Pharmacology: Intramuscular Administration: Amikacin is rapidly absorbed after intramuscular administration. In normal adult volunteers, average peak serum concentrations of about 12, 16 and 21 μg/ml are obtained 1 hour after intramuscular administration of 250 mg (3.7 mg/kg), 375 mg (5 mg/kg), 500 mg (7.5 mg/kg), single doses, respectively.
At 10 hours, serum levels are about 0.3 μg/ml, 12 μg/ml and 21 μg/ml, respectively. Tolerance studies in normal volunteers reveal that amikacin is well tolerated locally following repeated intramuscular dosing, and when given at maximally recommended doses, no ototoxicity or nephrotoxicity has been reported. There is no evidence of drug accumulation with repeated dosing for 10 days when administered according to recommended doses.
Intravenous Administration: Single doses of 500 mg (7.5 mg/kg) administered to normal adults as an infusion over a period of 30 minutes produced a mean peak serum concentration of 38 μg/ml at the end of the infusion. 84% of the administered dose was excreted in the urine in 9 hours and about 94% within 24 hours.
Repeat infusions of 7.5 mg/kg every 12 hours in normal adults were well tolerated and caused no drug accumulation.
General: Following administration at the recommended dose, therapeutic levels are found in bone, heart, gallbladder and lung tissue in addition to significant concentrations in urine; bile; sputum; bronchial secretions; interstitial, pleural and synovial fluids.
Spinal fluid levels in normal infants are approximately 10 to 20% of the serum concentrations and may reach 50% when the meninges are inflamed.