Yes

Antibiotic, Aminoglycoside; Antibiotic, Ophthalmic; Antibiotic, Topical

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, endocarditis, and septicemia; used topically to treat superficial infections of the skin or ophthalmic infections caused by susceptible bacteria; prevention of bacterial endocarditis prior to dental or surgical procedures

C

Hypersensitivity to gentamicin or other aminoglycosides

Not intended for long-term therapy due to toxic hazards associated with extended administration; pre-existing renal insufficiency, vestibular or cochlear impairment, myasthenia gravis, hypocalcemia, conditions which depress neuromuscular transmission

>10%:

Central nervous system: Neurotoxicity (vertigo, ataxia)

Neuromuscular & skeletal: Gait instability

Otic: Ototoxicity (auditory), ototoxicity (vestibular)

Renal: Nephrotoxicity, decreased creatinine clearance

1% to 10%:

Cardiovascular: Edema

Dermatologic: Skin itching, reddening of skin, rash

<1%: Drowsiness, headache, pseudomotor cerebri, photosensitivity, erythema, anorexia, nausea, vomiting, weight loss, increased salivation, enterocolitis, granulocytopenia, agranulocytosis, thrombocytopenia, elevated LFTs, burning, stinging, tremors, muscle cramps, weakness, dyspnea

Symptoms of overdose include ototoxicity, nephrotoxicity, and neuromuscular toxicity; serum level monitoring is recommended

The treatment of choice, following a single acute overdose, appears to be the maintenance of good urine output of at least 3 mL/kg/hour. Dialysis is of questionable value in the enhancement of aminoglycoside elimination. If required, hemodialysis is preferred over peritoneal dialysis in patients with normal renal function. Careful hydration may be all that is required to promote diuresis and therefore the enhancement of the drug's elimination. Chelation with penicillins is experimental.

Increased toxicity:

Neuromuscular blocking agents may increase neuromuscular blockade

Gentamicin is a colorless to slightly yellow solution which should be stored between 2°C to 30°C, but refrigeration is not recommended

I.V. infusion solutions mixed in NS or D₅W solution are stable for 24 hours at room temperature and refrigeration

Premixed bag: Manufacturer expiration date

Out of overwrap stability: 30 days

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

Absorption: Oral: Not absorbed

Distribution: Crosses the placenta

V_d: Increased by edema, ascites, fluid overload; decreased in patients with dehydration

Neonates: 0.4-0.6 L/kg

Children: 0.3-0.35 L/kg

Adults: 0.2-0.3 L/kg

Relative diffusion of antimicrobial agents from blood into cerebrospinal fluid (CSF): Minimal even with inflammation

Ratio of CSF to blood level (%): Normal meninges: Nil; Inflamed meninges: 10-30

Protein binding: <30%

Half-life:

Infants: <1 week: 3-11.5 hours; 1 week to 6 months: 3-3.5 hours

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

Time to peak serum concentration: I.M.: Within 30-90 minutes; I.V.: 30 minutes after a 30-minute infusion

Elimination: Clearance is directly related to renal function, eliminated almost completely by glomerular filtration of unchanged drug with excretion into the urine

Individualization is critical because of the low therapeutic index

In morbid obesity, dosage requirement may best be estimated using a dosing weight of IBW + 0.4 (TBW - IBW)

Initial and periodic peak and trough plasma drug levels 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)

Newborns: Intrathecal: 1 mg every day

Infants >3 months: Intrathecal: 1-2 mg/day

Infants and Children <5 years: I.M., I.V.: 2.5 mg/kg/dose every 8 hours*

Cystic fibrosis: 2.5 mg/kg/dose every 6 hours

Children >5 years: I.M., I.V.: 1.5-2.5 mg/kg/dose every 8 hours*

Prevention of bacterial endocarditis: Dental, oral, upper respiratory procedures, GI/GU procedures: 2 mg/kg with ampicillin (50 mg/kg) 30 minutes prior to procedure

*Some patients may require larger or more frequent doses (eg, every 6 hours) if serum levels document the need (ie, cystic fibrosis or febrile granulocytopenic patients)

Adults: I.M., I.V.:

Severe life-threatening infections: 2-2.5 mg/kg/dose

Urinary tract infections: 1.5 mg/kg/dose

Synergy (for gram-positive infections): 1 mg/kg/dose

Prevention of bacterial endocarditis:

Dental, oral, or upper respiratory procedures: 1.5 mg/kg not to exceed 80 mg with ampicillin (1-2 g) 30 minutes prior to procedure

GI/GU surgery: 1.5 mg/kg not to exceed 80 mg with ampicillin 2 g 30 minutes prior to procedure

Children and Adults:

Intrathecal: 4-8 mg/day

Ophthalmic:

Ointment: Instill 1/2 " (1.25 cm) 2-3 times/day to every 3-4 hours

Solution: Instill 1-2 drops every 2-4 hours, up to 2 drops every hour for severe infections

Topical: Apply 3-4 times/day to affected area

Some clinicians suggest a daily dose of 4-7 mg/kg for all patients with normal renal function. This dose is at least as efficacious with similar, if not less, toxicity than conventional dosing.

Dosing interval in renal impairment:

Cl_cr greater than or equal to 60 mL/minute: Administer every 8 hours

Cl_cr 40-60 mL/minute: Administer every 12 hours

Cl_cr 20-40 mL/minute: Administer every 24 hours

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

Hemodialysis: Dialyzable; removal by hemodialysis: 30% removal of aminoglycosides occurs during 4 hours of HD; administer dose after dialysis and follow levels

Removal by continuous ambulatory peritoneal dialysis (CAPD):

Administration via CAPD fluid:

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

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

Administration via I.V., I.M. route during CAPD: Dose as for Cl_cr <10 mL/minute and follow levels

Removal via continuous arteriovenous or venovenous hemofiltration (CAVH/CAVHD): Dose as for Cl_cr 10-40 mL/minute and follow levels

Dosing adjustment/comments in hepatic disease: Monitor plasma concentrations

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

Urinalysis, urine output, BUN, serum creatinine; 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)

Timing of serum samples: Draw peak 30 minutes after 30-minute infusion has been completed or 1 hour after I.M. injection; draw trough immediately before next dose

Sample size: 0.5-2 mL blood (red top tube) or 0.1-1 mL serum (separated)

Therapeutic levels:

Peak:

Serious infections: 6-8 mg/mL (12-17 mmol/L)

Life-threatening infections: 8-10 mg/mL (17-21 mmol/L)

Urinary tract infections: 4-6 mg/mL

Synergy against gram-positive organisms: 3-5 mg/mL

Trough:

Serious infections: 0.5-1 mg/mL

Life-threatening infections: 1-2 mg/mL

Obtain drug levels after the third dose unless renal dysfunction/toxicity suspected

Penicillin may decrease aminoglycoside serum concentrations in vitro

Dizziness is common; may cause drowsiness

May rarely cause agranulocytosis; use caution with clozapine and carbamazepine

No information available to require special precautions

Increased salivation has been reported

Take exactly as directed and when prescribed. Drink adequate amounts of water (2-3 L/day of fluids unless instructed to restrict fluid intake). You may experience headaches, ringing in ears, dizziness, blurred vision (use caution when driving or engaging in tasks requiring alertness until response to drug is known); GI upset, loss of appetite (small frequent meals and frequent mouth care may help); photosensitivity (use sunscreen wear protective clothing and eyewear, and avoid direct sunlight). Report severe headache, changes in hearing acuity or ringing in ears, changes in urine pattern, difficulty breathing, rash, fever, unhealed sores, sores in mouth, vaginal drainage, muscle or bone pain, change in gait, or worsening of condition. Pregnancy/breast-feeding precautions: Inform prescriber if you are or intend to be pregnant. Consult prescriber if breast-feeding.

Topical: Apply thin film of ointment to affected area as often as recommended. May apply porous dressing. Report persistent burning, swelling, itching, worsening of condition, or lack of response to therapy.

Slower absorption and lower peak concentrations probably due to poor circulation in the atrophic muscle, may occur following I.M. injection in paralyzed patients (suggest I.V. route); aminoglycoside levels measured in blood taken from Silastic® central catheters can sometimes give falsely high readings (draw via separate lumen or peripheral site if possible, otherwise flush very well). Monitor serum creatinine and urine output; obtain drug levels after the third dose unless otherwise directed (eg, suspected toxicity or renal dysfunction). Peak levels are drawn 30 minutes after the end of a 30-minute infusion or 60 minutes following I.M. injection; trough levels are drawn within 30 minutes before the next dose; administer other antibiotic drugs at least 1 hour before or after gentamicin. Hearing should be tested before, during, and after treatment in patients at risk for ototoxicity.

Cream, topical, as sulfate (Garamycin®, G-myticin®): 0.1% (15 g)

Infusion, in D₅W, as sulfate: 60 mg, 80 mg, 100 mg

Infusion, in NS, as sulfate: 40 mg, 60 mg, 80 mg, 90 mg, 100 mg, 120 mg

Injection, as sulfate: 40 mg/mL (1 mL, 1.5 mL, 2 mL)

Pediatric, as sulfate: 10 mg/mL (2 mL)

Intrathecal, preservative free, as sulfate (Garamycin®): 2 mg/mL (2 mL)

Ointment, as sulfate:

Ophthalmic: 0.3% [3 mg/g] (3.5 g)

Garamycin®, Genoptic® S.O.P., Gentacidin®, Gentak®: 0.3% [3 mg/g] (3.5 g)

Topical, as sulfate (Garamycin®, G-myticin®): 0.1% (15 g)

Solution, ophthalmic, as sulfate: 0.3% (5 mL, 15 mL)

Garamycin®, Genoptic®, Gentacidin®, Gentak®: 0.3% (1 mL, 5 mL, 15 mL)

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