Consumer medicine information

Tobrex

Tobramycin

BRAND INFORMATION

Brand name

Tobrex

Active ingredient

Tobramycin

Schedule

S4

 

Consumer medicine information (CMI) leaflet

Please read this leaflet carefully before you start using Tobrex.

What is in this leaflet

Please read this leaflet carefully before you use Tobrex Eye Drops and Tobrex Eye Ointment.

This leaflet answers some common questions about Tobrex Eye Drops and Ointment. It does not contain all of the available information. It does not take the place of talking to your doctor or pharmacist.

The information in this leaflet was last updated on the date listed on the final page. More recent information on the medicine may be available.

You should ensure that you speak to your pharmacist or doctor to obtain the most up to date information on the medicine.

You can also download the most up to date leaflet from www.novartis.com.au The updates may contain important information about the medicine and its use of which you should be aware.

All medicines have risks and benefits. Your doctor has weighed the expected benefits of you using Tobrex against the risks this medicine could have for you.

The information in this leaflet applies to Tobrex only. This information does not apply to similar products, even if they contain the same ingredients.

If you have any concerns about using this medicine, ask your doctor or pharmacist.

Keep this leaflet with the medicine. You may need to read it again.

What Tobrex is used for

Tobrex is used to treat bacterial infections of the external part of the eye.

Tobrex contains tobramycin which is an "aminoglycoside" antibiotic.

Before prescribing Tobrex, your doctor will have examined your eye(s) and decided that Tobrex is the right medicine for you.

Ask your doctor if you have any questions about why this medicine has been prescribed for you. Your doctor may have prescribed Tobrex for another reason.

This medicine is only available with a doctor's prescription.

There is no evidence that Tobrex is addictive.

Use in children

Do not use Tobrex in children under 12 months of age. The safety and effectiveness of Tobrex in children under the age of 12 months has not been established.

Before you use Tobrex

When you must not use it

Do not use this medicine if you have an allergy to:

  • Tobramycin or other aminoglycoside antibiotics
  • Any of the ingredients listed at the end of this leaflet under "Product description".

Some of the symptoms of an allergic reaction may include:

  • Shortness of breath, wheezing or difficulty breathing
  • Swelling of the face, lips, tongue or other parts of the body
  • Rash, itching or hives on the skin.

Do not use Tobrex if the:

  • Safety seal on the eye drop bottle is broken
  • Seal on the ointment carton was broken before you opened it for the first time
  • Bottle, tube or packaging shows signs of tampering
  • Expiry date on the bottle, tube or carton has passed.

If you use this medicine after the expiry date has passed, it may not work.

Do not put Tobrex in your eye(s) while you are wearing contact lenses. Tobrex Eye Drops contain the preservative, benzalkonium chloride, which can deposit in soft contact lenses.

The ointment base used in Tobrex Eye Ointment may be very difficult to clean off your lenses.

You can put your contact lenses back into your eye 15 minutes after you have used Tobrex.

Ask your doctor for advice if you have ever had conditions such as myasthenia gravis or Parkinson's disease. Aminoglycoside antibiotics may worsen muscle weakness.

If you are not sure whether you should start using this medicine, talk to your doctor.

Before you start to use it

Tell your doctor if you have had an allergy to any other medicines or any other substances, such as foods, preservatives or dyes.

Tell your doctor if you are pregnant or plan to become pregnant. Your doctor will discuss the risks and benefits of using Tobrex when pregnant.

Tell your doctor if you are breastfeeding or plan to breastfeed. Your doctor will discuss the risks and benefits of using Tobrex when breastfeeding.

Taking or using other medicines

Tell your doctor or pharmacist if you are taking or using any other medicines. This includes other eye drops, ointments or any other medicines that you get without a prescription from a pharmacy, supermarket or health food shop.

Some medicines and Tobrex may interfere with each other. These include:

  • beta lactam type antibiotics that are used to treat infections of the eye, ear or the skin
  • medicines that can lead to hearing loss
  • other aminoglycoside antibiotics that are similar to tobramycin.

These medicines may be affected by Tobrex or may affect how well it works. You may need different amounts of your medicines or you may need to take different medicines.

Ask your doctor or pharmacist for help if you are not sure if you are using or taking any of the above medicines.

Your doctor or pharmacist has more information on medicines to be careful with or avoid while using this medicine.

How to use Tobrex

Carefully follow all directions given to you by your doctor and pharmacist. They may differ from the information contained in this leaflet.

If you do not understand the instructions on the carton / bottle, ask your doctor or pharmacist for help.

How much to use

The adult dose of Tobrex will depend on the type and severity of the infection.

Tobrex Eye Drops

The usual dose in severe infection is 2 drops in the affected eye(s) every hour until your condition improves.

The usual dose in mild to moderate infection is 1 to 2 drops in the affected eye(s) every four hours.

Tobrex Eye Ointment

The usual dose in severe infection is a 1 to 1 1/2 cm ribbon applied to the affected eye(s) every three to four hours.

The usual dose in mild to moderate infection is a 1 to 1 1/2 cm ribbon applied to the affected eye(s) two to three times a day.

Your doctor will tell you how much Tobrex you need to use each day.

How to use it

It is important to use Tobrex exactly as your doctor or pharmacist has told you. If you use it less often than you should, it may not work as well and the eye problem may not improve. Using it more often than you should may not improve the eye problem any faster and may cause increased side effects.

If you are wearing soft contact lenses, remove them before putting either the drops or ointment in your eye.

Follow these steps to use Tobrex Eye Drops:

  1. Wash your hands thoroughly with soap and water.
  2. Immediately before using a bottle for the first time, break the safety seal around the neck area and throw the loose plastic ring away.
  3. Remove the cap from the bottle.
  4. Hold the bottle upside down in one hand between your thumb and middle finger (see Diagram 1).

  1. While tilting your head back, gently pull down the lower eyelid of your eye to form a pouch / pocket.
  2. Place the tip of the bottle close to your eye. Do not let it touch your eye.
  3. Place the dropper tip close to, but not touching, your lower eyelid and gently tap or press the base of the bottle with your forefinger to release one drop (see Diagrams 2 and 3).

  1. Close your eye. Do not blink or rub your eye.
  2. While your eye is closed, place your index finger against the inside corner of your eye and press against your nose for about two minutes. This will help to stop the medicine from draining through the tear duct to the nose and throat, from where it can be absorbed into other parts of your body. This will also reduce the unpleasant taste sensation that some people experience when using these drops.
  3. If necessary, repeat the above steps for the other eye.
  4. Your eyelids can only hold less than one drop at a time, so it is normal for a small amount of the eye drop to spill onto your cheek. You should wipe away any spillage with a tissue.
  5. Replace the cap on the bottle, closing it tightly.
  6. Wash your hands again with soap and water to remove any residue.

If you have trouble knowing whether you have placed your drops correctly, you may want to store them in the fridge. Some people find it easier to feel the drops if they are cold.

Follow these steps to use Tobrex Eye Ointment:

  1. Wash your hands thoroughly with soap and water.
  2. Remove the cap from the tube. Using your forefinger, gently pull your lower eyelid down to form a pouch (see Diagram 1).

  1. Using your other hand, carefully squeeze a small ribbon (about 1 to 1 1/2 cm) of ointment into the pouch (see Diagram 2).

  1. Making sure that the ointment remains within the eye, slowly close your eye without blinking (see Diagrams 3 and 4). Keep your eye closed for 1 to 2 minutes.

  1. If necessary, repeat the above steps 1-4 for your other eye.
  2. Place the cap on the tube and close it tightly.
  3. Wash your hands again with soap and water to remove any residue. You may feel a slight burning sensation in the eye shortly after using the eye drops or ointment. If this persists, or is very uncomfortable, contact your doctor or pharmacist.

Be careful not to touch the tip of the eye drop bottle or eye ointment tube with your fingers, the eye or anything else. This will help prevent the eye drops or ointment becoming dirty or contaminated.

After using Tobrex wait at least 5 minutes before putting any other eye drops or ointment in your eye(s).

Wait 15 minutes before replacing your contact lenses.

If you are being changed from Tobrex to a new medicine, follow your doctor’s instructions carefully as to when to stop Tobrex and when to start the new medicine.

When to use it

Use Tobrex at about the same time every day unless your doctor tells you otherwise. Using Tobrex at the same time each day will have the best effect on your eye infection. It will also help you remember when to use your medicine.

How long to use it

Keep using Tobrex for the full time of treatment, even if you begin to feel better after a few days. If you do not complete the full course prescribed by your doctor, the infection may not clear completely and your symptoms may return.

If you are unsure about when or how to stop using Tobrex, talk to your doctor or pharmacist.

If you forget to use it

If it is almost time for your next dose, skip the dose you missed and use your next dose when you are meant to.

Otherwise, use Tobrex as soon as you remember, and then go back to using it as you would normally.

Do not use a double dose to make up for the dose that you missed. This may increase the chance of you getting an unwanted side effect.

If you are not sure what to do, ask your doctor or pharmacist.

If you have trouble remembering to use your medicine, ask your pharmacist for some hints.

If you use too much (overdose)

If you accidentally put too many eye drops or ointment in your eye(s) immediately rinse your eye(s) with lukewarm water.

If you think that you or someone else has swallowed any or all of the contents of Tobrex Eye Drops or Tobrex Eye Ointment, immediately telephone your doctor, the Poisons Information Centre on 13 11 26 for advice or go to Accident and Emergency at the nearest hospital. Do this even if there are no signs of discomfort or poisoning.

While you are using Tobrex

Things you must do

If the symptoms of your infection do not improve within a few days, or if they become worse, tell your doctor.

Tell your doctor if, for any reason, you have not used Tobrex exactly as prescribed. Otherwise your doctor may think that it was not effective and change the treatment unnecessarily.

If you are about to start taking any new medicine, tell your doctor and pharmacist that you are using Tobrex.

Tell all the doctors, dentists and pharmacists who are treating you that you are using Tobrex.

If you become pregnant while using Tobrex, tell your doctor immediately.

Things you must not do

Do not use Tobrex to treat any other complaints unless your doctor tells you to.

Do not give Tobrex to anyone else, even if they have the same condition as you.

Do not stop using Tobrex or lower the dosage because you are feeling better, without checking with your doctor. If you do not complete the full course prescribed by your doctor, all of the bacteria causing your infection may not be killed. These bacteria may continue to grow and multiply so that your infection may not clear completely or it may return.

Do not let children handle Tobrex Eye Drops or Tobrex Eye Ointment.

Things to be careful of

Be careful driving or operating machinery until you know how Tobrex affects you and your vision. As with any eye medicines, temporary blurred vision or other visual disturbances may affect the ability to drive or use machines. If blurred vision occurs when you put the drops or ointment in the eye, wait until your vision is clear before driving or using machinery.

Side effects

Tell your doctor or pharmacist as soon as possible if you do not feel well while you are using Tobrex.

This medicine helps most people with eye infections, but it may have unwanted side effects in a few people. All medicines can have side effects. Sometimes they are serious, most of the time they are not. You may need medical treatment if you get some of the side effects.

Do not be alarmed by the following list of possible side effects. You may not experience any of them.

Ask your doctor or pharmacist to answer any questions you may have.

Tell your doctor or pharmacist if you notice any of the following and they worry you:

  • eye irritation or feeling of having something in the eye
  • inflammation of the cornea (clear front portion of your eye) (punctate keratitis)
  • swollen / itchy eyelids
  • eye redness
  • increased tearing.

These are the more common side effects of your medicine. They are usually mild and short-lived.

If any of the following happen, stop using Tobrex and tell your doctor immediately or go to Accident and Emergency at your nearest hospital:

  • skin rash
  • swelling of the face, hands or feet
  • wheezing, difficulty in breathing, shortness of breath
  • severe and sudden onset of pinkish, itchy swellings on the skin, also called hives or nettle rash.

These hypersensitivity reactions can be very serious side effects. You may need urgent medical attention or may need to go to hospital. These side effects are very rare.

Additional side effects that could be noticed include:

  • loss of eyelashes
  • lightening of skin.

Tell your doctor or pharmacist if you notice anything that is making you feel unwell.

Other side effects not listed above may also occur in some people.

After using Tobrex

Storage

Keep your Tobrex Eye Drops and Eye Ointment in a cool dry place where the temperature stays below 25°C.

Do not freeze.

It is not necessary to store Tobrex in the refrigerator.

However, Tobrex Eye Drops may be kept in the refrigerator if you prefer to instil cold drops.

Do not leave the cap off the eye drop bottle or the eye ointment tube for any length of time to avoid contaminating your drops or ointment.

Do not carry Tobrex Eye Ointment in the pockets of your clothes.

Do not store Tobrex or any other medicine in the bathroom or near a sink. Do not leave it on a window sill or in the car. Heat and dampness can destroy some medicines.

Keep it where children cannot reach it. A locked cupboard at least one-and a half metres above the ground is a good place to store medicines.

Disposal

Write the date on the bottle or tube of Tobrex when your first open your medicine and throw out any remaining drops or ointment after four weeks. Tobrex Eye Drops and Tobrex Eye Ointment contain a preservative which helps prevent germs growing in the medicine in the first four week. After this time there is a greater risk of contamination which can cause eye infection. A new bottle or a new tube should be opened.

If your doctor tells you to stop using Tobrex or the expiry date has passed, ask your pharmacist what to do with any medicine that is left over.

Product description

What it looks like

Tobrex Eye Drops come in a 5 mL plastic bottle with screw cap.

Tamper evidence is provided with a safety seal around the neck area of the bottle.

Tobrex Eye Ointment comes in a 3.5 g aluminium tube and plastic cap.

Ingredients

The active ingredient in Tobrex Eye Drops is tobramycin 3.0 mg in 1 mL (0.3%).

Tobrex Eye Drops also contain:

  • benzalkonium chloride (0.1 mg/mL) as preservative
  • boric acid
  • sodium sulfate
  • sodium chloride
  • tyloxapol
  • sodium hydroxide and/or sulfuric acid (to adjust pH)
  • purified water.

The pH range of Tobrex Eye Drops is between 7.0 and 8.0.

The active ingredient in Tobrex Eye Ointment is tobramycin 3 mg in 1 g (0.3).

Tobramycin Eye Ointment also contains:

  • chlorobutanol 0.5% (5 mg) as preservative
  • mineral oil
  • petroleum base

Allergens:

May contain traces of soya beans.

Supplier

Tobrex Eye Drops and Eye Ointment are supplied in Australia by:

Novartis Pharmaceuticals Australia Pty Limited
ABN 18 004 244 160
54 Waterloo Road
Macquarie Park NSW 2113
Telephone: 1-800-671-203
Web site: www.novartis.com.au

Australian Registration Number

Tobrex Eye Drops: AUST R No. 25365

Tobrex Eye Ointment: AUST R No. 25364

Date of Preparation

This leaflet was prepared in November 2023.

® Registered trademark

Internal document code:
(tox201123c) based on PI (tox201123i)

Published by MIMS January 2024

BRAND INFORMATION

Brand name

Tobrex

Active ingredient

Tobramycin

Schedule

S4

 

1 Name of Medicine

Tobramycin.

2 Qualitative and Quantitative Composition

Each mL of Tobrex Eye Drops contains tobramycin 0.3% (3 mg).
Each gram of Tobrex Eye Ointment contains tobramycin 0.3% (3 mg).
May contain traces of potential allergens such as soya beans from the manufacturing process.
For the full list of excipients, see Section 6.1 List of Excipients.

3 Pharmaceutical Form

Tobrex (tobramycin) 0.3% Eye Drops and Tobrex (tobramycin) 0.3% Eye Ointment (Tobrex) are sterile topical antibiotic formulations prepared specifically for topical therapy of bacterial eye infections. Tobrex Eye Drops has a pH range between 7.0 and 8.0.

4 Clinical Particulars

4.1 Therapeutic Indications

Tobrex (tobramycin) Eye Drops and Tobrex (tobramycin) Eye Ointment are topical antibiotics indicated in the treatment of external infections of the eye and its adnexa caused by susceptible bacteria. Appropriate monitoring of bacterial response to topical antibiotic therapy should accompany the use of Tobrex.

4.2 Dose and Method of Administration

Dosage.

Tobrex eye drops.

In mild to moderate disease, instill one or two drops into the affected eye(s) every four hours. In severe infections, instill two drops into the eye(s) hourly until improvement.

Tobrex eye ointment.

In mild to moderate disease, apply a 1-1.5 cm ribbon into the affected eye(s) two or three times per day. In severe infections, apply a 1-1.5 cm ribbon every three to four hours until improvement.
Treatment with Tobrex should be reduced prior to discontinuation. The usual duration of treatment is 7-10 days.

4.3 Contraindications

Tobrex (tobramycin) Eye Drops and Eye Ointment are contraindicated in patients with known hypersensitivity to tobramycin or to other aminoglycosides or any other ingredients in this product.

4.4 Special Warnings and Precautions for Use

For topical ophthalmic use only. Not for injection into the eye.

Hypersensitivity.

Sensitivity to topically administered aminoglycosides may occur in some patients. Severity of hypersensitivity reactions may vary from local effects to generalized reactions such as erythema, itching, urticarial, skin rash, anaphylaxis, anaphylactoid reactions, or bullous reactions. If hypersensitivity develops with this product, discontinue use and institute appropriate therapy.
If Tobrex (topical tobramycin) Eye Drops or Eye Ointment are administered concomitantly with systemic aminoglycoside antibiotics, care should be taken to monitor the total serum concentration. Serious adverse reactions including neurotoxicity, ototoxicity and nephrotoxicity have occurred in patients receiving systemic aminoglycoside therapy. Although these effects have not been reported following topical ocular use of tobramycin, caution is advised when using Tobrex Eye Drops or Tobrex Eye Ointment concomitantly with systemic aminoglycosides.

General.

As with any antibiotic, prolonged use may result in overgrowth of non-susceptible organisms, including fungi. If superinfection occurs, appropriate therapy should be initiated.
Cross sensitivity to other aminoglycoside antibiotics may occur. The possibility that patients that become sensitised to topical ocular tobramycin may also be sensitive to other topical and/or systemic aminoglycosides should be considered.
Ophthalmic solutions and ointments may retard corneal wound healing.

Renal, auditory, vestibular, or neuromuscular impairment.

Patients receiving concomitant parenteral tobramycin (aminoglycoside) and topical tobramycin therapies should be monitored as clinically appropriate. Caution should be exercised with known or suspected renal, auditory, vestibular, or neuromuscular dysfunction.
Caution should be exercised when prescribing Tobrex (tobramycin) Eye Drops or Eye Ointment to patients with known or suspected neuromuscular disorders such as myasthenia gravis or Parkinson's disease. Aminoglycosides may aggravate muscle weakness because of their potential effect on neuromuscular function.

Contact lenses.

Neither Tobrex (tobramycin) Eye Drops nor Eye Ointment should be instilled while the patient is wearing contact lenses. Contact lens wear is not recommended during treatment of an ocular infection.
If patients continue to wear contact lenses while under treatment with Tobrex Eye Drops, they should remove their lens(es) prior to instilling the drops in the affected eye(s). Lens(es) should not be inserted into the eye(s) until 15 minutes after instillation of the drops. Tobrex Eye Drops contains benzalkonium chloride which may cause eye irritation and is known to discolour soft contact lenses. Avoid contact with soft contact lenses.
Due to the nature of the ointment base, patients should be advised not to wear their contact lenses while they are being treated with Tobrex Eye Ointment.

Use in hepatic and renal impairment.

Tobrex (tobramycin) Eye Drops or Eye Ointment have not been studied in these patient populations. However, due to low systemic absorption of tobramycin after topical administration of this product, dose adjustment is not necessary.

Use in the elderly.

No overall differences in safety or effectiveness have been observed between elderly and other adult patients.

Paediatric use.

Safety and effectiveness in children below the age of 1 year have not been established.

Effects on laboratory tests.

No data available.

4.5 Interactions with Other Medicines and Other Forms of Interactions

If Tobrex (topical tobramycin) Eye Drops or Eye Ointment are used while the patient is on a systemic aminoglycoside antibiotic, the patient's total serum aminoglycoside concentration should be monitored.
Concurrent and/or sequential use of Tobrex with other drugs with neurotoxic or ototoxic potential should be avoided.
Do not use Tobrex simultaneously with a topical beta lactam type antibiotic as this is likely to result in inactivation of tobramycin.

4.6 Fertility, Pregnancy and Lactation

Effects on fertility.

Studies have not been performed to evaluate the effect of topical ocular administration of Tobrex (tobramycin) Eye Drops or Eye Ointment on human fertility.
(Category B3)
There are no adequate, well controlled studies using the topical administration of Tobrex (tobramycin) Eye Drops or Eye Ointment in pregnant women.
A published retrospective assessment of women receiving parenteral aminoglycosides during pregnancy suggested no detectable teratogenic risk to the foetus. The number of women treated with parenteral tobramycin in this study was very small, 2 in the case group and 4 in the control group and so no firm specific conclusions with regard to tobramycin exposure can be drawn from this study. However, the study concluded that parenteral administration of gentamicin and oral neomycin during pregnancy presents no detectable teratogenic risk to the foetus, when restricted to structural developmental abnormalities. This conclusion can be extended to the class of aminoglycoside antibiotics as a whole.
Studies in animals have shown evidence of an increased occurrence of foetal damage following systemic administration of aminoglycosides to pregnant mothers. There is evidence of selective uptake of aminoglycosides by the foetal kidney resulting in damage (probably reversible) to immature nephrons. Eighth cranial nerve damage has also been reported following in utero exposure to some of the aminoglycosides. Because of their chemical similarity, all aminoglycosides must be considered potentially nephrotoxic and ototoxic to the foetus. It should also be noted that therapeutic blood concentrations in the mother do not equate with safety for the foetus.
There is no firm data concerning the detectable blood concentrations in mothers or tissue concentrations in the foetus. The systemic absorption of tobramycin after topical administration of Tobrex is expected to be low.
Tobrex should be used during pregnancy only if the potential benefit for the mother justifies the potential risk to the foetus otherwise tobramycin is not recommended during pregnancy.
There are no adequate, well controlled studies using the topical administration of Tobrex (tobramycin) Eye Drops or Eye Ointment in women who are breastfeeding. It is unknown whether tobramycin is excreted in human milk following topical ocular administration. Tobramycin is excreted in human milk after systemic administration. Risk to the breastfed child cannot be excluded. Tobrex should be used only if the potential benefit for the mother justifies the potential risk to the infant.

4.7 Effects on Ability to Drive and Use Machines

As with other ophthalmic medications, temporary blurred vision or other visual disturbances may affect the ability to drive or use machines. If blurred vision occurs upon application, the patient must wait until the vision clears before driving or using machinery.

4.8 Adverse Effects (Undesirable Effects)

Reporting suspected adverse effects.

Reporting suspected adverse reactions after registration 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 at www.tga.gov.au/reporting-problems.
The most frequent adverse reactions to Tobrex (tobramycin) Eye Drops and Eye Ointment are localised ocular toxicity and hypersensitivity, including punctate keratitis, eye and lid itching, lid swelling, ocular hyperaemia, conjunctival erythema and lacrimation. These reactions occur in approximately 3% of patients treated with Tobrex.
Other adverse reactions associated with ophthalmic tobramycin are burning and stinging of the eyes. For ophthalmic ointment dosage form: blurred vision.
A summary of treatment emergent adverse events based on literature and post-marketing experience and their estimate of frequencies (very common, common, uncommon, rare, very rare, and not known) in accordance with preferred term and system organ classes (SOC) of any severity are listed below.
Within each frequency-grouping, undesirable effects are presented in decreasing order of seriousness. These adverse reactions were observed following ophthalmic use of tobramycin eye drops and/or eye ointment:

Immune system disorders.

Uncommon (> 0.1% to ≤ 1%): hypersensitivity.
Not known: anaphylactic reaction.

Nervous system disorders.

Uncommon (> 0.1% to ≤ 1%): headache.

Eye disorders.

Common (> 1% to < 10%): ocular discomfort, ocular hyperaemia.
Uncommon (> 0.1% to ≤ 1%): keratitis, corneal abrasion, conjunctival disorder, visual impairment, vision blurred, erythema of eyelid, conjunctival oedema, eyelid oedema, eyelid disorder, eye pain, dry eye, eye discharge, eye pruritus, foreign body sensation in eyes, lacrimation increased.
Not known: eye allergy, eye irritation, eyelids pruritus.

Skin and subcutaneous tissue disorders.

Uncommon (> 0.1% to ≤ 1%): urticaria, dermatitis, madarosis, leukoderma, pruritus, dry skin.
Not known: Stevens-Johnson syndrome, erythema multiforme, rash.
If topical ocular tobramycin is administered concomitantly with systemic aminoglycoside antibiotics, the possibility of increased systemic toxicity cannot be excluded and care should be taken to monitor the total serum concentration. Prolonged levels above 12 microgram/mL should be avoided.

4.9 Overdose

Clinically apparent signs and symptoms of Tobrex (tobramycin) Eye Drops or Eye Ointment overdose are not expected when used as above nor in the event of accidental ingestion of the contents of one bottle or tube. However, excessive local reactions may occur. In such cases treatment should be discontinued and appropriate treatment instituted.
A topical overdose of Tobrex may be flushed from the eye(s) with lukewarm water.
For information on the management of overdose, contact the Poisons Information Centre on 13 11 26 (Australia).

5 Pharmacological Properties

5.1 Pharmacodynamic Properties

Mechanism of action.

Tobramycin is actively transported across the bacterial cell membrane, and binds to a specific receptor protein on the 30S subunit of bacterial ribosomes and interferes with an initiation complex between messenger RNA (mRNA) and the 30S subunit, thus inhibiting protein synthesis.

Microbiology.

In vitro data.

In vitro studies have demonstrated tobramycin is active against susceptible strains of the following microorganisms:
Staphylococci, including S. aureus and S. epidermidis (coagulase-positive and coagulase-negative), including penicillin-resistant strains.
Streptococci, including some of the group A - beta-haemolytic species, some non-haemolytic species, and some Streptococcus pneumoniae.
Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Enterobacter aerogenes, Proteus mirabilis (indole-negative) and indole-positive Proteus species.
Bacterial resistance may develop upon prolonged use.
Tobramycin is not effective against most strains of group D Streptococci.

5.2 Pharmacokinetic Properties

No data available.

5.3 Preclinical Safety Data

Genotoxicity.

In vitro and in vivo studies with tobramycin did not reveal a mutagenic potential.

Carcinogenicity.

No studies have been conducted to evaluate the carcinogenic potential of tobramycin.

6 Pharmaceutical Particulars

6.1 List of Excipients

Tobrex (tobramycin) Eye Drops contain boric acid, sodium sulfate, sodium chloride, tyloxapol, sodium hydroxide and/or sulphuric acid (to adjust pH) and purified water. Each mL of Tobrex Eye Drops contains benzalkonium chloride 0.01% (0.1 mg) as preservative.
Tobrex (tobramycin) Eye Ointment contains mineral oil and petroleum base. Each gram of Tobrex Eye Ointment contains chlorobutanol 0.5% (5 mg) as preservative.

6.2 Incompatibilities

Incompatibilities were either not assessed or not identified as part of the registration of this medicine.

6.3 Shelf Life

In Australia, information on the shelf life can be found on the public summary of the Australian Register of Therapeutic Goods (ARTG). The expiry date can be found on the packaging.

6.4 Special Precautions for Storage

Store below 25°C. Discard container 4 weeks after opening.

6.5 Nature and Contents of Container

Tobrex (tobramycin) eye drops.

5 mL LDPE bottle with PP closure.

Tobrex (tobramycin) eye ointment.

3.5 g aluminium tubes with HDPE and/or LDPE nozzle.

6.6 Special Precautions for Disposal

In Australia, any unused medicine or waste material should be disposed of by taking to your local pharmacy.

6.7 Physicochemical Properties

Chemical structure.

The chemical structure of tobramycin is represented as:
Chemical name: 4-O-(3-amino-3-deoxy-α-D-glucopyranosyl)- 2-deoxy-6-O-(2,6-diamino-2,3,6-trideoxy- α-D-ribo-hexopyranosyl)-L-streptamine.
Empirical formula: C18H37N5O9.
Molecular weight: 467.5.

CAS number.

32986-56-4.

7 Medicine Schedule (Poisons Standard)

Schedule 4 - Prescription Only Medicine.

Summary Table of Changes