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Gentamicin Dosage

Medically reviewed on March 12, 2018.

Applies to the following strengths: 40 mg/mL; 10 mg/mL; 60 mg/50 mL-0.9%; 70 mg/50 mL-0.9%; 80 mg/50 mL-0.9%; 80 mg/100 mL-0.9%; 90 mg/100 mL-0.9%; 100 mg/100 mL-0.9%; 60 mg/100 mL-0.9%; 40 mg/50 mL-0.9%; 120 mg/100 mL-0.9%; 100 mg/50 mL-0.9%

Usual Adult Dose for Bacteremia

1.5 to 2 mg/kg loading dose, followed by 1 to 1.7 mg/kg IV or IM every 8 hours or 5 to 7 mg/kg IV every 24 hours
Duration of therapy: 14 days, depending on the site, nature, and severity of the bacteremia

Comments: Limiting the duration of gentamicin therapy may help limit toxicity. Once the patient is stable for at least 48 hours, less toxic IV or oral antibiotic therapy may be considered according to microbiology sensitivity data.

Usual Adult Dose for Bacterial Endocarditis Prophylaxis

1.5 mg/kg (maximum 120 mg) IV or IM once within 30 minutes of starting the procedure

Comments: For high risk patients, in addition to gentamicin, ampicillin 2 g is given IV or IM 30 minutes prior to the procedure, followed by ampicillin 1 g IV/IM or amoxicillin 1 g orally 6 hours later. In penicillin-allergic patients, vancomycin 1 g is infused IV 1 to 2 hours prior to the procedure.

Usual Adult Dose for Bacterial Infection

1.5 to 2 mg/kg loading dose, followed by 1 to 1.7 mg/kg IV or IM every 8 hours, or 5 to 7 mg/kg IV every 24 hours
Duration of therapy: 7 to 21 days, depending on the nature and severity of the infection

Comments: Limiting the duration of gentamicin therapy may help limit toxicity. Once the patient is stable for at least 48 hours, less toxic IV or oral antibiotic therapy may be considered according to microbiology sensitivity data.

Usual Adult Dose for Brucellosis

2 mg/kg loading dose, followed by 1.7 mg/kg IV or IM every 8 hours or 5 mg/kg IV every 24 hours
Duration of therapy: For the first 2 to 3 weeks of antibiotic therapy

Comments: Oral doxycycline or sulfamethoxazole/trimethoprim should be continued for at least 6 weeks.

Usual Adult Dose for Burns - External

2 to 2.5 mg/kg loading dose, followed by 1.7 to 2 mg/kg IV every 8 hours
Duration of therapy: 10 to 14 days, depending on the nature and severity of the infection

Usual Adult Dose for Cystic Fibrosis

5 to 10 mg/kg/day in 2 to 4 divided doses
Duration of therapy: Parenteral therapy should be continued for about 14 to 21 days, depending on the nature and severity of the infection and improvement of pulmonary function.

Usual Adult Dose for Endocarditis

American Heart Association (AHA) recommendations:
Native valve infections due to highly penicillin-susceptible viridans Group streptococci and S bovis (MIC <=0.12 mcg/mL): 3 mg/kg IV or IM once every 24 hours in combination with aqueous penicillin G sodium or ceftriaxone
Duration of therapy: 2 weeks; continue other antibiotic for 4 weeks

Native valve infections due to relatively penicillin-resistant S viridans and S bovis (MIC >0.12 mcg/mL and <=0.5 mcg/mL): 3 mg/kg IV or IM once every 24 hours in combination with aqueous penicillin G sodium or ceftriaxone
Duration of therapy: 2 weeks; continue other antibiotic for 4 weeks

Prosthetic valve infections due to S viridans and S bovis: 3 mg/kg IV or IM once every 24 hours in combination with aqueous penicillin G sodium or ceftriaxone
Duration of therapy: 2 weeks; continue other antibiotic for 6 weeks

Native valve infections due to staphylococci: 1.5 mg/kg IV or IM every 12 hours or 1 mg/kg every 8 hours, in combination with nafcillin, oxacillin, or cefazolin
Duration of therapy: 3 to 5 days; continue other antibiotic for 6 weeks

Prosthetic valve infections due to staphylococci: 1.5 mg/kg IV or IM every 12 hours or 1 mg/kg every 8 hours, in combination with nafcillin or oxacillin, plus rifampin, or vancomycin plus rifampin
Duration of therapy: 2 weeks; continue other antibiotics for at least 6 weeks

Native valve or prosthetic valve infections due to susceptible enterococci: 1 mg/kg IV or IM every 8 hours, in combination with ampicillin, aqueous penicillin G sodium, or vancomycin
Duration of therapy: 4 to 6 weeks; continue other antibiotic for 6 weeks

Native valve or prosthetic valve infections due to penicillin-resistant enterococci: 1 mg/kg IV or IM every 8 hours, in combination with ampicillin-sulbactam or vancomycin
Duration of therapy: 6 weeks

Comments: Refer to current published guidelines for detailed recommendations.

Usual Adult Dose for Endometritis

2 mg/kg loading dose, followed by 1.5 mg/kg IV or IM every 8 hours
Duration of therapy: Parenteral therapy should be continued for at least 24 hours after the patient has remained afebrile, pain free, and the leukocyte count has normalized.

Usual Adult Dose for Febrile Neutropenia

2 mg/kg loading dose, followed by 1.7 mg/kg IV every 8 hours
Duration of therapy: Once the patient is stable, afebrile for 24 hours, and the absolute neutrophil count is greater than 500/mm3, oral antibiotics may be substituted if antibiotic therapy is to be continued.

Usual Adult Dose for Intraabdominal Infection

2 mg/kg loading dose, followed by 1.7 mg/kg IV every 8 hours or 5 mg/kg IV every 24 hours
Duration of therapy: 14 days, depending on the nature and severity of the infection

Comments: Less toxic antibiotics may be substituted once the patient is stable for at least 48 hours.

Usual Adult Dose for Meningitis

2 mg/kg loading dose, followed by 1.7 mg/kg IV or IM every 8 hours
Duration of therapy: Parenteral therapy should be continued for at least 1 week after the patient becomes afebrile and cerebrospinal fluid normalizes.

Usual Adult Dose for Osteomyelitis

1.5 to 2 mg/kg loading dose, followed by 1 to 1.7 mg/kg IV or IM every 8 hours or 5 to 7 mg/kg IV every 24 hours
Duration of therapy: 4 to 6 weeks, depending on the nature and severity of the infection; chronic osteomyelitis may require an additional 1 to 2 months of oral antibiotics

Comments: Limiting the duration of gentamicin therapy may help limit toxicity. Once the patient is stable for at least 48 hours, less toxic IV or oral antibiotic therapy may be considered according to microbiology sensitivity data.

Usual Adult Dose for Pelvic Inflammatory Disease

2 mg/kg loading dose, followed by 1.5 mg/kg IV or IM every 8 hours or 5 mg/kg IV every 24 hours
Duration of therapy: Parenteral therapy should be continued for at least 24 hours after clinical improvement and should be followed by oral doxycycline or clindamycin for a total 14 day course.

Usual Adult Dose for Peritonitis

IV: 2 mg/kg loading dose, followed by 1.7 mg/kg IV every 8 hours or 5 mg/kg IV every 24 hours
Duration of therapy: Therapy should be continued for about 14 days, depending on the nature and severity of the infection.

Comments: Limiting the duration of gentamicin therapy may help limit toxicity. Once the patient is stable for at least 48 hours, less toxic IV or oral antibiotic therapy may be considered according to microbiology sensitivity data.

Intraperitoneally in CAPD patients: 0.6 to 0.75 mg/kg intraperitoneally once a day or 16 to 20 mg per every 2 L dialysate

Usual Adult Dose for Plague

2 mg/kg loading dose, followed by 1.7 mg/kg IV or IM every 8 hours or 5 mg/kg IV every 24 hours
Duration of therapy: Therapy should be continued for about 10 to 14 days, depending on the nature and severity of the infection.

Comments: Limiting the duration of gentamicin therapy may help limit toxicity. Once the patient's condition improves, less toxic IV or oral antibiotic therapy may be considered according to microbiology sensitivity data.

Usual Adult Dose for Pneumonia

2 mg/kg loading dose, followed by 1.7 mg/kg IV or IM every 8 hours or 5 mg/kg IV every 24 hours
Duration of therapy: Therapy should be continued for 14 to 21 days, depending on the nature and severity of the infection.

Comments: Limiting the duration of gentamicin therapy may help limit toxicity. Once the patient is stable for at least 48 hours, less toxic IV or oral antibiotic therapy may be considered according to microbiology sensitivity data.

Usual Adult Dose for Pyelonephritis

2 mg/kg loading dose, followed by 1.7 mg/kg IV every 8 hours or 5 mg/kg IV every 24 hours
Duration of therapy: Therapy should be continued for about 7 to 14 days, depending on the nature and severity of the infection.

Comments: Limiting the duration of gentamicin therapy may help limit toxicity. Once the patient is stable for at least 48 hours, less toxic IV or oral antibiotic therapy may be considered according to microbiology sensitivity data.

Usual Adult Dose for Skin or Soft Tissue Infection

1.5 to 2 mg/kg loading dose, followed by 1 to 1.7 mg/kg IV or IM every 8 hours or 5 to 7 mg/kg IV every 24 hours
Duration of therapy: Therapy should be continued for at least 10 to 14 days, or until 3 days postacute inflammation, depending on the nature and severity of the infection; for severe infections, such as diabetic soft tissue infections, 14 to 21 days of therapy may be required

Comments: Limiting the duration of gentamicin therapy may help limit toxicity. Once the patient is stable for at least 48 hours, less toxic IV or oral antibiotic therapy may be considered according to microbiology sensitivity data.

Usual Adult Dose for Surgical Prophylaxis

1.5 to 2 mg/kg (maximum 120 mg) IV or IM once at induction of anesthesia

Usual Adult Dose for Tularemia

1.5 to 2 mg/kg loading dose, followed by 1 to 1.7 mg/kg IV or IM every 8 hours or 5 to 7 mg/kg IV every 24 hours
Duration of therapy: Therapy should be continued for about 10 to 14 days, depending on the nature and severity of the infection.

Comments: Once the patient's condition improves, less toxic IV or oral antibiotic therapy may be considered according to microbiology sensitivity data.

Usual Pediatric Dose for Bacterial Infection

0 to 4 weeks, birthweight <1200 g: 2.5 mg/kg IV or IM every 18 to 24 hours
0 to 1 week, birthweight >=1200 g: 2.5 mg/kg IV or IM every 12 hours
1 to 4 weeks, birthweight 1200 to 2000 g: 2.5 mg/kg IV or IM every 8 to 12 hours
1 to 4 weeks, birthweight >=2000 g: 2.5 mg/kg IV or IM every 8 hours

>1 month: 1 to 2.5 mg/kg IV or IM every 8 hours

Usual Pediatric Dose for Bacterial Endocarditis Prophylaxis

1.5 mg/kg IV or IM once within 30 minutes of starting the procedure

Comments: For high risk patients, in addition to gentamicin, ampicillin 50 mg/kg (maximum 2 g) is given IV or IM 30 minutes prior to the procedure, followed by ampicillin 25 mg/kg IV/IM or amoxicillin 25 mg/kg orally 6 hours later. In penicillin-allergic patients, vancomycin 20 mg/kg IV is infused over 1 to 2 hours instead of ampicillin/amoxicillin.

Usual Pediatric Dose for Endocarditis

AHA recommendations:
Native valve infections due to highly penicillin-susceptible viridans Group streptococci and S bovis (MIC <=0.12 mcg/mL): 3 mg/kg IV or IM once every 24 hours or 1 mg/kg every 8 hours in combination with aqueous penicillin G sodium or ceftriaxone
Duration of therapy: 2 weeks; continue other antibiotic for 4 weeks

Native valve infections due to relatively penicillin-resistant S viridans and S bovis (MIC >0.12 mcg/mL and <=0.5 mcg/mL): 3 mg/kg IV or IM once every 24 hours or 1 mg/kg every 8 hours in combination with aqueous penicillin G sodium or ceftriaxone
Duration of therapy: 2 weeks; continue other antibiotic for 4 weeks

Prosthetic valve infections due to S viridans and S bovis: 3 mg/kg IV or IM once every 24 hours or 1 mg/kg every 8 hours in combination with aqueous penicillin G sodium or ceftriaxone
Duration of therapy: 2 weeks; continue other antibiotic for 6 weeks

Native valve infections due to staphylococci: 1 mg/kg IV or IM every 8 hours, in combination with nafcillin, oxacillin, or cefazolin
Duration of therapy: 3 to 5 days; continue other antibiotic for 6 weeks

Prosthetic valve infections due to staphylococci: 1 mg/kg every 8 hours, in combination with nafcillin or oxacillin, plus rifampin, or vancomycin plus rifampin
Duration of therapy: 2 weeks; continue other antibiotics for at least 6 weeks

Native valve or prosthetic valve infections due to susceptible enterococci: 1 mg/kg IV or IM every 8 hours, in combination with ampicillin, aqueous penicillin G sodium, or vancomycin
Duration of therapy: 4 to 6 weeks; continue other antibiotic for 6 weeks

Native valve or prosthetic valve infections due to penicillin-resistant enterococci: 1 mg/kg IV or IM every 8 hours, in combination with ampicillin-sulbactam or vancomycin
Duration of therapy: 6 weeks

Comments: Refer to current published guidelines for detailed recommendations.

Usual Pediatric Dose for Surgical Prophylaxis

2 mg/kg IV once at induction of anesthesia

Renal Dose Adjustments

PARENTERAL:
Dosage should be adjusted in renal insufficiency. Various nomograms and methods have been proposed for determining the dosage in renally impaired adult patients - reduced doses at fixed intervals or normal doses at prolonged intervals. Regimens are ideally based on individualized pharmacokinetic dosing.

Adults:
The following adjustments to the maintenance dose have been suggested (modified from Sarubbi and Hull, 1978):
CrCl 70 to 80 mL/min: 76% to 91% of the loading dose every 8 to 12 hours
CrCl 60 to 70 mL/min: 71% to 88% of the loading dose every 8 to 12 hours
CrCl 50 to 60 mL/min: 65% to 84% of the loading dose every 8 to 12 hours
CrCl 40 to 50 mL/min: 72% to 92% of the loading dose every 12 to 24 hours
CrCl 30 to 40 mL/min: 63% to 92% of the loading dose every 12 to 24 hours
CrCl 20 to 30 mL/min: 50% to 81% of the loading dose every 12 to 24 hours
CrCl 10 to 20 mL/min: 34% to 75% of the loading dose every 12 to 24 hours
CrCl <10 mL/min: 21% to 47% of the loading dose every 24 hours or a one-time loading dose with subsequent doses based on serum concentrations, estimated clearance, and the patient's condition

Adults, extended-interval dosing (dose and interval adjustment):
CrCl >80 mL/min: 5 to 7 mg/kg every 24 hours
CrCl 60 to 70 mL/min: 4 to 5.5 mg/kg every 24 hours
CrCl 50 mL/min: 3.5 to 5 mg/kg every 24 hours
CrCl 30 to 40 mL/min: 2.5 to 3.5 mg/kg every 24 hours
CrCl 20 mL/min: 4 to 5 mg/kg every 48 hours
CrCl 10 mL/min: 3 to 4 mg/kg every 48 hours

Adults, extended-interval dosing (constant dose with interval adjustment):
CrCl >60 mL/min: 7 mg/kg every 24 hours
CrCl 40 to 60 mL/min: 7 mg/kg every 36 hours
CrCl 20 to 40 mL/min: 7 mg/kg every 48 hours; monitor serum levels
CrCl <20 mL/min: 7 mg/kg once; repeat when trough level <1 mcg/mL

INHALATION:
If nephrotoxicity is suspected, therapy should be discontinued until gentamicin serum concentrations fall below 2 mcg/mL.

Liver Dose Adjustments

No adjustment recommended.

Dose Adjustments

In obese patients, the appropriate parenteral dose may be calculated by using the estimated lean body weight plus 40% of the excess as the basic weight on which to figure mg/kg.

Precautions

US BOXED WARNING:
-TOXICITY: Closely observe patients treated with aminoglycosides because of the potential toxicity associated with their use. Other factors which may increase patient risk to toxicity are advanced age and dehydration. In the event of overdose or toxic reactions, hemodialysis may aid in the removal of this drug from the blood especially if renal function is/becomes compromised. The rate of drug removal is considerably lower by peritoneal dialysis than it is by hemodialysis.
-NEPHROTOXICITY: As with other aminoglycosides, this drug is potentially nephrotoxic. The risk of nephrotoxicity is greater in patients with impaired renal function and in those who receive high dosage or prolonged therapy.
-OTOTOXICITY: Neurotoxicity manifested by ototoxicity, both vestibular and auditory, can occur in patients, primarily in those with pre-existing renal damage and in patients with normal 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.
-MONITORING: Closely observe patients treated with aminoglycosides because of the potential toxicity associated with their use. Monitor renal and eighth-nerve function, especially in patients with known or suspected renal impairment at the 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 proteins, and the presence of cells or casts. Measure blood urea nitrogen, serum creatinine, or creatinine clearance periodically. When feasible, obtain serial audiograms in patients old enough to be tested (particularly high risk patients), and monitor serum concentrations of aminoglycosides to assure 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 and/or trough serum concentrations of aminoglycosides may increase the risk of renal and eighth cranial nerve toxicity. Evidence of ototoxicity (dizziness, vertigo, tinnitus, roaring in the ears, and hearing loss) or nephrotoxicity requires discontinuation of the drug or dosage adjustment. As with the other aminoglycosides, on rare occasions changes in renal and eighth cranial nerve function may not become manifest until soon after completion of therapy.
-CONCURRENT THERAPY: Avoid concurrent and/or sequential systemic or topical use of other potentially neurotoxic and/or nephrotoxic drugs (e.g., cisplatin, cephaloridine, kanamycin, amikacin, neomycin, polymyxin B, colistin, paromomycin, streptomycin, tobramycin, vancomycin, viomycin). Avoid concomitant use with potent diuretics (ethacrynic acid or furosemide) since diuretics by themselves may cause ototoxicity, and when administered intravenously, they may enhance aminoglycoside toxicity by altering antibiotic concentrations in serum and tissue.
-FETAL HARM: Aminoglycosides can cause fetal harm when administered to a pregnant woman.

Consult WARNINGS section for additional precautions.

NARROW THERAPEUTIC INDEX:
-This drug should be considered a narrow therapeutic index (NTI) drug as small differences in dose or blood concentrations may lead to serious therapeutic failures or adverse drug reactions.
Recommendations:
-Generic substitution should be done cautiously, if at all, as current bioequivalence standards are generally insufficient for NTI drugs.
-Additional and/or more frequent monitoring should be done to ensure receipt of an effective dose while avoiding unnecessary toxicities.

It is desirable to limit the duration of treatment with aminoglycosides to short term. To prevent increased toxicity due to excessive blood levels, dosage should not exceed 5 mg/kg/day unless serum levels are monitored. With treatment >10 days, monitoring of renal, auditory, and vestibular functions is recommended.

In patients with extensive burns, altered pharmacokinetics may result in reduced serum levels of aminoglycosides. In such patients treated with gentamicin, measurement of serum levels is recommended as a basis for dosage adjustment.

Dialysis

Gentamicin is 30% removed during hemodialysis. The dose should be administered following dialysis.

Hemodialysis and peritoneal dialysis: One-time loading dose, with subsequent doses based on serum concentrations, estimated clearance, and the patient's condition

or 2 to 4 mg/kg every 48 hours

Other Comments

It is desirable to measure periodically both peak and trough serum levels of gentamicin when feasible during therapy to assure adequate but not excessive drug levels. When monitoring peak levels after IM or IV administration, dosage should be adjusted so that prolonged levels >12 mcg/mL are avoided. When monitoring trough levels (just prior to the next dose), dosage should be adjusted so that levels >2 mcg/mL are avoided. The usual duration of treatment for all patients is 7 to 10 days. In difficult and complicated infections, a longer course of therapy may be necessary.

Further information

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

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