Please check your internet connection and try again.
# IV Gentamicin
## Overview
Gentamicin is an aminoglycoside antibiotic that exerts bactericidal activity by inhibiting bacterial protein synthesis via irreversible binding to the 30S ribosomal subunit. It exhibits concentration-dependent killing and a significant post-antibiotic effect.
## Primary Indications
Treatment of serious infections caused by susceptible Gram-negative bacteria (e.g., *Pseudomonas aeruginosa*, *Enterobacter*, *Klebsiella*), synergy for Gram-positive endocarditis (e.g., *Enterococcus*, *Staphylococcus*), and empirical treatment of neonatal sepsis.
## Adult Dosing
Standard dosing is highly protocol-dependent (e.g., extended-interval vs. traditional dosing).
* **Traditional (Extended-Interval):** 5–7 mg/kg IV every 24 hours (adjusted based on renal function and serum levels).
* **Synergy (Gram-positive):** 1 mg/kg IV every 8 hours.
* **Maximum:** Dosing must be individualized via pharmacokinetics. Always verify local institutional protocols for nomograms (e.g., Hartford nomogram).
## Pediatric Dosing
* **Neonates (Post-menstrual age dependent):** Typically 4–5 mg/kg IV every 24–48 hours; dosing intervals widen with decreasing gestational age.
* **Infants/Children:** 7.5 mg/kg/day total divided every 8 hours (traditional) or 5–7.5 mg/kg IV once daily (extended-interval).
* *Note: Always consult pediatric drug references (e.g., Harriet Lane) or local protocols due to maturity-dependent clearance.*
## Dose Adjustments
* **Renal Impairment:** Mandatory dose and/or interval adjustments based on CrCl or GFR. Avoid if possible in severe dysfunction.
* **Obesity:** Use adjusted body weight for dosing calculations in adults to avoid toxicity.
## Contraindications
* Hypersensitivity to gentamicin or other aminoglycosides.
* History of severe neuromuscular disorders (e.g., myasthenia gravis) as clinical status may be worsened.
## Adverse Effects
* **Nephrotoxicity:** Usually reversible; manifests as rising serum creatinine.
* **Ototoxicity:** Vestibular (vertigo, ataxia) or auditory (tinnitus, high-frequency hearing loss); may be irreversible.
* **Neuromuscular blockade:** Rare; associated with rapid infusion or high systemic levels.
## Key Drug Interactions
* **Nephrotoxic agents:** Increased risk of renal injury (e.g., vancomycin, amphotericin B, IV contrast, NSAIDs, loop diuretics).
* **Ototoxic agents:** Increased risk of permanent hearing loss (e.g., furosemide, cisplatin).
* **Neuromuscular blockers:** Potentiation of paralytic effects.
## Monitoring
* **Serum Levels:** Monitor trough levels (pre-dose) and/or peak levels depending on the dosing strategy. Troughs should generally be <1–2 mcg/mL (traditional) to minimize toxicity.
* **Renal Function:** Serum creatinine and urine output.
* **Signs of Toxicity:** Monitor for vestibular dysfunction (dizziness) and audiological changes.
## Clinical Pearls
* **Hydration:** Ensure adequate patient hydration to reduce the risk of acute tubular necrosis.
* **Infusion Time:** Administer IV doses over at least 30 minutes to reduce the risk of neuromuscular blockade.
* **Site Stability:** Physically incompatible with beta-lactams in the same IV line; flush lines thoroughly between doses.
* **Local Policy:** Dosing and monitoring protocols vary widely by institution. Always adhere to your facility’s specific pharmacokinetic dosing guidelines.
***
*Disclaimer: This information is for educational purposes only. Clinical guidelines, local resistance patterns, and institutional protocols evolve frequently. Always verify specific doses, contraindications, and drug compatibility through your current institutional formulary or official prescribing information (e.g., Lexicomp, Micromedex) before administration.*
