Current health data shows 13.6% of global deaths are caused by bacterial infections.1 Bacterial infections can also occur in the eye, some of which can cause blindness if not addressed promptly. One medication used in the treatment of ocular and systemic infections is tobramycin.
This article looks at the following:
- Tobramycin applications and benefits
- Tobramycin side effects
- Safety precautions while using tobramycin
What is Tobramycin Ophthalmic Solution?
Tobramycin ophthalmic solution (TOBREX®) is an FDA-approved medication classified under aminoglycoside antibiotics.2 Aminoglycoside antibiotics are a class of medication that treat infections by inhibiting the growth of different types of bacteria.
Similar antibiotics include:
Tobramycin ophthalmic has a potency (strength) of 0.3%. You can use it alone or with other medications. Avoid taking tobramycin if you are allergic and have a viral or fungal infection, as it will cause more harm than good.
What is Tobramycin Used For?
Tobramycin solution is used to treat only bacterial infections. The drug is effective against gram-negative and gram-positive bacteria such as:3
- Staphylococcus aureus (S. aureus)
- Streptococcus pneumoniae (S. pneumoniae)
- Pseudomonas aeruginosa (P. aeruginosa)
- Neisseria gonorrhoeae
- Morraxella spp.
- Haemophilus influenza
To effectively suppress the bacteria, use tobramycin as directed by your doctor. Overuse or abuse of tobramycin can cause microbial resistance (decreased effectiveness).4
How to Use Tobramycin Properly
Use tobramycin as directed by your doctor. Your healthcare provider may prescribe one to two drops of tobramycin solution for mild to moderate infections. This prescription is usually administered every 4 to 6 hours for about 24 to 48 hours.
Your healthcare provider may prescribe two eye drops of tobramycin for severe infections, administered at frequent intervals (30 to 60 min). Reduce the frequency after improvement.
For Pseudomonas aeruginosa, a common drug-resistant strain, administering two drops at frequent intervals (every 5 min for 1 hour) is recommended.5
How to properly use tobramycin eye drops:
- Wash your hands before applying the medication
- Remove your contact lenses to prevent them from absorbing the eye drop ingredients
- Slightly tilt your head backward while facing up, and gently pull the lower eyelid to make a pouch
- With the other hand, hold the dropper above the eye and let the medicine drop inside the pouch
- Close your eyes and face downwards
- Apply gentle pressure at the corner of your eyes near the nose to prevent the medication from draining
- Close your eyes for about two minutes without rubbing or blinking
- If needed, wear your contact lenses 10-15 minutes after application
Repeat the steps for each eye every four hours. If you’re applying the tobramycin ophthalmic ointment, use your index finger to avoid transferring bacteria to the tip of the tube.
When you’re done using the medication, discard it properly. Consult your pharmacist or local waste disposal company on how to dispose of the medication safely.
How Quickly Does Tobramycin Start Working?
Tobramycin reaches its peak efficacy within 1 to 2 hours. The drug is carried around the body by the liver cells (hepatocytes) and excreted by the kidney (glomerular filtration).
You can feel the effectiveness of the medication within 2 to 3 days. Your infection should improve or go away within 5 to 7 days.
What are the Side Effects of Tobramycin?
Like every other medication, tobramycin, too, has side effects. Here is what to look out for:
- Burning eyes or stinging
- crusting or drainage of the eye
- Swollen eyelids
- Red eyes
- Temporary blurred vision (eye ointment)
- Excessively watery eyes
- Localized ocular toxicity (itching and swelling of conjunctiva)
Consult your doctor if you experience serious symptoms.
Does Tobramycin Affect the Liver?
Tobramycin eye drops don’t affect the liver due to minimal systemic absorption. That means the medication isn’t potent enough to circulate throughout the body.
Limited research shows acute liver injury with jaundice is associated with aminoglycoside therapy tobramycin. However, this doesn’t pertain to eye drops.
According to the National Library of Medicine, tobramycin therapy may induce hepatoxicity (injury to the liver).6 Symptoms may include skin rash, fever, or eosinophilia.
How Long Is it Safe to Use Tobramycin Eye Drops?
Your eye doctor will prescribe tobramycin eye drops, depending on the severity of your infection. Use the eye drops for 7 days or as prescribed even if your symptoms disappear after a few days. Failure to complete the full course may result in poor outcomes, including recurrence and resistance.
If you use the eye drops properly, the infection should clear within a week. Avoid prolonged or repeated periods of use, as this may reduce its efficacy or cause fungal infections.
There are situations when the risks of using tobramycin outweigh the benefits.7 Here are some safety considerations:
- If allergic to tobramycin, consult your health care professional for alternatives.
- Tobramycin is discouraged for infants under the age of 2 months.
- Tobramycin doesn’t interact well with some medications like aspirin, mannitol, furosemide, vecuronium, and metocurine. Inform your doctor of any other prescription drugs you’re taking before starting on tobramycin.
- Tobramycin solution is not recommended for pregnant and breastfeeding mothers. Consult your doctor if you’re pregnant, breastfeeding, or planning to be pregnant.
- Blurred vision is one side effect of tobramycin. Avoid driving or operating machinery if you’re unable to see clearly.
- Avoid wearing contact lenses until your active infection subsides.
What if You Miss a Dose?
If you miss a dose of tobramycin, take it as soon as you remember. However, if it’s almost time for the next dose, disregard the missed dosage and continue with your regular dosing schedule. Do not try to double the dose to compensate for the missed dose, as you risk an overdose.
Commonly Asked Questions
Below are answers to some of the commonly asked questions about tobramycin:
What are Tobramycin eye drops used for?
Tobramycin ophthalmic solution treats eye infections by killing the causative bacteria and stopping their growth. Stopping the medication or underdosing can result in reinfection and regrowth of the bacteria.
Is tobramycin a strong antibiotic?
Compared to other aminoglycoside antibiotics, tobramycin is considered strong and more effective with minimal side effects.
What is the minimum age for tobramycin use?
The minimum age for tobramycin administration is two years. Scientists have not yet determined the safety or efficacy for children below this age.
Is tobramycin and gentamicin the same?
Tobramycin and gentamicin fall under the same classification of aminoglycoside antibiotics. Studies indicate tobramycin is more effective and less toxic than gentamicin.8 Both drugs treat similar eye infections, and dosages vary depending on the degree of bacterial infection.
- Tobramycin is an effective antibiotic used for treating bacterial eye infections.
- The standard dosage is one drop every four hours and one drop every hour in severe infection.
- Unless the doctor says otherwise, you must use the medication for 5-7 days.
- Common tobramycin side effects include eye swelling, redness, itchiness, and a feeling or burning or stinging sensation.
- Avoid taking tobramycin with other drugs, as this may cause adverse reactions.
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