:
- Narrow spectrum, beta-lactamase sensitive: penicillin G and penicillin V (spectrum: streptococci, pneumococci, meningococci, Treponema pallidum)
- Very narrow spectrum, beta-lactamase resistant: nafcillin, methicillin, oxacillin (spectrum: known or suspected staphylococci, not MRSA)
- Broad spectrum, beta-lactamase sensitive: ampicillin and amoxicillin (spectrum: gram-positive cocci, E. coli, H. influenzae, Listeria monocytogenes, Borrelia burgdorferi, H. pylori)
- Extended spectrum, antipseudomonal, beta-lactamase sensitive: ticarcillin, piperacillin (spectrum: increased activity against gram-negative rods, including P. aeruginosa)
Pharmacokinetics: most eliminated via active tubular secretion, dose reduction needed only in major renal dysfunction
Side effects: hypersensitivity (5-7% incidence), GI distress, Jarisch-Herxheimer reaction in treatment of syphilis