This information is intended for use by health professionals

1. Name of the medicinal product

Gentamicin Intrathecal 5mg/ml Solution for Injection.

2. Qualitative and quantitative composition

Each ampoule (1ml) contains Gentamicin Sulphate Ph Eur equivalent to 5mg Gentamicin base.

3. Pharmaceutical form

Injection.

4. Clinical particulars
4.1 Therapeutic indications

Gentamicin is an aminoglycoside antibiotic with broad-spectrum bactericidal activity. It is usually active against most strains of the following organisms: Escherichia coli, Klebsiella spp., Proteus spp. (indole positive and indole negative), Pseudomonas aeruginosa, Staphylococci, Enterobacter spp., Citrobacter spp. and Providencia spp.

Gentamicin Intrathecal Injection is indicated as a supplement to systemic therapy in bacterial meningitis, ventriculitis and other bacterial infections of the central nervous system.

4.2 Posology and method of administration

Bacterial meningitis and ventriculitis:

The starting dose of Gentamicin Intrathecal Injection for both children and adults is 1mg daily, intrathecally or intraventricularly, together with 1mg/kg every eight hours intramuscularly.

The MIC of the infecting organism in the C.S.F. should be assessed and, if necessary, the intrathecal/intraventricular dose increased to 5mg daily, whilst keeping the intramuscular dose at 1mg/kg eight-hourly.

Treatment should be continued for at least 7 days but longer if necessary.

Periodic serum and C.S.F. gentamicin assays should be carried out to ensure that adequate antibiotic levels are maintained and that serum and C.S.F. levels do not exceed 10mg/l.

Route of Administration

Intrathecal or intraventricular.

4.3 Contraindications

Gentamicin is contra-indicated in patients with a known allergy to it and other aminoglycosides. Evidence exists that gentamicin may cause neuromuscular blockade and is therefore contra-indicated in myasthenia gravis and related conditions.

4.4 Special warnings and precautions for use

Ototoxicity has been recorded following the use of gentamicin. Groups at special risk include patients with impaired renal function and possibly the elderly. Consequently, renal, auditory and vestibular functions should be monitored in these patients and serum levels determined so as to avoid peak concentrations above 10mg/l and troughs above 2mg/l. As there is some evidence that risk of both ototoxicity and nephrotoxicity is related to the level of total exposure, duration of therapy should be the shortest possible compatible with clinical recovery. In some patients with impaired renal function there has been a transient rise in blood-urea-nitrogen which has usually reverted to normal during or following cessation of therapy. It is important to adjust the frequency of dosage according to the degree of renal function.

4.5 Interaction with other medicinal products and other forms of interaction

Concurrent administration of gentamicin and other potentially ototoxic or nephrotoxic drugs should be avoided. Potent diuretics such as etacrynic acid and furosemide are believed to enhance the risk of ototoxicity whilst amphotericin B, cisplatin and ciclosporin are potential enhancers of nephrotoxicity.

Any potential nephrotoxicity of cephalosporins, and in particular cephaloridine, may also be increased in the presence of gentamicin. Consequently, if this combination is used monitoring of kidney function is advised.

Neuromuscular blockade and respiratory paralysis have been reported from administration of aminoglycosides to patients who have received curare-type muscle relaxants during anaesthesia.

4.6 Pregnancy and lactation

There are no proven cases of intrauterine damage caused by gentamicin. However, in common with most drugs known to cross the placenta, usage in pregnancy should only be considered in life threatening situations where expected benefits outweigh possible risks. In the absence of gastro-intestinal inflammation, the amount of gentamicin ingested from the milk is unlikely to result in significant blood levels in breast-fed infants.

4.7 Effects on ability to drive and use machines

Not known.

4.8 Undesirable effects

Side-effects include vestibular damage or hearing loss, particularly after exposure to ototoxic drugs or in the presence of renal dysfunction. Nephrotoxicity (usually reversible) and occasionally acute renal failure, hypersensitivity, anaemia, blood dycrasias, purpura, stomatitis, convulsions and effects on liver function occur occasionally.

Rarely hypomagnesia on prolonged therapy and antibiotic–associated colitis have been reported.

Nausea, vomiting and rash have also been reported.

Central neurotoxicity, including encephalopathy, confusion, lethargy, mental depression and hallucinations, has been reported in association with gentamicin therapy but this is extremely rare. Peripheral neuropathy has also been reported but the frequency of occurrence of this side effect is unknown.

Reporting of suspected adverse reactions

Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard.

4.9 Overdose

Haemodialysis and peritoneal dialysis will aid the removal from blood but the former is probably more efficient. Calcium salts given intravenously have been used to counter the neuromuscular blockade caused by gentamicin.

5. Pharmacological properties
5.1 Pharmacodynamic properties

Gentamicin is a mixture of antibiotic substances produced by the growth of micromonospora purpurea. It is bactericidal with greater antibacterial activity than streptomycin, neomycin or kanamycin.

Gentamicin exerts a number of effects on cells of susceptible bacteria. It affects the integrity of the plasma membrane and the metabolism of RNA, but its most important effects is inhibition of protein synthesis at the level of the 30s ribosomal subunit.

5.2 Pharmacokinetic properties

Gentamicin is not readily absorbed from the gastro-intestinal tract. Gentamicin is 70-85% bound to plasma albumin following administration and is excreted 90% unchanged in urine. The half-life for its elimination in normal patients is 2 to 3 hours.

Effective plasma concentration is 4-8 µg/ml.

The volume of distribution (vd) is 0.3 l/kg.

The elimination rate constant is:

0.02 hr-1 for anuric patients *

0.30 hr-1 normal

* Therefore in those with anuria care must be exercised following the usual initial dose, any subsequent administration being reduced in-line with plasma concentrations of gentamicin.

5.3 Preclinical safety data

Not applicable.

6. Pharmaceutical particulars
6.1 List of excipients

Sodium Chloride BP

Water for Injections BP

6.2 Incompatibilities

In general, gentamicin injection should not be mixed. In particular the following are incompatible in mixed solution with gentamicin injection: penicillins, cephalosporins, erythromycin, heparins, sodium bicarbonate. * Dilution in the body will obviate the danger of physical and chemical incompatibility and enable gentamicin to be given concurrently with the drugs listed above either as a bolus injection into the drip tubing, with adequate flushing, or at separate sites. In the case of carbenicillin, administration should only be at a separate site.

* Carbon dioxide may be liberated on addition of the two solutions. Normally this will dissolve in the solution but under some circumstances small bubbles may form.

6.3 Shelf life

36 months

6.4 Special precautions for storage

Store in a cold place.

6.5 Nature and contents of container

Cidomycin Intrathecal Injection is supplied in 1ml neutral glass ampoules in packs of 5.

6.6 Special precautions for disposal and other handling

Not applicable.

7. Marketing authorisation holder

Zentiva Pharma UK Limited

One Onslow Street

Guildford

Surrey

GU1 4YS

United Kingdom

Trading as:

Zentiva, One Onslow Street, Guildford, Surrey, GU1 4YS, UK

8. Marketing authorisation number(s)

PL 17780/0506

9. Date of first authorisation/renewal of the authorisation

01/12/2009

10. Date of revision of the text

31st July 2018