Gentamicin injetions

Drug Class Description :
Aminoglycosides.
Drug description :
1 ml of solution for injection contains 40 mg of gentamicin (as sulphate) 1 vial of 2 ml solution for injection contains 80 mg of gentamicin (as sulphate)
Presentation :
Solution for injection. Vials containing a clear colourless solution.
Indications :
Gentamicin is bactericidal and is active against many strains of Gram-positive and Gram-negative pathogens including species of Escherichia, Enterobacter, Klebsiella, Salmonella, Serratia, Shigella, Staphylococcus aureus, some Proteus and against Pseudomonas aeruginosa. Gentamicin is often effective against strains of these organisms which are resistant to other antibiotics such as streptomycin, kanamycin and neomycin. Gentamicin is effective against penicillin-resistant Staphylococci, but rarely effective against Streptococci. Gentamicin is indicated in the treatment of the following infections when caused by susceptible organisms. Severe Gram-Negative Infections: Upper and lower urinary tract infections Burn and wound infections Septicaemia, Bacteraemia Abscesses Subacute Bacterial Endocarditis Respiratory Tract infections (Bronchopneumonia) Neonatal infections Gynaecological infections Gram-Positive Infections: Bacteraemia Abscesses Accidental and operative trauma Burns and serious skin lesions.
Adult Dosage:
Gentamicin is normally given by the intramuscular route, but can be given intravenously when intramuscular administration is not feasible.
Gentamicin is normally given by the intramuscular route, but can be given intravenously when intramuscular administration is not feasible, e.g. in shocked or severely burned patients. When given intravenously, the prescribed dose should be administered slowly over 2 to 3 minutes directly into a vein or into the rubber tubing of a giving set. Rapid, direct intravenous administration may give rise, initially, to potentially neurotoxic concentrations and it is essential that the prescribed dose is administered over the recommended period of time. Alternatively the prescribed dose should be dissolved in up to 100 ml of normal saline or 5% glucose in water, but not solutions containing bicarbonate (see Incompatibilities P6B, 7h), and the solution infused over a period of 20 to 30 minutes.
The same dosage schedule is recommended for intramuscular and intravenous dosing. Dosage is related to the severity of infection, the age of the patient and the patient's renal function.
The daily dose recommended in children, adolescents and adults with normal renal function, is 3-6 mg/kg body weight per day as 1 (preferred) up to 2 single doses.
The daily dose in infants after the first month of life is 4.5-7.5 mg/kg body weight per day as 1 (preferred) up to 2 single doses.
The daily dose in newborns is 4-7 mg/kg body weight per day. Due to the longer half-life, newborns are given the required daily dose in 1 single dose.
In impaired renal function, the recommended daily dose has to be decreased and adjusted to the renal function.
Monitoring advice:
Serum concentration monitoring of gentamicin is recommended, especially in elderly, in newborns and in patients with impaired renal function. Samples are taken at the end of a dosing interval (trough level). Trough levels should not exceed 2 µg/ml administering gentamicin twice daily and 1 µg/ml for a once daily dose
Child Dosage :
Up to two weeks, 3mg/kg every 12 hours; two weeks to 12 years, 2mg/kg every eight hours. Contra Indications:
Patients being treated with gentamicin should be under close clinical observation because of its potential toxicity. There are no absolute contraindications other than a history of hypersensitivity to gentamicin. Gentamicin should be used with caution in premature infants because of their renal immaturity, in elderly people and generally in patients with impaired renal function. Diabetes, auditory vestibular dysfunctions, otitis media, a history of otitis media, previous use of ototoxic drugs and a genetically determined high sensitivity to aminoglycoside induced ototoxicity, are other main factors which may pre-dispose the patient to toxicity.
Special Precautions:
As with other aminoglycosides toxicity is related to serum concentration. At serum levels more than 10 micrograms/ml the vestibular mechanism may be affected. Toxicity can be minimised by monitoring serum concentrations and it is advisable to check serum levels to confirm that peak levels (one hour) do not exceed 10 micrograms/ml and that trough levels (one hour before next injection) do not exceed 2 micrograms/ml. Evidence of toxicity requires adjustment of dosage or withdrawal of the drug.
Concurrent use of other neurotoxic and/or nephrotoxic drugs can increase the possibility of gentamicin toxicity. Co-administration with the following agents should be avoided:
Neuromuscular blocking agents such as succinylcholine and tubocurarine.Other potentially nephrotoxic or ototoxic drugs such as cephalosporins and methicillin.Potent diuretics such as ethacrynic acid and furosemide.Other aminoglycosides.
To avoid adverse events, continuous monitoring (before, during and after) of renal function (serum creatinin, creatinin clearance), control of function of vestibule and cochlea as well as hepatic and laboratory parameters is recommended.
Interactions:
Antibacterials: increased risk of nephrotoxicity with cephalosporins notably cephalothin .
Gentamicin has been known to potentiate anticoagulants such as warfarin and phenindione.
Antifungals: increased risk of nephrotoxicity with amphotericin.
Cholinergics: antagonism of effect of neostigmine and pyridostigmine.
Cyclosporin: increased risk of nephrotoxicity.
Cytotoxics: increased risk of nephrotoxicity and possible risk of ototoxicity with cisplatin.
Diuretics: increased risk of ototoxicity with loop diuretics.
Muscle relaxants: effect of non-depolarising muscle relaxants such as tubocurarine enhanced.
Adverse Reactions:
Ototoxicity and nephrotoxicity are the most common side effects associated with gentamicin therapy. Both effects are related to renal impairment and hence the dosage in such patients should be altered as suggested.
Other adverse reactions associated with gentamicin therapy include nausea, vomiting, urticaria, reversible granulocytopenia, allergic contact sensitization and neuromuscular blockade