INDICATIONS     CONTRA-INDICATIONS     DOSAGE     SIDE-EFFECTS     PREGNANCY     OVERDOSE     IDENTIFICATION     PATIENT INFORMATION
MICRO GENTAMICIN Injection 20 mg/2 mL
MICRO GENTAMICIN Injection 40 mg/1 mL
MICRO GENTAMICIN Injection 80 mg/2 mL

SCHEDULING STATUS:
S4

PROPRIETARY NAME
(and dosage form):

MICRO GENTAMICIN Injection 20 mg/2 mL
MICRO GENTAMICIN Injection 40 mg/1 mL
MICRO GENTAMICIN Injection 80 mg/2 mL

COMPOSITION:
Each 2 mL ampoule contains gentamicin sulphate equivalent to gentamicin base 20 mg/2 mL.
Each 1 mL ampoule contains gentamicin sulphate equivalent to gentamicin base 40 mg/1 mL.
Each 2 mL ampoule contains gentamicin sulphate equivalent to gentamicin base 80 mg/2 mL.

PHARMACOLOGICAL CLASSIFICATION:
A 20.1.1 Broad and medium spectrum antibiotics.

PHARMACOLOGICAL ACTION:
Gentamicin is an aminoglycoside antibiotic with in vitro bactericidal activity against Gram-negative organisms including strains of, Escherichia coli, Enterobacter, Klebsiella, Proteus and Pseudomonas species. In vitro sensitivity does not necessarily imply in vivo efficacy. With the exception of Staphylococcus aureus gentamicin sulphate is not active against gram-positive organisms. In the treatment of Staphylococcal infections gentamicin must be used in combination with other antibiotics. Gentamicin is absorbed rapidly when administered intramuscularly. It is excreted almost entirely by globular filtration.

INDICATIONS:
Gentamicin injection is indicated for the following conditions, when caused by susceptible organisms;

1.	Urinary tract infections; (Not indicated for the treatment of uncomplicated urinary tract infections).
2.	Systemic infections, e.g. Septicaemia, peritonitis;
3.	Bone and soft-tissue infections, e.g. osteomyelitis, wound and soft-tissue infections;
4.	Infected burns;
5.	Infections of the respiratory tract e.g. Pneumonia.

CONTRA-INDICATIONS:
Gentamicin is contra-indicated in patients with a known history of allergy to it. Aminoglycosides should be avoided in patients with myasthenia gravis.
Pregnancy and lactation.

WARNINGS:
Due to the risk of ototoxicity and neurotoxicity with prolonged use of aminoglycosides, gentamicin must be restricted to the therapy of life-threatening infections in which a less toxic antimicrobial agent is not suitable. Serum peak levels of 10 micrograms/mL must be avoided as this could be toxic. Serum trough levels of more than 2 micrograms /mL may be the best indication of accumulation of gentamicin which may be associated with toxicity.
To ensure safe and effective therapy, dosages should be monitored with serum peak and trough levels. Where practical, regular determination of plasma creatinine levels is advised.
Toxic levels may be reached when gentamicin is administered in normal doses to patients with impaired renal function.

DOSAGE AND DIRECTIONS FOR USE:
Intramuscular Administration:
Gentamicin Injection is usually administered intramuscularly. Intravenous administration should only be reserved for special cases. (Refer Intravenous Administration).
Adult patients with normal renal function:
3 mg to 5 mg/kg/day in 3 equal doses (8 hourly).
Children, infants and neonates:
Children:
A dose of 3 to 5 mg/kg/day is administered in three equally divided doses every 8 hours, depending on severity.
Neonates and infants less than 1 week:
6 mg/kg/day is administered in two divided doses every 12 hours.
Infants older than one week:
6 mg/kg/day administered in two equal doses every 12 hours, or three equally divided doses every 8 hours.
Intravenous Administration:
This route of administration is only recommended in special circumstances. Doses for administration are the same as those used intramuscularly. Intravenous administration may be infused over a period up to 2 hours. Dilutions of up to 160 mg per litre of Sodium Chloride 0.9% and or Dextrose 5% are compatible and may be used, within 24 hours of admixture.
Duration of Treatment:
The course of treatment should be limited to 7 to 10 days.
Patients with impaired renal function:
Dosage must be adjusted in patients with impaired renal function. To minimise risk of toxicity in these patients, the first dose should be that normally recommended. Subsequent doses should be administered less frequently depending on the degree of renal impairment. Since the serum half-life of gentamicin has a close correlation with creatine clearance and serum creatinine, the serum half-life (in hours) of gentamicin may be estimated by multiplying the serum creatinine (expressed in mg % ), by four. The interval between doses, in hours, may be approximated by doubling the serum half-life.
Table 1 provides the guidance for adjustment of the interval between doses of gentamicin based on the aforementioned renal function tests. In those instances when only a blood urea concentration is available, this value may be utilized initially; however, it should be supplemented with a serum creatinine level or creatinine clearance rate whenever possible.

Table 1:

		RENAL FUNCTION TEST
Body mass Adult Patient (Kg)	Dose (mg)		Creatinine Clearance Rate (mL/min)	Serum Creatinine (mg %)	Blood Urea (mg %)	Frequency of Administration
Over 60	80 (2 mL)		Over 70	Less than 1,4	Less than 38	Every 8 hours
			35 - 70	1,4 - 1,9	38 - 63		Every 12 hours
			24 - 34	2,0 - 2,8	64 - 84		Every 18 hours
			16 - 23	2,9 - 3,7	85 - 105		Every 24 hours
			10 - 15	3,8 - 5,3	106 - 159		Every 36 hours
			* 5 - 9	5,4 - 7,2	160 - 214		Every 48 hours
60 or less	1,5 mL		Same	as above

The above dosage schedule is not intended as a rigid recommendation.

*	It should be used in conjunction with close clinical and laboratory observations.
*	It should be used as a dosage guide when measurement of gentamicin serum levels is not feasible.
*	When the creatinine clearance level is less than 5 mL/min, then haemodialysis is indicated. Gentamicin is dialysable and the dose should be individually adapted to the patient after each period of dialysis.

SIDE-EFFECTS AND SPECIAL PRECAUTIONS:
It can produce irreversible, cumulative ototoxicity affecting both the cochlea (manifest as hearing loss of higher tones) and more common, the vestibular system (manifest as dizziness and vertigo). Concurrent use of an anti-emetic eg. dimenhydrinate may mask the early symptoms of vestibular ototoxicity.
Reversible nephrotoxicity may occur and acute renal failure has been reported, often in association with the concurrent administration of other nephrotoxic agents eg. other aminoglycosides, vancomycin, some cephalosporins, or potentially ototoxic agents such as ethacrynic acid and furosemide.
Renal impairment is usually mild, although acute tubular necrosis and interstitial nephritis have occurred. Decreased glomerular filtration rate is usually seen only after several days, and may even occur after therapy has been discontinued.
Aminoglycosides possess a neuromuscular blocking action and respiratory depression and muscular paralysis have been reported and care is required when another neuromuscular blocking agent is given concomitantly. Neurotoxicity has occurred, both peripheral neuropathies and central symptoms including encephalopathy, confusion, lethargy, hallucinations, convulsions and central depression.
Cross-sensitivity may occur between aminoglycosides. Hypersensitivity reactions, anaphylactic reactions and endotoxic shock has been reported.
Infrequent effects reported include blood dyscrasias, purpura, nausea and vomiting, stomatitis, and signs of liver dysfunction eg. increased serum aminotransferase values and increased serum - bilirubin concentrations. Great care is required in patients with myasthenia gravis, parkinsonism and other conditions characterised by muscle weakness. It is desirable to determine dosage requirements by individual monitoring. Dosage should be adjusted to avoid peak plasma concentrations above 10 to 20 micrograms/mL, or trough concentrations exceeding 2 micrograms/mL. Monitoring is important in patients receiving high doses or prolonged courses, in infants and the elderly and in patients with renal failure.
Use of aminoglycosides during pregnancy may damage the 8th cranial nerve of the foetus.

KNOWN SYMPTOMS OF OVERDOSAGE AND ITS TREATMENT:
Gentamicin serum-blood levels in excess of 12 micrograms/mL may result in ototoxicity in patients with renal impairment. This is reversible if timeously observed and the dose is suitable adjusted.
In the event of overdosage or toxic reactions, peritoneal dialysis or haemodialysis will aid in the removal of gentamicin from the blood.

IDENTIFICATION:
A clear, colourless to light yellow solution.

PRESENTATION:
2 mL clear colourless glass ampoules of 20 mg/2 mL packed in boxes of 10 and 100.
1 mL clear colourless glass ampoules of 40 mg/1 mL packed in boxes of 10 and 100.
2 mL clear colourless glass ampoules of 80 mg/2 mL packed in boxes of 10 and 100.

STORAGE INSTRUCTIONS:
Store below 25°C.
Keep out of reach of children.

REGISTRATION NUMBERS:
2 mL clear colourless glass ampoules of 20 mg/2 mL: 31/20.1.1/0441
1 mL clear colourless glass ampoules of 40 mg/1 mL: 31/20.1.1/0442
2 mL clear colourless glass ampoules of 80 mg/2 mL: 31/20.1.1/0443

NAME AND BUSINESS ADDRESS OF APPLICANT
Micro Healthcare (Pty) Ltd.
10 Lindley Street
BETHLEHEM
9701
South Africa

DATE OF PUBLICATION OF THIS PACKAGE INSERT:
February 1996

        PMI 1861/06-02

New addition to this site: September 2005
Source: Hospital Pharmacy
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