DrugindexOnline^{2nd edition}

Pronouncation: (am-ih-KAE-sin SULL-fate)
Class: Aminoglycoside, parenteral

Trade Names:
Amikin
- Injection 250 mg/mL
- Pediatric injection 50 mg/mL

Mechanism of Action

Pharmacology

Inhibits production of bacterial protein, causing bacterial cell death.

Pharmacokinetics

Absorption

IM

Rapidly absorbed. C _max is 12 to 21 mcg/mL (250 to 500 mg doses). T _max is 1 h.

IV

Single doses (500 mg over 30 min) produced C _max 38 mcg/mL.

Distribution

Vd is 24 L and protein binding is 0% to 11%. Crosses the placenta.

Elimination

IM

98.2% is excreted in the urine as unchanged drug within 24 h.

IV

94% is excreted in the urine within 24 h. T _1/2 is about 2 h. Serum Cl is 100 mL/min; renal Cl is 94 mL/min.

Special Populations

Renal Function Impairment

Rate of excretion is decreased and t _1/2 is prolonged. Dosage adjustment may be needed.

Indications and Usage

Treatment of infections caused by susceptible strains of microorganisms, especially gram-negative bacteria.

Contraindications

Generally not indicated for long-term therapy because of ototoxicity and nephrotoxicity.

Dosage and Administration

Adults, Children, and Infants

IV/IM 15 mg/kg (ideal body weight)/day in 2 or 3 divided doses. Treatment in heavier patients should not exceed 1.5 g/day.

Uncomplicated utis

IV/IM 250 mg twice daily.

Newborns

IV/IM Loading dose of 10 mg/kg is recommended followed by 7.5 mg/kg q 12 h. Lower doses may be needed in first 2 wk of life.

Storage/Stability

Store at 20° to 25°C (68° to 77°F).

Drug Interactions

Drugs with nephrotoxic potential (eg, cephalosporins, enflurane, methoxyflurane, vancomycin)

May increase risk of nephrotoxicity.

Loop diuretics (eg, furosemide)

May increase risk of auditory toxicity.

Neuromuscular blocking agents (eg, tubocurarine)

Amikacin may enhance effects of these agents.

Incompatibility

Do not mix with betalactam antibiotics (eg, carbenicillin, ticarcillin).

Laboratory Test Interactions

None well documented.

Adverse Reactions

EENT

Hearing loss; deafness; loss of balance.

Genitourinary

Oliguria; proteinuria; increased serum creatinine; urinary casts; red and white blood cells in urine; azotemia.

Miscellaneous

Decreased serum magnesium.

Precautions

Warnings Neurotoxicity Manifests as both auditory and vestibular ototoxicity, and primarily occurs in patients with pre-existing renal damage or with prolonged therapy. Partial or total irreversible deafness may continue to develop after drug is stopped. Other features of neurotoxicity include paresthesias, twitching, and seizures. Nephrotoxicity Usually reversible. Teratogenic in pregnancy. Renal and eighth nerve function closely monitored in patients with suspected renal dysfunction. Monitor peak and trough concentrations. Dosage adjustments required in renal function impairment. Neuromuscular blockade and respiratory paralysis have been reported following use of aminoglycosides. The possibility of these phenomena should be considered if aminoglycosides are administered by any route, especially in patients receiving anesthetics; neuromuscular blocking agents or in patients receiving massive transfusions of citrate-anticoagulated blood.

Pregnancy

Category D .

Lactation

Undetermined.

Children

Cautious use is necessary in premature infants and newborns because of renal immaturity.

Renal Function

Dosage adjustment is needed in patients with this condition.

Patient Information

• Encourage patient to increase fluid intake to 2,000 to 3,000 mL/day, unless contraindicated.
• Warn patient that diarrhea and abdominal bloating are common side effects of antibiotics.
• Inform patient that improvement should be seen in 3 to 5 days.
• Instruct patient to report the following signs to health care provider: Hypersensitivity, tinnitus, vertigo, hearing loss.
• Teach patient to look for signs of renal failure and to notify health care provider immediately if these signs occur.