Iv%2525252525252525252525252525252525252520gentamicin

# IV Gentamicin ## Overview Gentamicin is an aminoglycoside antibiotic that exerts bactericidal activity by binding to the 30S ribosomal subunit, inhibiting protein synthesis. It possesses a narrow therapeutic index and exhibits concentration-dependent killing and a significant post-antibiotic effect. ## Primary Indications Treatment of serious infections caused by susceptible aerobic Gram-negative bacilli, including *Pseudomonas aeruginosa*, *Enterobacteriaceae*, and synergy with beta-lactams or vancomycin for Gram-positive organisms (e.g., *Enterococcus* or *Staphylococcus* endocarditis). ## Adult Dosing * **Conventional Dosing:** 1.5–2.5 mg/kg IV every 8–12 hours. * **Extended-Interval Dosing (EID):** 5–7 mg/kg IV every 24 hours (preferred for many infections to reduce toxicity). * **Synergy Dosing (Endocarditis):** 1 mg/kg IV every 8 hours. * *Note: Dosing must be based on actual body weight; adjust for patients with obesity (typically using adjusted body weight).* ## Pediatric Dosing * **Neonates (0–4 weeks):** Dosing is highly dependent on postmenstrual age (PMA) and weight; typically 3–5 mg/kg/dose at intervals ranging from every 24 to 48 hours. * **Infants/Children (1 month–17 years):** 2.5 mg/kg IV every 8 hours (conventional) or 7 mg/kg IV every 24 hours (EID). * *Consult institutional protocols or the Harriet Lane Handbook for exact neonate dosing.* ## Dose Adjustments * **Renal Impairment:** Reduce frequency or dose based on CrCl (Cockcroft-Gault). For patients on dialysis, dosing must occur post-hemodialysis. * **Obesity:** Use adjusted body weight (IBW + 0.4 * [Actual Weight - IBW]) to prevent overdosage. ## Contraindications * Hypersensitivity to aminoglycosides. * Myasthenia gravis (may exacerbate muscle weakness). ## Adverse Effects * **Nephrotoxicity:** Usually reversible; associated with prolonged trough levels. * **Ototoxicity:** Irreversible (vestibular and auditory); associated with high peak levels and prolonged duration. * **Neuromuscular Blockade:** Rare, but can cause respiratory paralysis. ## Key Drug Interactions * **Nephrotoxic Agents:** Avoid concurrent use with amphotericin B, vancomycin, cisplatin, cyclosporine, or NSAIDs. * **Loop Diuretics:** Increase risk of ototoxicity (e.g., furosemide). * **Neuromuscular Blocking Agents:** May enhance or prolong neuromuscular blockade. ## Monitoring * **Renal Function:** Monitor baseline and serial SCr and BUN. * **Serum Concentrations:** * **Conventional:** Draw trough 30 minutes before 3rd or 4th dose; draw peak 30 minutes after completion of 30-minute infusion. * **EID:** Use a standard nomogram (e.g., Hartford Nomogram). Draw a random level 6–14 hours post-dose. * **Auditory/Vestibular:** Monitor for hearing loss, tinnitus, or vertigo. ## Clinical Pearls * **Peak/Trough Targets:** Conventional troughs should be <1–2 mcg/mL. * **Hydration:** Ensure adequate patient hydration to minimize renal accumulation. * **Administration:** Infuse over 30–60 minutes. Do not mix with penicillins in the same IV line, as they can cause chemical inactivation. * **Local Protocols:** Significant variation exists between institutions regarding EID versus conventional dosing and specific nomogram use; always defer to your facility’s infectious disease or pharmacy guidelines. *** *Disclaimer: This information is for educational purposes and does not substitute for professional clinical judgment. Dosing and monitoring protocols vary widely by institution and patient-specific factors. Always verify current prescribing information, institutional guidelines, and manufacturer labels before administering medication.*