Amikacin Injection 500mg/2mL Description Amikacin is a semisynthetic aminoglycoside antibiotic derived from kanamycin. Amikacin occurs as a white, crystalline powder and is sparingly soluble in water. The injection consists of the sulfate salt. Amikacin Injection is a sterile clear, colourless solution, free from specks, lint, or other visible evidence of contamination. Each 2 mL vial contains amikacin sulfate equivalent to amikacin activity 500 mg (500,000 I.U.). Pharmacokinetics Absorption Following IM administration of a single dose of amikacin of 7.5 mg/kg in adults with normal renal function, peak plasma amikacin concentrations of 17-25 micrograms/mL are attained within 45 minutes to 2 hours. Following IV infusion of the same dose given over 1 hour peak plasma concentrations of the drug average 38 micrograms/mL immediately following the infusion, 5.5 micrograms/mL at 4 hours, and 1.3 micrograms/mL at 8 hours. Distribution Following administration of usual dosages of amikacin, amikacin has been found in bone, heart, gallbladder, and lung tissue. Amikacin is also distributed into bile, sputum, bronchial secretions, and interstitial, pleural, and synovial fluids. Elimination The plasma elimination half-life of amikacin is usually 2-3 hours in adults with normal renal function and is reported to range from 30-86 hours in adults with severe renal impairment. In adults with normal renal function, 94-98% of a single IM or IV dose of amikacin is excreted unchanged by glomerular filtration within 24 hours. The drug may be completely recovered within approximately 10-20 days in patients with normal renal function. Terminal elimination half-lives of greater than 100 hours have been reported in adults with normal renal function following repeated IM or IV administration of the drug. In patients with impaired renal function, the clearance of amikacin is decreased; the more severe the impairment, the slower the clearance. Therefore, the interval between doses should be adjusted according to the degree of renal impairment. Endogenous creatinine clearance rate and serum creatinine which have high correlation with serum half-life of amikacin, may be used as a guide for this purpose (see Dossge and Administration - Impaired Renal Function). Indications Amikacin Injection is indicated in the short-term treatment of serious infections caused by susceptible strains of Gramnegative bacteria, (see Microbiology). Staphylococcus aureus, including methicillin-resistant strains is the principal Gram-positive organism sensitive to amikacin. The use of amikacin in the treatment of staphylococcal infections should be restricted to second-line therapy, and should be confined to patients suffering from severe infections caused by susceptible strains of stapylococcus who have failed to respond or are allergic to other available antibiotics. Amikacin Injection is indicated in the treatment of neonatal sepsis when sensitivity testing indicates that other aminoglycosides cannot be used. In certain severe infections such as neonatal sepsis, concomitant therapy with a penicillin type drug may be indicated because of the possibility of infections due to Gram-positive organisms such as streptococci or pneumococci. If concomitant treatment with a penicillin type drug is indicated, then the drugs should be administered separately and at different sites because in-vitro mixing of the two drugs causes inactivation of amikacin. Clinical studies have shown amikacin to be effective in treating bacteraemia, septicaemia including neonatal sepsis and serious infections of the respiratory tract, bones and joints, central nervous system, skin and skin structures (including those resulting from burns), intra-abdominal organs, post-operative infections and complicated and recurrent urinary tract infections, when caused by susceptible organisms.
Contraindications Amikacin Injection is contraindicated in patients with a known history of hypersensitivity to amikacin, any constituents of the injection (see Description ) or in patients who may have subclinical renal or eighth nerve damage induced by prior administration of nephrotoxic and/or ototoxic agents, as the toxicity may possibly be additive. Pregnancy (see Use in Pregnancy) ; Lactation (see, Use in Lactation). Use in Pregnancy Category D. Gentamicin and other aminoglycosides cross the placenta. There is evidence of selective uptake of gentamicin by the foetal kidney resulting in dam ge (probably reversible) to immature nephrons, eighth cranial nerve damage has also been reported following in-utero exposure to some of the aminoglycosides. Because of the chemical similarity, all aminoglycosides must be considered potentially nephrotoxic and ototoxic to the foetus. It should also be noted that therapeutic blood levels in the mother do not equate with safety for the foetus. Use in Lactation It is not known whether amikacin is excreted in breast milk. Since the possible harmful effect on the infant is not known, it is recommended that if nursing mothers must be given amikacin, the infants should not be breast fed during therapy. Interactions with Other Drugs If possible, do not give amikacin in conjunction with athacrynic acid, frusemide or other potent diuretics which may themselves cause ototoxicity or enhance aminoglycoside toxicity by altering antibiotic concentrations in serum and tissue. Potent diuretics: Other neurotoxic and/or nephrotoxic agents: If possible, avoid concurrent or sequential use of other neurotoxic and/or nephrotoxic antibiotics, including other aminoglycosides, polymyxin B, colistin, cisplatin, vancomycin, amphotericin B, clindamycin and cephalosporins. Anaesthetics/neuromuscular blocking agents or medications with neuromuscular blocking activity: Concurrent use of amikacin with agents with neuromuscular blocking activity e.g. succinylcholine, tubocurarine, decamethonium, halogenated hydrocarbon inhalation anaesthetics, opioid analgesics and massive transfusions with citrated anticoagulated blood, should be carefully monitored; neuromuscular blockade may be enhanced, resulting in skeletal muscle weakness and respiratory depression or paralysisi (apnea); caution is recommended when these medications and amikacin are used concurrently during surgery or in the postoperative period, especially if there is a possibility of incomplete reversal of neuromuscular blockade postoperatively; treatment with anticholinesterase agents or calcium salts may help to reverse the blockade. Penicillins: Aminoglycosides are inactivated by solutions containing penicillins. This inactivation is brought about by the opening of the beta-lactam ring and combination of the penicillin with an amino group of the aminoglycoside to form a biologically inactive amide. For this reason, amikacin and penicillins should not be combined in intravenous injections/infusions. The inactivation of some aminoglycosides by penicillins has been reported in vivo, especially in patients with renal failure who maintain a higher level of the penicillin for a longer period of time compared to patients with normal renal function. Therefore, when amikacin and penicillins are used together in patients with renal failure, the time of administration of each drug should be staggered so that several hours separate each infusion. Compatibilities Amikacin sulfate is stable for 24 hours at room temperature in the presence of light at 5 mg/mL and 0.25 mg/mL in 0.9% Sodium Chloride Intravenous Infusion B.P. and 5% Glucose Intravenous Infusion B.P. solutions. Adverse Reactions Amikacin induced hepatotoxicity is not a common side effect, however it may occur. Increased serum transaminases (ALT, AST) increased serum bilirubin, hepatomegaly, and hepatic necrosis have been reported. The percentages below refer to incidence in clinical trials. Dosage and Administration Uncomplicated infections due to sensitive organisms should respond to treatment within 24 to 48 hours at the recommended dosage. If no improvement occurs within three to five days, the use of amikacin sulfate should be reeveluated and consideration be given to alternative therapy. Failure of the infection to respond may be due to resistance of the organism or to the presence of septic foci requiring surgical drainage. Whenever possible, and especially in patients with impaired renal function, peak and trough amikacin serum concentrations should be determined and dosage adjusted where necessary to maintain desired serum concentrations. In general, desired peak cone ntrations are between 15 to 30 micrograms/e mL, and trough concentrations should not exceed 5 to 10 micrograms/mL. An increased risk of toxicity may be associated with prolonged peak amikacin serum concentrations greater than 30 to 35 micrograms/mL. Intramuscular or Intravenous Administration The intramuscular route is preferred for most infections, but in life-threatening infections or when an intramuscular injection is not feasible, an intravenous infusion (0.25% over 30 to 60 minutes) may be used. The compatible diluents for intravenous use if required are as follows: 5% Glucose Intravenous Infusion B.P. in Water for Injections B.P. and Sodium Chloride Intravenous Infusion B.P. (0.9%). Use solutions for I.V. administration within 12 hours after preparation. Dosage Dosage of amikacin sulfate is expressed in terms of amikacin and calculated on a body weight basis. Dosage is identical for both routes of administration. The usual recommended dose of amikacin is 15mg/kg daily given in two or three equally divided doses. Dosage given for patients with normal renal function. Initiate treatment with a loading dose of 10 mg/kg followed by 7.5 mg/kg every 12 hours. The maximum total daily dose should not exceed 15 mg/kg. Solution infusions via the I.V. route should be given over a 1 to 2 hour period. Insufficient clinical use has not enabled firm dosage guidelines to be established for the use of amikacin in premature infants. Adults and Children: Neonates and Premature Infants: Overdosage Management In the event of overdosage or toxic reactions peritoneal dialysis or haemodialysis should be conside ed. These procedures are of particular importance in patients with impaired renal function. In the newborn infant, exchange transfusion may also be considered. Clinical features Likely signs and symptoms include tinnitus, vertigo, reversible or irreversible deafness, skin rash, drug fever, headache, paraesthesia, reduced renal function or renal failure.