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Gentamicin (Systemic)

Pronunciation

Pronunciation

(jen ta MYE sin)

Index Terms

  • Gentamicin Sulfate

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Solution, Injection:

Generic: 10 mg/mL (2 mL); 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); 80 mg (50 mL, 100 mL); 90 mg (100 mL); 100 mg (50 mL, 100 mL); 120 mg (100 mL); 10 mg/mL (6 mL, 8 mL, 10 mL)

Pharmacologic Category

  • Antibiotic, Aminoglycoside

Pharmacology

Interferes with bacterial protein synthesis by binding to 30S and 50S ribosomal subunits resulting in a defective bacterial cell membrane

Absorption

Intramuscular: Rapid and complete; Oral: Poorly absorbed (<2%)

Distribution

Primarily into extracellular fluid (highly hydrophilic); high concentration in the renal cortex; minimal penetration to CSF and ocular tissues via IV route; small amounts distribute into bile, sputum, saliva, and tears

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: 0.2-0.3 L/kg

Relative diffusion from blood into CSF: Minimal even with inflammation

CSF:blood level ratio: Normal meninges: Nil; Inflamed meninges: 10% to 30%

Excretion

Urine (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: 30-90 minutes; IV: 30 minutes after 30-minute infusion; 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: 3-11.5 hours; 1 week to 1 month: 3 to 6 hours

Infants: 4 ± 1 hour

Children: 2 ± 1 hour

Adolescents: 1.5 ± 1 hour

Adults: 1.5-3 hours; End-stage renal disease: 36-70 hours

Protein Binding

<30%

Special Populations: Renal Function Impairment

Clearance is decreased in renal impairment.

Use: Labeled Indications

Treatment of susceptible bacterial infections, normally gram-negative organisms, including Pseudomonas, Proteus, Serratia, and gram-positive Staphylococcus; treatment of bone infections, respiratory tract infections, skin and soft tissue infections, as well as abdominal and urinary tract infections, and septicemia; treatment of infective endocarditis

Use: Unlabeled

Surgical (preoperative) prophylaxis

Contraindications

Hypersensitivity to gentamicin or other aminoglycosides

Dosing: Adult

Individualization is critical because of the low therapeutic index.

In underweight and nonobese patients, use of total body weight (TBW) instead of ideal body weight for determining the initial mg/kg/dose is widely accepted (Nicolau, 1995). Ideal body weight (IBW) also may be used to determine doses for patients who are neither underweight nor obese (Gilbert, 2009).

Initial and periodic plasma drug levels (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).

Usual dosage ranges:

IM, IV:

Conventional: 1-2.5 mg/kg/dose every 8-12 hours; to ensure adequate peak concentrations early in therapy, higher initial dosage may be considered in selected patients when extracellular water is increased (edema, septic shock, postsurgical, or trauma)

Once daily: 4-7 mg/kg/dose once daily; some clinicians recommend this approach for all patients with normal renal function; this dose is at least as efficacious with similar, if not less, toxicity than conventional dosing

Intrathecal: 4-8 mg/day

Indication-specific dosing: IM, IV:

Brucellosis: 240 mg (IM) daily or 5 mg/kg (IV) daily for 7 days; either regimen recommended in combination with doxycycline

Cholangitis: 4-6 mg/kg once daily with ampicillin

Diverticulitis (complicated): 1.5-2 mg/kg every 8 hours (with ampicillin and metronidazole)

Endocarditis, treatment:

Enterococcus (native or prosthetic valve) (off-label dose): IV, IM: 3 mg/kg/day in 2 or 3 divided doses in combination with a beta-lactam or vancomycin (choice of concomitant antibiotic and treatment duration are dependent on organism sensitivity testing and source of infection) (AHA [Baddour 2015])

S. aureus (prosthetic valve; methicillin-susceptible or methicillin-resistant) (off-label dose): IV, IM: 3 mg/kg/day in 2 or 3 divided doses for 2 weeks; use in combination with other antibiotics (choice of concomitant antibiotic dependent on organism sensitivity testing) (AHA [Baddour 2015])

Viridans group streptococcus (VGS) and S. bovis (native or prosthetic valve) (off-label dose): IV, IM: 3 mg/kg/day once daily (preferred) or in 3 divided doses (alternative) in combination with other antibiotics (choice of concomitant antibiotic and treatment duration are dependent on organism sensitivity testing and source of infection) (AHA [Baddour 2015])

Gonococcal infection, uncomplicated (patients with severe cephalosporin allergy) (off-label use): IM: 240 mg as a single dose in combination with oral azithromycin (CDC [Workowski 2015])

Granuloma inguinale (donovanosis) (off-label use): 1 mg/kg/dose every 8 hours; gentamicin must be used in addition to the recommended antibiotic agent and only if improvement is not evident within the first days of therapy (CDC [Workowski 2015])

Meningitis Enterococcus sp or Pseudomonas aeruginosa: IV: Loading dose 2 mg/kg, then 1.7 mg/kg/dose every 8 hours (administered with another bacteriocidal drug)

Pelvic inflammatory disease (off-label use) : Loading dose: 2 mg/kg IV or IM, then 1.5 mg/kg IV every 8 hours or 3 to 5 mg/kg IV once daily in combination with clindamycin IV. Transition from parenteral to oral therapy can usually be initiated within 24 to 48 hours of clinical improvement for a total treatment duration of 14 days (CDC [Workowski 2015])

Plague (Yersinia pestis): Treatment: 5 mg/kg/day, followed by postexposure prophylaxis with doxycycline

Pneumonia, hospital- or ventilator-associated: 7 mg/kg/day (with antipseudomonal beta-lactam or carbapenem)

Surgical (preoperative) prophylaxis (off-label use): IV: 5 mg/kg within 60 minutes prior to surgical incision with or without other antibiotics (procedure dependent). Note: Dose is based on actual body weight unless >20% above ideal body weight, then dosage requirement may best be estimated using a dosing weight of IBW + 0.4 (TBW - IBW) (Bratzler, 2013).

Synergy (for gram-positive infections): 3 mg/kg/day in 1-3 divided doses (with ampicillin)

Tularemia: 5 mg/kg/day divided every 8 hours for 1-2 weeks

Urinary tract infection: 1.5 mg/kg/dose every 8 hours

Dosing: Geriatric

Refer to adult dosing.

Dosing: Pediatric

Individualization is critical because of the low therapeutic index.

Use of ideal body weight (IBW) for determining the mg/kg/dose appears to be more accurate than dosing on the basis of total body weight (TBW).

Initial and periodic plasma drug levels (eg, peak and trough with conventional 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).

Usual dosage ranges: IM, IV:

Infants and Children <5 years: 2.5 mg/kg/dose every 8 hours*

Children ≥5 years: 2-2.5 mg/kg/dose every 8 hours*

*Note: Higher individual doses and/or more frequent intervals (eg, every 6 hours) may be required in selected clinical situations (cystic fibrosis) or serum levels document the need.

Surgical (preoperative) prophylaxis (off-label use): Children ≥1 year: IV: 2.5 mg/kg within 60 minutes prior to surgical incision with or without other antibiotics (procedure dependent). Note: Dose is based on actual body weight unless >20% above ideal body weight, then dosage requirement may best be estimated using a dosing weight of IBW + 0.4 (TBW - IBW) (Bratzler, 2013).

Dosing: Renal Impairment

Conventional dosing:

CrCl >60 mL/minute: Administer every 8 hours

CrCl 40 to 60 mL/minute: Administer every 12 hours

CrCl 20 to 39 mL/minute: Administer every 24 hours

CrCl <20 mL/minute: Loading dose, then monitor levels

High-dose therapy: Interval may be extended (eg, every 48 hours) in patients with moderate renal impairment (CrCl 30-59 mL/minute) and/or adjusted based on serum level determinations.

Intermittent hemodialysis (IHD) (administer after hemodialysis on dialysis days) (Heintz, 2009): Dialyzable (~50%; variable; dependent on filter, duration, and type of IHD):

Loading dose of 2-3 mg/kg loading dose followed by:

Mild UTI or synergy: 1 mg/kg every 48-72 hours; monitor levels

Moderate-to-severe UTI: 1-1.5 mg/kg every 48-72 hours; monitor levels

Systemic gram-negative rod infection: 1.5-2 mg/kg every 48-72 hours; monitor levels

Note: Dosing dependent on the assumption of 3 times/week, complete IHD sessions.

Peritoneal dialysis (PD):

Administration via PD fluid:

Gram-positive infection (eg, synergy): 3-4 mg/L (3-4 mcg/mL) of PD fluid

Gram-negative infection: 4-8 mg/L (4-8 mcg/mL) of PD fluid

Administration via IV, IM route during PD: Dose as for CrCl <10 mL/minute and follow levels

Continuous renal replacement therapy (CRRT) (Heintz, 2009; Trotman, 2005): Drug clearance is highly dependent on the method of renal replacement, filter type, and flow rate. Appropriate dosing requires close monitoring of pharmacologic response, signs of adverse reactions due to drug accumulation, as well as target drug concentrations (if appropriate). The following are general recommendations only (based on dialysate flow/ultrafiltration rates of 1-2 L/hour and minimal residual renal function) and should not supersede clinical judgment:

CVVH/CVVHD/CVVHDF: Loading dose of 2-3 mg/kg followed by:

Mild UTI or synergy: 1 mg/kg every 24-36 hours; monitor levels

Moderate-to-severe UTI: 1-1.5 mg/kg every 24-36 hours; monitor levels

Systemic gram-negative infection: 1.5-2.5 mg/kg every 24-48 hours; monitor levels

Dosing: Hepatic Impairment

Monitor plasma concentrations.

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).

Administration

IM: Administer by deep IM route if possible. Slower absorption and lower peak concentrations, probably due to poor circulation in the atrophic muscle, may occur following IM injection; in paralyzed patients, suggest IV route.

IV: Infuse over 30-120 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.

Dietary Considerations

Calcium, magnesium, potassium: Renal wasting may cause hypocalcemia, hypomagnesemia, and/or hypokalemia.

Compatibility

Stable in dextran 40, D5W, D10W, mannitol 20%, LR, NS; incompatible with fat emulsion 10%.

Y-site administration: Incompatible with allopurinol, amphotericin B cholesteryl sulfate complex, azithromycin, furosemide, hetastarch in NS, idarubicin, indomethacin, iodipamide meglumine, pemetrexed, propofol, warfarin.

Storage

Gentamicin is a colorless to slightly yellow solution which should be stored between 2°C to 30°C, but refrigeration is not recommended. IV infusion solutions mixed in NS or D5W solution are stable for 48 hours at room temperature and refrigeration (Goodwin, 1991). Premixed bag: Manufacturer expiration date; remove from overwrap stability: 30 days.

Drug Interactions

AbobotulinumtoxinA: Aminoglycosides may enhance the neuromuscular-blocking effect of AbobotulinumtoxinA. Monitor therapy

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

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

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. 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

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

OnabotulinumtoxinA: Aminoglycosides may enhance the neuromuscular-blocking effect of OnabotulinumtoxinA. 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; Cloxacillin; Dicloxacillin; Nafcillin; Oxacillin; Penicillin G (Parenteral/Aqueous); Penicillin G Benzathine; Penicillin G Procaine; Penicillin V Potassium. Consider therapy modification

RimabotulinumtoxinB: Aminoglycosides may enhance the neuromuscular-blocking effect of RimabotulinumtoxinB. Monitor therapy

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, Clostridium difficile-associated diarrhea, decreased appetite, enterocolitis, nausea, sialorrhea, stomatitis, vomiting

Genitourinary: Casts in urine (hyaline, granular), changes in distal tubules (dysfunction), 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 healthy 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 become 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. In the newborn infant, exchange transfusion may also be considered.

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, because 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:

• Nephrotoxicity: [U.S. Boxed Warning]: May cause nephrotoxicity; usual risk factors include pre-existing 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 muscle relaxants.

• Neurotoxicity: [U.S. Boxed Warning]: May cause neurotoxicity; usual risk factors include pre-existing 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 C. difficile-associated diarrhea (CDAD) and pseudomembranous colitis; CDAD has been observed >2 months postantibiotic treatment.

Disease-related concerns:

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

• Hypocalcemia: Use with caution in patients with hypocalcemia.

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

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

Other warnings/precautions:

• Long-term use: Not intended for long-term therapy due to toxic hazards associated with extended administration.

Monitoring Parameters

Urinalysis, urine output, BUN, serum creatinine, plasma gentamicin levels (as appropriate to dosing method). Levels are typically obtained 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

[US Boxed Warning]: Aminoglycosides may cause fetal harm if administered to a pregnant woman. Gentamicin crosses the placenta. 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

• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)

• Have patient report immediately to prescriber signs of kidney problems (urinary retention, blood in urine, change in amount of urine passed, weight gain), change in balance, severe dizziness, passing out, hearing loss, tinnitus, muscle weakness, burning or numbness feeling, twitching, seizures, shortness of breath, illogical thinking, depression, vision changes, or severe headache (HCAHPS).

• Educate patient about signs of a significant reaction (eg, 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. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for healthcare professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience and judgment in diagnosing, treating and advising patients.

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