Source: Medicines & Healthcare Products Regulatory Agency (GB) Revision Year: 2018 Publisher: Hospira UK Limited, Horizon, Honey Lane, Hurley, Maidenhead, SL6 6RJ, United Kingdom
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.
Consideration should be given to official local guidance on the appropriate use of antibacterial agents
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
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 no less than 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 no longer than 20 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.
Dosage is adjusted for patients with renal impairment to minimise the risk of toxicity. The first dose should be as normal – after this, doses should be given less frequently, the interval being determined by results of renal function tests as below.
Renal Function Tests:
| Blood Urea (mg/100 ml) | (mmol/l) | Creatinine Clearance (GFR) (ml/min) | Dose and frequency of administration |
|---|---|---|---|
| <40 | 6-7 | >70 | 80 mg* 8-hourly |
| 40-100 | 6-17 | 30-70 | 80 mg* 12-hourly |
| 100-200 | 17-34 | 10-30 | 80 mg* daily |
| >200 | >34 | 5-10 | 80 mg* every 48 hours |
| Twice weekly intermittent haemodialysis | <5 | 80 mg* after dialysis |
* 60 mg if body weight <60 kg. Frequency of dosage in hours may also be approximated as serum creatinine (mg%) x eight or in SI units, as serum creatinine (µmol/l) divided by 11. If these dosage guides are used, peak serum levels must be measured. Peak levels of gentamicin occur approximately one hour after intra muscular injection and intravenous injection. Trough levels are measured just prior to the next injection. Assay of peak serum levels gives confirmation of adequacy of dosage and also serves to detect levels above 10 mg/l, at which the possibility of ototoxicity should be considered. One hour concentrations of gentamicin should not exceed 10 mg/l (but should reach 4 mg/l), while the pre-dose trough concentration should be less than 2 mg/l.
The recommended dose and precautions for intramuscular and intravenous administration are identical. Gentamicin when given intravenously should be injected directly into a vein or into the drip set tubing over no less than three minutes. If administered by infusion, this should be over no longer than 20 minutes and in no greater volume of fluid than 100 ml.
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. Please refer to section 4.4.
As in the case of other aminoglycosides, toxicity is associated with serum levels above a critical value. In patients with normal renal function it is unlikely that toxic serum levels (in excess of 10 micrograms/ml) will be reached after administration of recommended doses. Where higher levels occur because of renal impairment, dosage should be reduced. In the event of an overdose or toxic reaction, peritoneal dialysis or haemodialysis will lower serum gentamicin levels. Calcium salts given intravenously have been used to counter the neuromuscular blockade caused by gentamicin.
Shelf life: 36 months.
Do not store above 25°C.
80 mg/2 ml: Clear, Type I glass vials in packs of 5 vials.
Not applicable.
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