Please check your internet connection and try again.
# IV Gentamicin
## Overview
Gentamicin is an aminoglycoside antibiotic that exerts bactericidal activity by binding to the 30S ribosomal subunit, inhibiting bacterial protein synthesis. It provides rapid concentration-dependent killing, primarily against aerobic Gram-negative bacilli.
## Primary Indications
* Serious Gram-negative infections (e.g., *Pseudomonas aeruginosa*, *Enterobacteriaceae*).
* Synergistic treatment for Gram-positive endocarditis (e.g., *Staphylococcus* or *Enterococcus* species).
* Empiric treatment for suspected neonatal sepsis or febrile neutropenia (in combination regimens).
## Adult Dosing
* **Traditional Dosing (TID):** 1–2.5 mg/kg IV every 8 hours.
* **Extended-Interval (Once-Daily) Dosing:** 5–7 mg/kg IV every 24 hours (use caution in patients with impaired renal function or malignancy).
* **Synergy for Endocarditis:** 1 mg/kg IV every 8 hours (use in combination with a cell-wall active agent).
* *Note: Dosing must be based on ideal body weight (IBW) if the patient is obese; use adjusted body weight if total body weight >20% over IBW.*
## Pediatric Dosing
* **Neonates (0–28 days):** Dosing is highly weight and gestational age-dependent (e.g., 3–5 mg/kg/dose). Frequency ranges from every 18 to 48 hours. **Always consult specific neonatal nomograms.**
* **Infants/Children (>1 month):** 2.5 mg/kg IV every 8 hours (traditional). Extended-interval regimens (e.g., 7.5 mg/kg/dose) are increasingly common; consult institutional protocols.
## Dose Adjustments
* **Renal Impairment:** Reduce frequency or dose based on CrCl or GFR. Nephrotoxic risk requires individualization.
* **Hepatic Impairment:** No standard adjustment required, but use with caution in patients with hepatorenal syndrome.
## Contraindications
* Known hypersensitivity to gentamicin or any aminoglycoside.
* Use with extreme caution in patients with myasthenia gravis, parkinsonism, or those receiving neuromuscular blockers (risk of respiratory paralysis).
## Adverse Effects
* **Nephrotoxicity:** Usually reversible; associated with trough accumulation.
* **Ototoxicity:** Vestibular or auditory (often irreversible); related to prolonged duration of therapy or high trough levels.
* **Neuromuscular Blockade:** Rare, but can cause respiratory failure.
## Key Drug Interactions
* **Nephrotoxic agents:** Increased risk of renal injury (e.g., vancomycin, amphotericin B, cisplatin, NSAIDs).
* **Ototoxic agents:** Increased risk of hearing loss (e.g., loop diuretics such as furosemide).
* **Neuromuscular blockers:** Potentiation of blockade.
## Monitoring
* **Therapeutic Drug Monitoring (TDM):** Draw levels based on institutional protocols.
* *Traditional:* Trough levels (30 mins before 3rd or 4th dose) and Peak levels (30 mins after infusion completion).
* *Extended-Interval:* Random level (often 6–14 hours post-dose) plotted on a Hartford Nomogram.
* **Renal function:** Monitor serum creatinine and urine output daily.
* **Auditory/Vestibular:** Monitor for tinnitus, dizziness, or vertigo.
## Clinical Pearls
* Gentamicin lacks activity against anaerobes and generally has poor activity against atypical pathogens.
* Avoid prolonged therapy (>7–10 days) unless absolutely necessary to minimize toxicity.
* Ensure adequate hydration to reduce the risk of nephrotoxicity.
* Local protocols for dosing and monitoring vary widely; always prioritize institutional guidelines.
***
**Educational Disclaimer:** This information is for educational purposes only. Clinical practice and therapeutic guidelines change frequently. Always verify specific dosing, safety profiles, and institutional protocols with current prescribing information, drug databases (e.g., Lexicomp, Micromedex), or a clinical pharmacist before administration.
