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Gentamicin (Systemic)

Medically reviewed by Drugs.com. Last updated on Aug 12, 2019.

Pronunciation

(jen ta MYE sin)

Index Terms

  • Gentamicin Sulfate

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product

Solution, Injection:

Generic: 10 mg/mL (2 mL [DSC]); 40 mg/mL (2 mL, 20 mL)

Solution, Injection [preservative free]:

Generic: 10 mg/mL (2 mL)

Solution, Intravenous:

Generic: 60 mg (50 mL); 70 mg (50 mL [DSC]); 80 mg (50 mL, 100 mL); 90 mg (100 mL [DSC]); 100 mg (50 mL, 100 mL); 120 mg (100 mL); 10 mg/mL (6 mL [DSC], 10 mL [DSC])

Pharmacologic Category

  • Antibiotic, Aminoglycoside

Pharmacology

Interferes with bacterial protein synthesis by binding to 30S ribosomal subunit resulting in a defective bacterial cell membrane

Absorption

Intramuscular: Rapid and complete; Oral: Poorly absorbed (<1%) (MacDougall 2011)

Distribution

Primarily into extracellular fluid (highly hydrophilic); high concentration in the renal cortex; minimal penetration to CSF and ocular tissues via IV route

Vd: Higher in neonates than older pediatric patients; increased by edema, ascites, fluid overload; decreased with dehydration

Neonates: 0.45 ± 0.1 L/kg

Infants: 0.4 ± 0.1 L/kg

Children:0.35 ± 0.15 L/kg

Adolescents: 0.3 ± 0.1 L/kg

Adults: 0.2 to 0.3 L/kg (Leggett 2015)

CSF:blood level ratio: Normal meninges: <10%; Inflamed meninges: ≤25% (MacDougall 2011)

Excretion

Urine (>70% as unchanged drug)

Clearance: Directly related to renal function

Neonates: 0.045 ± 0.01 L/hour/kg

Infants: 0.1 ± 0.05 L/hour/kg

Children: 0.1 ± 0.03 L/hour/kg

Adolescents: 0.09 ± 0.03 L/hour/kg

Time to Peak

Serum: IM: 30 to 90 minutes; IV: 30 minutes after 30-minute infusion (MacDougall 2011); Note: Distribution may be prolonged after larger doses. One study reported a 1.7-hour distribution period after a 60-minute, high-dose aminoglycoside infusion (Demczar 1997).

Half-Life Elimination

Neonates: <1 week: 3 to 11.5 hours; 1 week to 1 month: 3 to 6 hours

Infants: 4 ± 1 hour

Children: 2 ± 1 hour

Adolescents: 1.5 ± 1 hour

Adults: ~2 hours (Regamey 1973); Renal failure: mean: 41 ± 24 hours; Range: 6 to 127 hours (Dager 2006)

Protein Binding

<30%

Special Populations: Renal Function Impairment

Clearance is decreased in renal impairment.

Use: Labeled Indications

Serious infections: Treatment of serious infections (eg, sepsis, meningitis, urinary tract infections, respiratory tract infections, peritonitis, bone infections, skin and soft tissue infections) caused by susceptible strains of the following microorganisms: Pseudomonas aeruginosa, Proteus species (indole-positive and indole-negative), Escherichia coli, Klebsiella species, Enterobacter species, Serratia species, Citrobacter species, and Staphylococcus species (coagulase-positive and coagulase-negative); treatment of infective endocarditis caused by enterococci, in combination with other antibiotics.

Off Label Uses

Bartonella spp. infections

Data from a limited number of patients studied suggest that gentamicin, in combination with doxycycline, may be beneficial for the treatment of bacteremia [Foucault 2003]. Clinical experience suggests the utility of gentamicin, in combination with rifampin, for the treatment of disseminated cat scratch disease [Spach 2019a].

Based on the US Department of Health and Human Services (HHS) guidelines for the prevention and treatment of opportunistic infections in adults and adolescents with HIV, gentamicin, in combination with doxycycline, is a recommended and effective treatment for infective endocarditis due to Bartonella in adolescent and adult HIV-infected patients.

Brucellosis

Data from a limited number of clinical trials suggest that gentamicin, in combination with doxycycline, may be beneficial for the treatment of brucellosis [Ariza 2007].

Endocarditis, treatment (viridans group streptococci and Streptococcus bovis [native or prosthetic valve]) (adults)

Based on the American Heart Association (AHA) scientific statement for infective endocarditis in adults, gentamicin, in combination with other antibiotics, is an effective and recommended treatment option for infective endocarditis due to viridans group streptococci (VGS) and S. bovis (native or prosthetic valve).

Gonococcal infection, uncomplicated (patients with severe cephalosporin allergy)

Based on the Centers for Disease Control and Prevention (CDC) sexually transmitted diseases treatment guidelines, gentamicin in combination with azithromycin may be considered in the treatment of uncomplicated gonococcal infection in patients with severe cephalosporin allergy.

Intra-amniotic infection

Based on the American College of Obstetricians and Gynecologists (ACOG) committee opinion on intrapartum management of intra-amniotic infection, gentamicin, in combination with ampicillin, is a recommended and effective agent for the treatment of intra-amniotic infection.

Pelvic inflammatory disease

Based on the CDC sexually transmitted diseases treatment guidelines, gentamicin in combination with clindamycin is an effective and recommended parenteral regimen for the treatment of pelvic inflammatory disease.

Peritonitis, treatment (peritoneal dialysis patients)

Based on the International Society for Peritoneal Dialysis (ISPD) guidelines for prevention and treatment of peritonitis, intraperitoneal gentamicin, in combination with other antibiotics, is effective and recommended for empiric treatment of peritoneal dialysis-associated peritonitis; as adjunctive therapy for severe enterococcal peritonitis; and as an option in combination therapy for Pseudomonas peritonitis.

Plague (Yersinia pestis), treatment

Data from a limited number of patients studied suggest that gentamicin may be beneficial for the treatment of plague (Yersinia pestis) [Boulanger 2004].

Postpartum endometritis

Data from two double-blind studies support the use of gentamicin (once-daily dosing), in combination with clindamycin, in the treatment of postpartum endometritis [Del Priore 1996], [Livingston 2003].

Surgical prophylaxis (alternative agent for select GI tract, GU tract, or gynecologic/obstetric procedures)

Based on the American Society of Health-System Pharmacists (ASHP), Infectious Diseases Society of America (IDSA), Surgical Infection Society (SIS), and Society of Healthcare Epidemiology of America (SHEA) guidelines for antimicrobial prophylaxis in surgery, gentamicin is an effective and recommended alternative agent (in combination with other antibiotics) for patients with beta-lactam allergy for a number of surgical procedures (eg, gastroduodenal, biliary tract, cesarean delivery, liver transplantation, or pancreas and pancreas-kidney transplantation) and may be used first-line in combination with cefazolin for procedures involving implantation of prosthetic material (eg, penile prosthesis).

Tularemia

Based on the World Health Organization guidelines on tularemia and the Working Group on Civilian Biodefense consensus-based recommendations for tularemia as a biological weapon [Dennis 2001], gentamicin is an effective and recommended agent for the treatment of severe tularemia or tularemia in a contained casualty setting.

Contraindications

Hypersensitivity to gentamicin, other aminoglycosides, or any component of the formulation

Dosing: Adult

Note: Aminoglycoside dosing weight: For underweight patients (ie, total body weight [TBW] < ideal body weight [IBW]), calculate the dose based on TBW. For nonobese patients (ie, TBW 1 to 1.25 × IBW), calculate the dose based on TBW or IBW. TBW may be preferred in nonobese patients who may have increased volume of distribution (eg, critically ill). For obese patients (ie, TBW >1.25 × IBW), calculate the dose based on 40% adjusted body weight (IBW + [0.4 × (TBW-IBW)]) (Bailey 1997; Blackburn 2015; Nicolau 1995; Rea 2008). Therapeutic drug monitoring: Monitoring of serum concentrations is recommended to ensure efficacy and avoid toxicity, particularly in critically ill patients with serious infections or in disease states known to significantly alter aminoglycoside pharmacokinetics (eg, cystic fibrosis, burns, major surgery). Timing and frequency of concentration monitoring is individualized based on dosing and monitoring strategy (Buijk 2002; Drew 2019; Nezic 2014).

Usual dosage range:

Gram-negative infections:

Conventional/traditional dosing: IV, IM: 3 to 5 mg/kg/day in divided doses every 8 hours (Zaske 1982; manufacturer's labeling). Some experts favor an initial loading dose of 2.5 to 3 mg/kg (Drew 2019). Target peak concentration depends on indication and site of infection; in general, adjust dose to achieve peak of 4 to 6 mcg/mL for urinary tract infections and 7 to 10 mcg/mL for serious infections (including life-threatening infections). Target trough concentrations should be <2 mcg/mL; ideal target <1 mcg/mL (Bertino 1994; Drew 2019; Matzke 1983).

High-dose extended-interval dosing (once-daily dosing): IV: 5 to 7 mg/kg once daily; method is generally not recommended in patients with ascites, burns covering >20% of the total body surface area, end-stage renal disease (eg, requiring hemodialysis), or pregnancy (except for intrapartum therapy for intra-amniotic infection) due to altered pharmacokinetics. Use with caution in patients with CrCl <40 mL/minute (Bailey 1997; Buijk 2002; Drew 2019; Hodiamont 2017; Nicolau 1995). Adjust gentamicin dose and interval to achieve an extrapolated peak concentration of ~15 to 20 mcg/mL and trough concentration ≤1 mcg/mL; ideal target <0.5 mcg/mL (Buijk 2002; Drew 2019; Leggett 2015; Nicolau 1995; Pagkalis 2011).

Synergy dosing for non-CNS gram-positive infections:

IV, IM: 3 mg/kg/day in 1 to 3 divided doses in combination with a gram-positive active agent (AHA [Baddour 2015]; Leggett 2015; Olaison 2002). When divided doses are used, adjust gentamicin dose to achieve peak concentration of 3 to 4 mcg/mL and trough concentration <1 mcg/mL (AHA [Baddour 2015]).

Indication-specific dosing:

Bartonella spp. infections (off-label use):

Bacteremia with or without endocarditis: IV: 3 mg/kg/day in 1 or 3 divided doses in combination with doxycycline for 2 weeks, followed by doxycycline monotherapy (Foucault 2003; Rolain 2004; Spach 2019b; Spach 2019c; Spach 2019d). Some experts do not suggest gentamicin as part of the regimen for patients with HIV and bacteremia without endocarditis (HHS [OI adult 2019]).

Cat scratch disease, disseminated (eg, hepatosplenic, prolonged systemic febrile illness) (alternative agent): IV: 2 mg/kg as a single loading dose, followed by 1.5 mg/kg every 8 hours in combination with rifampin for 10 to 14 days (Spach 2019a).

Note: In contrast to other gram-negative infections, target a gentamicin peak concentration of 3 to 4 mcg/mL and trough concentration of <1 mcg/mL when divided doses are used (Spach 2019b; Spach 2019d).

Bloodstream infection:

Adjunctive empiric therapy for patients with sepsis/septic shock and concern for resistant gram-negative bacteria (eg, immunosuppression, prevalent local resistance, recent antibiotic exposure): IV: 5 to 7 mg/kg once daily in combination with a second gram-negative active agent; once culture and susceptibility results are available, can generally discontinue and use a single agent with documented activity. Gentamicin should not be used as monotherapy (Gilbert 1998; Machuca 2017; Moehring 2019; Nicolau 1995; SCCM [Rhodes 2017]; Shields 2016).

Antibiotic lock technique (catheter-salvage strategy) (off-label use): Note: For infections caused by susceptible organisms when the catheter cannot be removed; use in addition to systemic antibiotics (Girand 2019; IDSA [Mermel 2009]).

Intracatheter: Prepare lock solution to final concentration of gentamicin 1 to 5 mg/mL (may be combined with heparin) (Battistella 2010; Fortún 2006; IDSA [Mermel 2009]; Vercaigne 2002). The gentamicin concentration may vary by institution, catheter type, and whether heparin is utilized; solutions with heparin are preferred. Prepare solution immediately before instillation with a sufficient volume to fill the catheter (2 to 5 mL). Instill into each lumen of the catheter access port with a dwell time of up to 72 hours, depending on frequency of catheter use. Withdraw lock solution prior to catheter use; replace with fresh gentamicin lock solution after catheter use. Antibiotic lock therapy is given for the same duration as systemic antibiotics (Girand 2019; IDSA [Mermel 2009]; Krishnasami 2002).

Brucellosis (alternative agent) (off-label use): IV, IM: 5 mg/kg once daily in combination with doxycycline. Note: Duration depends on extent of disease; gentamicin is usually given for the first 5 to 14 days of therapy, followed by doxycycline monotherapy (Ariza 2007; Hasanjani Roushan 2006; Skalsky 2008). Additional agents or other regimens are preferred for neurobrucellosis, endocarditis, and infection in pregnant women (Bosilkovski 2019).

CNS infection, health care-associated (eg, cerebrospinal fluid [CSF] shunt infection) (adjunct to systemic therapy): Note: Reserved for infections due to multidrug-resistant organisms, infections refractory to appropriate parenteral therapy, or when infected shunts cannot be removed (Baddour 2019; Friedman 2019).

Intraventricular (use a preservative-free preparation): Initial: 4 to 8 mg/day; some experts recommend adjusting dosage and administration interval based on CSF gentamicin concentrations (goal: 10 to 20 times MIC of causative organism), ventricle size, and daily output from ventricular drain (IDSA [Tunkel 2017]). When intraventricular gentamicin is administered via a ventricular drain, clamp drain for 15 to 60 minutes after administration (allows solution to equilibrate in CSF). Duration is individualized according to clinical and microbiologic response (IDSA [Tunkel 2004]; IDSA [Tunkel 2017]).

Endocarditis, treatment:

Enterococcus spp. (native or prosthetic valve, without high-level gentamicin resistance): IV, IM: 1 mg/kg every 8 hours as part of an appropriate combination regimen. Duration is 4 to 6 weeks depending on duration of symptoms prior to presentation, source of infection, and the specific combination regimen (AHA [Baddour 2015]). Note: For native-valve endocarditis due to ampicillin-susceptible Enterococcus faecalis, some experts prefer a combination regimen that does not contain gentamicin (Sexton 2019a).

Staphylococcus spp. (prosthetic valve) (off-label use): IV, IM: 1 mg/kg every 8 hours for the first 2 weeks of an appropriate combination regimen; the other components should be continued for a total of ≥6 weeks (AHA [Baddour 2015]).

Viridans group streptococci and Streptococcus bovis (off-label use):

Native valve: Highly penicillin-susceptible (MIC ≤0.12 mcg/mL): IV, IM: 3 mg/kg/day once daily (preferred) or in 3 divided doses (alternative) in combination with a beta-lactam for 2 weeks. Note: This regimen is reserved for patients with uncomplicated infection, prompt response to therapy, and no preexisting renal failure (AHA [Baddour 2015]).

Native valve: Relatively penicillin-resistant (MIC >0.12 and <0.5 mcg/mL): IV, IM: 3 mg/kg/day once daily (preferred) or in 3 divided doses (alternative) in combination with a beta-lactam. Gentamicin duration is for the first 2 weeks of the total 4-week regimen (AHA [Baddour 2015]).

Native valve: Penicillin-resistant (MIC ≥0.5 mcg/mL): IV, IM: 3 mg/kg/day in 2 to 3 divided doses in combination with a beta-lactam. The duration of this regimen is not well established; infectious diseases consultation recommended (AHA [Baddour 2015]).

Prosthetic valve: Highly penicillin-susceptible (MIC ≤0.12 mcg/mL): IV, IM: 3 mg/kg/day once daily (preferred) or in 3 divided doses (alternative) in combination with a beta-lactam. Gentamicin duration is for the first 2 weeks of the total 6-week regimen (AHA [Baddour 2015]).

Prosthetic valve: Relatively penicillin-resistant (MIC >0.12 and <0.5 mcg/mL) or fully penicillin-resistant (MIC ≥0.5 mcg/mL): IV, IM: 3 mg/kg/day once daily or in 3 divided doses in combination with a beta-lactam for 6 weeks (AHA [Baddour 2015]); some experts prefer 3 divided doses for these isolates and also prefer shorter courses of the gentamicin component (≥2 weeks) for relatively penicillin-resistant strains (Karchmer 2019).

Meningitis, bacterial:

Enterococcus spp.: IV: 5 to 7 mg/kg/day in 1 or 3 divided doses (IDSA [Tunkel 2004]; Murray 2019); give as part of an appropriate combination regimen and individualize duration based on clinical response (IDSA [Tunkel 2004]; Murray 2019; Pintado 2003).

Listeria monocytogenes: IV: 5 mg/kg/day in 3 divided doses in combination with ampicillin or penicillin. Gentamicin is given until clinical improvement (typically ≥7 days) or in poor responders for up to 21 days, as long as there are no signs of nephrotoxicity or ototoxicity; total duration of antibiotic therapy is ≥21 days (Gelfand 2019; IDSA [Tunkel 2017]; Tunkel 2019).

Pelvic infections (off-label use): Note: Dose is based on actual body weight. For patients >1.2 × IBW, use 40% adjusted body weight (IBW + [0.4 × (TBW-IBW)]) (ACOG 2018).

Intra-amniotic infection (chorioamnionitis): IV: 5 mg/kg once daily (preferred) or 2 mg/kg loading dose followed by 1.5 mg/kg every 8 hours (alternative); give in combination with ampicillin. In women undergoing cesarean delivery, an anti-anaerobic agent should also be added. Continue regimen until vaginal delivery or for 1 dose after cesarean delivery (ACOG 2017; Locksmith 2005; Martingano 2019). Note: Some experts recommend 1 additional dose after vaginal delivery and extension of antibiotics after cesarean delivery until patient is afebrile and asymptomatic ≥48 hours (Tita 2019).

Postpartum endometritis: IV: 5 mg/kg once daily (preferred) or 1.5 mg/kg every 8 hours (alternative). Give in combination with clindamycin. Treat until the patient is clinically improved (no fundal tenderness) and afebrile for 24 to 48 hours (Chen 2019; Del Priore 1996; Livingston 2003; Mackeen 2015). Note: For women known to be colonized with group B Streptococcus, additional agents or other regimens are preferred (Chen 2019).

Peritonitis, treatment (peritoneal dialysis patients) (off-label use): As a component of empiric therapy or for pathogen-directed therapy. Note: Intraperitoneal administration is preferred to IV administration. Once culture results are available, switch to another active antibiotic class, if possible, to decrease the risk of toxicity; otherwise, duration of therapy is ≥3 weeks for patients with adequate clinical response (Burkart 2019; ISPD [Li 2016]).

Intermittent (strongly preferred): Intraperitoneal: 0.6 mg/kg added to one exchange of dialysis solution once daily (allow to dwell ≥6 hours) (ISPD [Li 2016]).

Continuous (with every exchange) (dose is per liter of dialysate): Intraperitoneal: Loading dose: 8 mg/L of dialysate with first exchange of dialysate; maintenance dose: 4 mg/L of dialysate with each subsequent exchange of dialysate (ISPD [Li 2016]).

Plague (Yersinia pestis), treatment (off-label use): IV, IM: 5 mg/kg once daily or 2 mg/kg loading dose, then 1.7 mg/kg every 8 hours; duration of therapy is 7 to 14 days and at least until 2 days after patient has defervesced (CDC 2015; Inglesby 2000; Sexton 2019b).

Sepsis or septic shock, adjunctive empiric gram-negative coverage (eg, in the setting of intra-abdominal infection, pneumonia, gram-negative bacteremia, or severe burn): Note: Some experts reserve for patients with immunocompromising conditions or risk for resistant gram-negative pathogens, in particular Pseudomonas aeruginosa (Moehring 2019; Schmidt 2019).

IV: 5 to 7 mg/kg once daily in combination with a second gram-negative agent (SCCM [Rhodes 2017]; Schmidt 2019); once culture and susceptibility tests are available, can generally discontinue and use a single agent with documented activity. Gentamicin should not be used as monotherapy for severe infections outside of the urinary tract (Gilbert 1998; Kanj 2019; Machuca 2017; Nicolau 1995; SCCM [Rhodes 2017]; Schmidt 2019; Shields 2016).

Sexually transmitted infections:

Gonococcal infection, uncomplicated (infection of the cervix, urethra, rectum, or pharynx; conjunctivitis) (alternative regimen reserved for patients with severe cephalosporin allergy) (off-label use): IM: 240 mg (administer as two 3 mL injections) in combination with oral azithromycin, each as a single dose (CDC [Workowski 2015]; Kirkcaldy 2014; Ross 2019). Note: Patients with pharyngeal infection treated with this regimen should have a test-of-cure performed. For treatment failure, consult an infectious diseases specialist and report to the CDC through state and local health departments within 24 hours of diagnosis (CDC [Workowski 2015]).

Pelvic inflammatory disease (including tubo-ovarian abscess) (off-label use): IV, IM: 3 to 5 mg/kg once daily or 2 mg/kg as a loading dose followed by 1.5 mg/kg every 8 hours; give as part of an appropriate combination regimen; after 24 to 48 hours of sustained clinical improvement, transition to oral therapy to complete at least 14 days of treatment (CDC [Workowski 2015]).

Surgical prophylaxis (alternative agent for select GI tract, GU tract, or gynecologic/obstetric procedures) (off-label use): IV: 5 mg/kg as a single dose within 60 minutes prior to surgical incision; give in combination with other antibiotics (procedure dependent) (ASHP/IDSA/SIS/SHEA [Bratzler 2013]). Note: In cases where extension of prophylaxis is warranted postoperatively, total duration should be ≤24 hours (Anderson 2019). Postoperative prophylaxis is not recommended in clean and clean-contaminated surgeries (CDC [Berríos-Torres 2017]).

Tularemia (off-label use): IV, IM: 5 mg/kg/day in 1 to 3 divided doses (Dennis 2001; IDSA [Stevens 2014]; Penn 2019; WHO 2007); duration is generally 7 to 10 days but should be extended for severe cases or for patients with a delayed response to treatment (IDSA [Stevens 2014]; Penn 2019).

Urinary tract infection, complicated (pyelonephritis or cystitis symptoms with signs/symptoms of systemic infection) (alternative agent): Note: Reserve for use when other long-acting parenteral antimicrobials or fluoroquinolones cannot be used due to allergy, intolerance, unmodifiable drug interactions, or resistance (Hooton 2019).

IV, IM: 5 mg/kg once at the initiation of therapy or once daily pending culture and susceptibility results. Duration of therapy depends on antimicrobial chosen to complete the regimen and ranges from 5 to 14 days (Hooton 2019; IDSA/ESCMID [Gupta 2011]; Ryanto 2019; Wie 2014).

Dosing: Geriatric

Refer to adult dosing.

Dosing: Pediatric

Note: Dosage should be based on an estimate of ideal body weight. In morbidly obese children, adolescents, and adults, dosage requirement may best be estimated using a dosing weight of IBW + 0.4 (TBW - IBW). Initial dosing recommendation presented; dosage should be individualized based upon serum concentration monitoring. Initial and periodic plasma drug concentrations (eg, peak and trough with conventional dosing, post dose level at a prespecified time with extended-interval dosing) should be determined, particularly in critically ill patients with serious infections or in disease states known to significantly alter aminoglycoside pharmacokinetics (eg, cystic fibrosis, burns, or major surgery). Some dosing based on tobramycin studies:

General dosing, susceptible infection: Note: Optimal dose and frequency not established in patients receiving ECMO; patient-specific considerations (eg, reason for ECMO) and variability with ECMO procedure itself make extrapolation of pharmacokinetic data and dosing to all patients receiving ECMO difficult; closely monitor serum concentrations and determine individual dosing needs in these patients.

Conventional dosing: Infants, Children, and Adolescents: IM, IV: 2 to 2.5 mg/kg/dose every 8 hours; some pediatric patients may require larger doses (ie, patients undergoing continuous hemofiltration, patients with major burns, febrile granulocytopenic patients); modify dose based on individual patient requirements as determined by renal function, serum drug concentrations, and patient-specific clinical parameters (Red Book [AAP 2018]).

Extended-interval dosing: Limited data available:

Weight-directed: Infants, Children, and Adolescents: IV: 4.5 to 7.5 mg/kg/dose every 24 hours in patients with normal renal function (Contopoulos-Ioannidis 2004; Red Book [AAP 2018]).

Age-directed: Based on data from 114 patients, the following has been suggested (McDade 2010):

Infants and Children ≥3 months to <2 years: IV: 9.5 mg/kg/dose every 24 hours.

Children 2 to <8 years: IV: 8.5 mg/kg/dose every 24 hours.

Children ≥8 years and Adolescents: IV: 7 mg/kg/dose every 24 hours.

CNS infection:

Meningitis (IDSA [Tunkel 2004]; IDSA [Tunkel 2017]):

Infants and Children: IV: 7.5 mg/kg/day divided every 8 hours.

Adolescents: IV: 5 mg/kg/day divided every 8 hours.

VP-shunt infection, ventriculitis, including health care associated: Limited data available; optimal dose not established (IDSA [Tunkel 2004]; IDSA [Tunkel 2017]; Mangi 1977; McCracken 1976): Intraventricular/intrathecal (use a preservative-free preparation):

Infants and Children: 1 to 2 mg/day.

Adolescents: Dosing recommendations not reported; however, in adults: 4 to 8 mg/day has been suggested.

Cystic fibrosis, pulmonary infection: Infants, Children, and Adolescents:

Conventional dosing: IM, IV: 3.3 mg/kg/dose every 8 hours (Flume 2009).

Extended-interval dosing: IV: 10 to 12 mg/kg/dose every 24 hours (Flume 2009; Van Meter 2009); Note: The CF Foundation recommends extended-interval dosing as preferred over conventional dosing.

Endocarditis, treatment:

Synergy dosing: Children and Adolescents: IV: 3 to 6 mg/kg/day divided every 8 hours in combination with other antibiotics; adjust dose to achieve a target peak concentration of 3 to 4 mcg/mL and trough concentration <1 mcg/mL (AHA [Baltimore 2015]).

S. aureus (methicillin-resistant), prosthetic valve/material: Infants, Children, and Adolescents: IV: 3 mg/kg/day divided every 8 hours in combination with vancomycin and rifampin (IDSA [Liu 2011]).

Treatment dose (eg, gram negative organisms): Children and Adolescents: IV: 7.5 mg/kg/day divided every 8 hours; adjust to achieve a target peak concentration of 5 to 10 mcg/ml and trough concentration <1 to 1.5 mcg/ml (AHA [Baltimore 2015]).

Intra-abdominal infection, complicated: Infants, Children, and Adolescents: IV: 3 to 7.5 mg/kg/day divided every 8 to 24 hours (IDSA [Solomkin 2010]).

Peritonitis (peritoneal dialysis) (ISPD [Warady 2012]): Limited data available: Infants, Children, and Adolescents:

Intermittent: Intraperitoneal:

Anuric: 0.6 mg/kg/dose every 24 hours in the long dwell.

Nonanuric: 0.75 mg/kg/dose every 24 hours in the long dwell.

Continuous: Intraperitoneal: Loading dose: 8 mg per liter of dialysate; maintenance dose: 4 mg per liter.

Surgical prophylaxis: Infants, Children, and Adolescents: IV: 2 to 2.5 mg/kg as a single dose; in children and adolescents, a dose of 2.5 mg/kg is typically suggested; administer within 60 minutes prior to surgical incision with or without other antibiotics (procedure dependent) (ASHP/IDSA [Bratzler 2013]; Red Book [AAP 2018]).

Tularemia: Infants, Children, and Adolescents: IM, IV: 5 to 6 mg/kg/day in 2 to 3 divided doses (WHO 2007); usual duration is 7 to 10 days; a shorter course (ie, 5 to 7 days) may be considered for mild disease; longer duration and concomitant antibiotics are required for severe illness (eg, meningitis) (IDSA [Stevens 2014]; Red Book [AAP 2018]).

UTI: Limited data available: Extended-interval dosing: Based on data from 90 patients (ages: 1 month to 12 years), the following age-directed dosing has been suggested (Carapetis 2001):

Infants and Children <5 years: IV: 7.5 mg/kg/dose every 24 hours.

Children 5 to 10 years: IV: 6 mg/kg/dose every 24 hours.

Children 11 to 12 years: IV: 4.5 mg/kg/dose every 24 hours.

Dosing: Obesity

In moderate obesity (TBW/IBW ≥1.25) or greater (eg, morbid obesity [TBW/IBW >2]), initial dosage requirement may be estimated using a dosing weight of IBW + 0.4 (TBW - IBW) (Traynor 1995).

Reconstitution

IV: May dilute in NS or D5W. In adults, dilution in 50 to 200 mL is recommended; premix admixtures commercially available for some dosages.

Administration

IM: Administer by deep IM route if possible.

IV: Infuse over 30 to 120 minutes.

Some penicillins (eg, carbenicillin, ticarcillin, and piperacillin) have been shown to inactivate aminoglycosides in vitro. This has been observed to a greater extent with tobramycin and gentamicin, while amikacin has shown greater stability against inactivation. Concurrent use of these agents may pose a risk of reduced antibacterial efficacy in vivo, particularly in the setting of profound renal impairment. However, definitive clinical evidence is lacking. If combination penicillin/aminoglycoside therapy is desired in a patient with renal dysfunction, separation of doses (if feasible), and routine monitoring of aminoglycoside levels, CBC, and clinical response should be considered.

Intraventricular (off-label route): Use preservative-free preparations only. When administered through a ventricular drain, clamp drain for 15 to 60 minutes before opening the drain to allow gentamicin solution to equilibrate in the cerebrospinal fluid (IDSA [Tunkel 2004]; IDSA [Tunkel 2017]).

Storage

Store intact vials and premixed bags at 20°C to 25°C (68°F to 77°F). Protect from freezing. IV infusion solutions mixed in NS or D5W are stable for 48 hours at room temperature and refrigeration (Goodwin 1991).

Drug Interactions

Agalsidase Alfa: Gentamicin (Systemic) may diminish the therapeutic effect of Agalsidase Alfa. Avoid combination

Agalsidase Beta: Gentamicin (Systemic) may diminish the therapeutic effect of Agalsidase Beta. Avoid combination

Amphotericin B: May enhance the nephrotoxic effect of Aminoglycosides. Monitor therapy

Arbekacin: May enhance the nephrotoxic effect of Aminoglycosides. Arbekacin may enhance the ototoxic effect of Aminoglycosides. Monitor therapy

Ataluren: May enhance the adverse/toxic effect of Aminoglycosides. Specifically, an increased risk of nephrotoxicity may occur with the concomitant use of ataluren and aminoglycosides. Avoid combination

BCG (Intravesical): Antibiotics may diminish the therapeutic effect of BCG (Intravesical). Avoid combination

BCG Vaccine (Immunization): Antibiotics may diminish the therapeutic effect of BCG Vaccine (Immunization). Monitor therapy

Bisphosphonate Derivatives: Aminoglycosides may enhance the hypocalcemic effect of Bisphosphonate Derivatives. Monitor therapy

Botulinum Toxin-Containing Products: Aminoglycosides may enhance the neuromuscular-blocking effect of Botulinum Toxin-Containing Products. Monitor therapy

Capreomycin: May enhance the neuromuscular-blocking effect of Aminoglycosides. Monitor therapy

CARBOplatin: Aminoglycosides may enhance the ototoxic effect of CARBOplatin. Especially with higher doses of carboplatin. Monitor therapy

Cardiac Glycosides: Aminoglycosides may decrease the serum concentration of Cardiac Glycosides. This effect has only been demonstrated with oral aminoglycoside administration. Monitor therapy

Cefazedone: May enhance the nephrotoxic effect of Aminoglycosides. Monitor therapy

Cephalosporins (2nd Generation): May enhance the nephrotoxic effect of Aminoglycosides. Monitor therapy

Cephalosporins (3rd Generation): May enhance the nephrotoxic effect of Aminoglycosides. Monitor therapy

Cephalosporins (4th Generation): May enhance the nephrotoxic effect of Aminoglycosides. Monitor therapy

Cephalothin: May enhance the nephrotoxic effect of Aminoglycosides. Monitor therapy

Cephradine: May enhance the nephrotoxic effect of Aminoglycosides. Monitor therapy

Cholera Vaccine: Antibiotics may diminish the therapeutic effect of Cholera Vaccine. Management: Avoid cholera vaccine in patients receiving systemic antibiotics, and within 14 days following the use of oral or parenteral antibiotics. Avoid combination

CISplatin: May enhance the nephrotoxic effect of Aminoglycosides. Monitor therapy

Colistimethate: Aminoglycosides may enhance the nephrotoxic effect of Colistimethate. Aminoglycosides may enhance the neuromuscular-blocking effect of Colistimethate. Consider therapy modification

CycloSPORINE (Systemic): Aminoglycosides may enhance the nephrotoxic effect of CycloSPORINE (Systemic). Monitor therapy

Distigmine: Aminoglycosides may diminish the therapeutic effect of Distigmine. Monitor therapy

Foscarnet: May enhance the nephrotoxic effect of Aminoglycosides. Avoid combination

Lactobacillus and Estriol: Antibiotics may diminish the therapeutic effect of Lactobacillus and Estriol. Monitor therapy

Loop Diuretics: May enhance the adverse/toxic effect of Aminoglycosides. Specifically, nephrotoxicity and ototoxicity. Monitor therapy

Mannitol (Systemic): May enhance the nephrotoxic effect of Aminoglycosides. Avoid combination

Mecamylamine: Aminoglycosides may enhance the neuromuscular-blocking effect of Mecamylamine. Avoid combination

Methoxyflurane: Aminoglycosides may enhance the nephrotoxic effect of Methoxyflurane. Avoid combination

Neuromuscular-Blocking Agents: Aminoglycosides may enhance the respiratory depressant effect of Neuromuscular-Blocking Agents. Monitor therapy

Nonsteroidal Anti-Inflammatory Agents: May decrease the excretion of Aminoglycosides. Data only in premature infants. Monitor therapy

Oxatomide: May enhance the ototoxic effect of Aminoglycosides. Monitor therapy

Penicillins: May decrease the serum concentration of Aminoglycosides. Primarily associated with extended spectrum penicillins, and patients with renal dysfunction. Exceptions: Amoxicillin; Ampicillin; Bacampicillin; Cloxacillin; Dicloxacillin; Nafcillin; Oxacillin; Penicillin G (Parenteral/Aqueous); Penicillin G Benzathine; Penicillin G Procaine; Penicillin V Benzathine; Penicillin V Potassium. Consider therapy modification

Sodium Picosulfate: Antibiotics may diminish the therapeutic effect of Sodium Picosulfate. Management: Consider using an alternative product for bowel cleansing prior to a colonoscopy in patients who have recently used or are concurrently using an antibiotic. Consider therapy modification

Tenofovir Products: Aminoglycosides may increase the serum concentration of Tenofovir Products. Tenofovir Products may increase the serum concentration of Aminoglycosides. Monitor therapy

Typhoid Vaccine: Antibiotics may diminish the therapeutic effect of Typhoid Vaccine. Only the live attenuated Ty21a strain is affected. Management: Vaccination with live attenuated typhoid vaccine (Ty21a) should be avoided in patients being treated with systemic antibacterial agents. Use of this vaccine should be postponed until at least 3 days after cessation of antibacterial agents. Consider therapy modification

Vancomycin: May enhance the nephrotoxic effect of Aminoglycosides. Monitor therapy

Test Interactions

Some penicillin derivatives may accelerate the degradation of aminoglycosides in vitro, leading to a potential underestimation of aminoglycoside serum concentration.

Adverse Reactions

Frequency not defined.

Cardiovascular: Edema, hypertension, hypotension, phlebitis, thrombophlebitis

Central nervous system: Abnormal gait, ataxia, brain disease, confusion, depression, dizziness, drowsiness, headache, lethargy, myasthenia, numbness, paresthesia, peripheral neuropathy, pseudomotor cerebri, seizure, vertigo

Dermatologic: Alopecia, erythema, pruritus, skin rash, urticaria

Endocrine & metabolic: Hypocalcemia, hypokalemia, hypomagnesemia, hyponatremia, weight loss

Gastrointestinal: Anorexia, Clostridioides (formerly Clostridium) difficile-associated diarrhea, decreased appetite, enterocolitis, nausea, sialorrhea, stomatitis, vomiting

Genitourinary: Casts in urine (hyaline, granular), Fanconi-like syndrome (infants and adults; high dose, prolonged course), oliguria, proteinuria

Hematologic & oncologic: Agranulocytosis, anemia, eosinophilia, granulocytopenia, leukopenia, purpura, reticulocytopenia, reticulocytosis, splenomegaly, thrombocytopenia

Hepatic: Hepatomegaly, increased liver enzymes

Hypersensitivity: Anaphylaxis, anaphylactoid reaction, hypersensitivity reaction

Local: Injection site reaction, pain at injection site

Neuromuscular & skeletal: Arthralgia, muscle cramps, muscle fatigue (myasthenia gravis-like syndrome), muscle twitching, tremor, weakness

Ophthalmic: Visual disturbance

Otic: Auditory impairment, hearing loss (associated with persistently increased serum concentrations; early toxicity usually affects high-pitched sound), tinnitus

Renal: Decreased creatinine clearance, decreased urine specific gravity, increased blood urea nitrogen, increased serum creatinine, polyuria, renal failure (high trough serum concentrations), renal tubular necrosis

Respiratory: Dyspnea, laryngeal edema, pulmonary fibrosis, respiratory depression

Miscellaneous: Fever

ALERT: U.S. Boxed Warning

Toxicity:

Ensure that patients treated with aminoglycosides are under close clinical observation because of the potential toxicity associated with their use.

As with other aminoglycosides, gentamicin is potentially nephrotoxic. The risk of nephrotoxicity is greater in patients with impaired renal function and in those who receive high dosages or prolonged therapy.

Neurotoxicity, manifested by ototoxicity, both vestibular and auditory, can occur in patients treated with gentamicin, primarily in those with preexisting renal damage and in patients with healthy renal function treated with higher doses and/or for longer periods than recommended. Aminoglycoside-induced ototoxicity is usually irreversible. Other manifestations of neurotoxicity may include numbness, skin tingling, muscle twitching, and convulsions.

Closely monitor renal and eighth cranial nerve functions, especially in patients with known or suspected reduced renal function at onset of therapy, and also in those whose renal function is initially normal but who develop signs of renal dysfunction during therapy. Examine urine for decreased specific gravity, increased excretion of protein, and the presence of cells or casts. Periodically determine serum urea nitrogen (BUN), serum creatinine, or creatinine clearance (CrCl). When feasible, it is recommended that serial audiograms be obtained in patients old enough to be tested, particularly high-risk patients. Evidence of ototoxicity (dizziness, vertigo, tinnitus, roaring in the ears, or hearing loss) or nephrotoxicity requires dosage adjustment or discontinuance of the drug. As with the other aminoglycosides, on rare occasions, changes in renal and eighth cranial nerve function may not manifest until soon after completion of therapy.

Monitor serum concentrations of aminoglycosides when feasible to ensure adequate levels and to avoid potentially toxic levels. When monitoring gentamicin peak concentrations, adjust dosage so that prolonged levels above 12 mcg/mL are avoided. When monitoring gentamicin trough concentrations, adjust dosage so that levels above 2 mcg/mL are avoided. Excessive peak or trough serum concentrations of aminoglycosides may increase the risk of renal and eighth cranial nerve toxicity. In the event of overdose or toxic reactions, hemodialysis may aid in the removal of gentamicin from the blood, especially if renal function is, or becomes, compromised. The rate of removal of gentamicin is considerably less by peritoneal dialysis than by hemodialysis.

Avoid concurrent and/or sequential systemic or topical use of other potentially neurotoxic and/or nephrotoxic drugs, such as cisplatin, cephaloridine, kanamycin, amikacin, neomycin, polymyxin B, colistin, paromomycin, streptomycin, tobramycin, vancomycin, and viomycin. Other factors that may increase patient risk of toxicity are advanced age and dehydration.

Avoid the concurrent use of gentamicin with potent diuretics, such as ethacrynic acid or furosemide, since certain diuretics by themselves may cause ototoxicity. In addition, when administered intravenously (IV), diuretics may enhance aminoglycoside toxicity by altering the antibiotic concentration in serum and tissue.

Pregnancy:

Aminoglycosides can cause fetal harm when administered to a pregnant woman.

Warnings/Precautions

Concerns related to adverse effects:

• Hypersensitivity: Cross-sensitivity to other aminoglycosides may occur.

• Nephrotoxicity: [US Boxed Warning]: May cause nephrotoxicity; usual risk factors include preexisting renal impairment, concomitant nephrotoxic medications, advanced age and dehydration. Discontinue treatment if signs of nephrotoxicity occur; renal damage is usually reversible.

• Neuromuscular blockade and respiratory paralysis: May cause neuromuscular blockade and respiratory paralysis; especially when given soon after anesthesia or neuromuscular blockers.

• Neurotoxicity: [US Boxed Warning]: May cause neurotoxicity; usual risk factors include preexisting renal impairment, concomitant neuro-/nephrotoxic medications, advanced age and dehydration. Ototoxicity is proportional to the amount of drug given and the duration of treatment. Tinnitus or vertigo may be indications of vestibular injury and impending bilateral irreversible damage. Discontinue treatment if signs of ototoxicity occur.

• Superinfection: Prolonged use may result in fungal or bacterial superinfection, including Clostridioides (formerly Clostridium) difficile-associated diarrhea (CDAD) and pseudomembranous colitis; CDAD has been observed >2 months postantibiotic treatment.

Disease-related concerns:

• Electrolyte abnormalities: Use with caution in patients with hypocalcemia, hypokalemia, or hypomagnesemia.

• Hearing impairment: Use with caution in patients with preexisting vertigo, tinnitus, or hearing loss.

• Neuromuscular disorders: Use with caution in patients with neuromuscular disorders, including myasthenia gravis.

• Renal impairment: Use with caution in patients with preexisting renal insufficiency; dosage modification required.

Special populations:

• Pregnancy: [US Boxed Warning]: Aminoglycosides may cause fetal harm if administered to a pregnant woman.

Concurrent drug therapy issues:

• Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information.

• Neurotoxic and/or nephrotoxic drugs: [US Boxed Warning]: Avoid concomitant or sequential use of other neurotoxic and/or nephrotoxic drugs (eg, cisplatin, polymyxin B, colistin, vancomycin, other aminoglycosides).

• Potent diuretics: [US Boxed Warning]: Avoid concomitant use with potent diuretics (eg, ethacrynic acid, furosemide) since diuretics themselves may cause ototoxicity and may enhance aminoglycoside toxicity.

Other warnings/precautions:

• Long-term use: Risk of toxicity is increased with extended duration of administration; additional monitoring may be required with long-term use.

• Surgical irrigation: May be almost completely systemically absorbed after local irrigation and/or topical application (except to the urinary bladder) during surgical procedures. Consider potential for nephrotoxicity, neuromuscular blockade, ototoxicity, and respiratory paralysis when administering aminoglycosides in this manner.

Monitoring Parameters

Urinalysis, urine output, BUN, serum creatinine, plasma gentamicin levels (as appropriate to dosing method). Levels are typically obtained before and after the third dose in conventional dosing. Hearing should be tested before, during, and after treatment; particularly in those at risk for ototoxicity or who will be receiving prolonged therapy (>2 weeks).

Some penicillin derivatives may accelerate the degradation of aminoglycosides in vitro. This may be clinically-significant for certain penicillin (ticarcillin, piperacillin, carbenicillin) and aminoglycoside (gentamicin, tobramycin) combination therapy in patients with significant renal impairment. Close monitoring of aminoglycoside levels is warranted.

Pregnancy Risk Factor

D

Pregnancy Considerations

Gentamicin crosses the placenta.

[US Boxed Warning]: Aminoglycosides may cause fetal harm if administered to a pregnant woman. There are several reports of total irreversible bilateral congenital deafness in children whose mothers received another aminoglycoside (streptomycin) during pregnancy. Although serious side effects to the fetus/infant have not been reported following maternal use of all aminoglycosides, a potential for harm exists.

Due to pregnancy-induced physiologic changes, some pharmacokinetic parameters of gentamicin may be altered (Popović 2007). Gentamicin use has been evaluated for various infections in pregnant women including the treatment of acute pyelonephritis (Jolley 2010) and as an alternative antibiotic for prophylactic use prior to cesarean delivery (Bratzler 2013).

Patient Education

What is this drug used for?

• It is used to treat bacterial infections.

Frequently reported side effects of this drug

• Lack of appetite

• Weight loss

• Nausea

• Vomiting

• Increased saliva

• Mouth irritation

• Mouth sores

• Hair loss

• Joint pain

Other side effects of this drug: Talk with your doctor right away if you have any of these signs of:

• Kidney problems like urinary retention, hematuria, change in amount of urine passed, or weight gain.

• Change in balance

• Severe dizziness

• Passing out

• Hearing loss

• Tinnitus

• Severe loss of strength and energy

• Muscle weakness

• Burning or numbness feeling

• Twitching

• Seizures

• Shortness of breath

• Confusion

• Depression

• Vision changes

• Severe headache

• Signs of a significant reaction like wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat.

Note: This is not a comprehensive list of all side effects. Talk to your doctor if you have questions.

Consumer Information Use and Disclaimer: This information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not specific medical advice and does not replace information you receive from the healthcare provider. You must talk with the healthcare provider for complete information about the risks and benefits of using this medicine.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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