Iv%25252525252525252525252525252525252525252525252520gentamicin

# IV Gentamicin ## Overview Gentamicin is an aminoglycoside antibiotic that exerts bactericidal activity by binding to the 30S ribosomal subunit, inhibiting protein synthesis. It demonstrates concentration-dependent killing and has a significant post-antibiotic effect. ## Primary Indications Treatment of serious infections caused by susceptible aerobic gram-negative bacilli (e.g., *Pseudomonas aeruginosa*, *Enterobacteriaceae*), severe staphylococcal infections (often in combination with other agents), and synergistic therapy for infective endocarditis (streptococcal or enterococcal). ## Adult Dosing * **Traditional (Multiple Daily Dose):** 1–2.5 mg/kg IV every 8–12 hours. * **Extended-Interval (Once-Daily):** 5–7 mg/kg IV every 24 hours (dosing interval may be extended based on renal function/nomograms). * **Synergy (Endocarditis):** 1 mg/kg IV every 8 hours. * *Note: Dosing should always be based on Ideal Body Weight (IBW) if the patient is non-obese, or an adjusted body weight if obese.* ## Pediatric Dosing * **Neonates (Postnatal Age <7 days):** 2.5–4 mg/kg/dose every 18–24 hours. * **Neonates (Postnatal Age ≥7 days):** 2.5–3 mg/kg/dose every 12–18 hours. * **Infants/Children:** 2.5 mg/kg IV every 8 hours; higher doses (e.g., 5–7.5 mg/kg/dose) may be used for extended-interval protocols depending on institutional guidelines. ## Dose Adjustments * **Renal Impairment:** Mandatory. Utilize the Cockcroft-Gault equation for creatinine clearance (CrCl). If CrCl <60 mL/min, the dosing interval must be increased or the dose reduced. Avoid once-daily dosing in patients with CrCl <30 mL/min unless guided by specific institutional pharmacokinetic (PK) protocols. * **Hepatic Impairment:** No specific adjustment required; caution is advised due to potential hepatorenal syndrome. ## Contraindications * Hypersensitivity to gentamicin or other aminoglycosides. * Myasthenia gravis (may exacerbate muscle weakness). ## Adverse Effects * **Nephrotoxicity:** Usually reversible; manifests as rising serum creatinine. Risk is increased with prolonged therapy or concomitant nephrotoxins. * **Ototoxicity:** Often irreversible; involves vestibular (vertigo, ataxia) or auditory (tinnitus, high-frequency hearing loss) damage. * **Neuromuscular Blockade:** Rare but severe, especially in patients receiving neuromuscular blockers or anesthesia. ## Key Drug Interactions * **Nephrotoxic Agents:** Increased risk of renal injury (e.g., vancomycin, amphotericin B, cisplatin, NSAIDs, cyclosporine). * **Ototoxic Agents:** Increased risk of auditory/vestibular damage (e.g., loop diuretics such as furosemide). * **Neuromuscular Blockers:** Potential for prolonged paralysis or respiratory depression. ## Monitoring * **Serum Concentrations:** * **Trough:** Draw 30 minutes prior to the next dose (goal <1–2 mcg/mL for traditional dosing). * **Peak:** Draw 30 minutes after completion of a 30-minute infusion (goal 5–10 mcg/mL for traditional dosing). * **Renal Function:** Serum creatinine and urine output daily. * **Hearing/Balance:** Monitor for symptoms of ototoxicity. ## Clinical Pearls * Gentamicin follows linear PK; adjustments should be calculated using the Hartford Nomogram or similar institutional PK software for extended-interval dosing. * Avoid gentamicin in patients with preexisting renal failure unless absolutely necessary, as it is primarily renally cleared. * Always ensure adequate hydration to minimize nephrotoxicity risk. *** **Educational Disclaimer:** This information is for educational purposes only. Clinical practice varies by institution; always verify current prescribing information, institutional protocols, and specific patient safety parameters with your pharmacist or local clinical guidelines before administering medication.