Tobramycin

Description

Tobramycin ophthalmic solution, USP 0.3% is a sterile topical ophthalmic antibiotic formulation designed for the treatment of external ophthalmic infections. Each milliliter of this solution contains 0.3% tobramycin (3 mg) as the active ingredient, along with 0.01% benzalkonium chloride (0.1 mg) as a preservative. The formulation includes inactive ingredients such as boric acid, sodium sulfate, sodium chloride, tyloxapol, sodium hydroxide and/or sulfuric acid (for pH adjustment), and purified water.

The pH of tobramycin ophthalmic solution, USP 0.3% ranges from 7.0 to 8.0, with an osmolality of 260-320 mOsm/kg. Tobramycin, a water-soluble aminoglycoside antibiotic, exhibits activity against a broad spectrum of gram-negative and gram-positive ophthalmic pathogens. The molecular weight of tobramycin is 467.52, and its molecular formula is C₁₈H₃₇N₅O₉. The chemical name of tobramycin is 0-{3-amino-3-deoxy-α-D-gluco-pyranosyl-(1→4)} -0-{2,6-diamino-2,3,6-trideoxy-α-D-ribohexopyranosyl-(1→6)}-2-deoxystreptamine.

Uses and Indications

Tobramycin ophthalmic solution, 0.3%, is indicated for the treatment of external infections of the eye and its adnexa caused by susceptible bacteria. This topical antibiotic is effective in managing bacterial infections and is supported by clinical studies demonstrating its safety and efficacy in pediatric populations.

Appropriate monitoring of bacterial response to topical antibiotic therapy should accompany the use of tobramycin ophthalmic solution, 0.3%, to ensure optimal therapeutic outcomes.

Dosage and Administration

In cases of mild to moderate disease, the recommended dosage is to instill 1 or 2 drops into the affected eye(s) every 4 hours. For severe infections, the dosage is increased to instilling 2 drops into the eye(s) hourly until clinical improvement is observed. Following improvement, the frequency of administration should be gradually reduced before discontinuation of treatment.

Contraindications

Tobramycin ophthalmic solution, 0.3%, is contraindicated in patients with known hypersensitivity to any of its components.

Additionally, patients should be advised against wearing contact lenses if they exhibit signs and symptoms of bacterial ocular infection, as this may exacerbate the condition.

Warnings and Precautions

Topical ophthalmic use is the only approved route for administration of this product; it is strictly contraindicated for injection into the eye. Healthcare professionals should be aware that some patients may exhibit sensitivity to topically applied aminoglycosides. The severity of hypersensitivity reactions can range from localized effects to more generalized responses, including erythema, itching, urticaria, skin rash, anaphylaxis, anaphylactoid reactions, or bullous reactions. In the event of a sensitivity reaction to tobramycin ophthalmic solution, 0.3%, it is imperative to discontinue use immediately.

Prolonged use of this antibiotic preparation may lead to the overgrowth of nonsusceptible organisms, including fungi. Should a superinfection occur, it is essential to initiate appropriate therapy without delay. Additionally, cross-sensitivity to other aminoglycoside antibiotics may be observed; therefore, if hypersensitivity develops with this product, it is crucial to discontinue use and implement suitable therapeutic measures.

Patients should be counseled against wearing contact lenses if they present with signs and symptoms indicative of a bacterial ocular infection. This precaution is vital to prevent exacerbation of the condition and to ensure optimal therapeutic outcomes.

Side Effects

Patients receiving tobramycin ophthalmic solution, 0.3%, may experience a range of adverse reactions. Common adverse reactions include hypersensitivity and localized ocular toxicity, which encompasses lid itching, swelling, and conjunctival erythema. These reactions are reported to occur in less than three of 100 patients treated with the solution.

In addition to common reactions, there are notable postmarketing experiences that include serious adverse events such as anaphylactic reactions, Stevens-Johnson syndrome, and erythema multiforme.

Additional adverse reactions that may occur, although less frequently, include neurotoxicity, ototoxicity, and nephrotoxicity, particularly associated with systemic aminoglycosides. Furthermore, patients with known or suspected neuromuscular disorders, such as myasthenia gravis or Parkinson’s disease, may experience an aggravation of muscle weakness due to potential effects on neuromuscular function.

It is important to note that sensitivity to topically applied aminoglycosides, including tobramycin, may occur in some patients. The severity of hypersensitivity reactions can vary, ranging from local effects to more generalized reactions, which may include erythema, itching, urticaria, skin rash, and in severe cases, anaphylaxis or anaphylactoid reactions, including bullous reactions. If a sensitivity reaction occurs, discontinuation of the medication is advised.

Drug Interactions

Cross-sensitivity to other aminoglycoside antibiotics may occur. In the event that hypersensitivity develops with this product, it is advised to discontinue use and initiate appropriate therapy.

Aminoglycosides have the potential to exacerbate muscle weakness in patients with known or suspected neuromuscular disorders, including myasthenia gravis or Parkinson’s disease. This effect is attributed to their impact on neuromuscular function. Monitoring for signs of increased muscle weakness in these patients is recommended.

Packaging & NDC

The table below lists all NDC Code configurations of Tobramycin, the U.S. brand-name prescription product. Columns show Packaging, Formulation Type, and Active Ingredient Strength.

Pediatric Use

Safety and effectiveness in pediatric patients below the age of 2 months have not been established. Therefore, caution is advised when considering treatment in this age group.

Geriatric Use

Elderly patients, defined as those aged 65 years and older, have not demonstrated any overall clinical differences in safety or effectiveness when compared to younger patients. Therefore, no specific dosage adjustments are necessary for this population based on age alone.

However, healthcare providers should remain vigilant in monitoring geriatric patients for any potential age-related changes that may affect drug metabolism and response. It is essential to consider individual patient factors, including comorbidities and concurrent medications, when prescribing to elderly patients to ensure optimal therapeutic outcomes.

Pregnancy

Reproduction studies in three types of animals at doses up to 33 times the normal human systemic dose have revealed no evidence of impaired fertility or harm to the fetus due to tobramycin. However, there are no adequate and well-controlled studies in pregnant women. Because animal studies are not always predictive of human response, tobramycin should be used during pregnancy only if clearly needed. Healthcare professionals should weigh the potential benefits against the risks when considering the use of this drug in pregnant patients.

Lactation

Because of the potential for adverse reactions in nursing infants from tobramycin ophthalmic solution, 0.3%, a decision should be made whether to discontinue nursing the infant or discontinue the drug, taking into account the importance of the drug to the mother.

Renal Impairment

Patients with renal impairment have not been specifically addressed in the available prescribing information. There are no dosage adjustments, special monitoring requirements, or safety considerations outlined for individuals with reduced kidney function. Healthcare professionals should exercise caution and consider the lack of data when prescribing to this patient population.

Hepatic Impairment

Patients with hepatic impairment have not been specifically studied in relation to the use of this medication. Consequently, there are no established dosage adjustments, special monitoring requirements, or precautions outlined for individuals with compromised liver function. It is recommended that healthcare providers exercise caution when prescribing this medication to patients with hepatic impairment, given the lack of data on its safety and efficacy in this population. Regular monitoring of liver function may be prudent in these cases, although specific parameters are not defined in the available information.

Overdosage

There is limited experience regarding the overdosage of tobramycin ophthalmic solution. In the event of an overdose, it is essential that treatment is focused on symptomatic and supportive care. Healthcare professionals should monitor the patient closely and provide appropriate interventions based on the symptoms presented.

Nonclinical Toxicology

Reproduction studies conducted in three animal species at doses up to 33 times the normal human systemic dose have demonstrated no evidence of impaired fertility or teratogenic effects associated with tobramycin. However, it is important to note that there are no adequate and well-controlled studies in pregnant women. Given that animal studies may not always accurately predict human responses, the use of this drug during pregnancy should be considered only when clearly necessary.

Postmarketing Experience

Postmarketing experience has identified additional adverse reactions associated with the use of the product. Reports include anaphylactic reactions, Stevens-Johnson syndrome, and erythema multiforme.

Furthermore, systemic aminoglycosides have been associated with neurotoxicity, ototoxicity, and nephrotoxicity in patients undergoing treatment. It has also been noted that aminoglycosides may exacerbate muscle weakness in individuals with known or suspected neuromuscular disorders, such as myasthenia gravis or Parkinson’s disease, due to their potential impact on neuromuscular function.

Patient Counseling

Patients should be advised not to wear contact lenses if they exhibit any signs or symptoms of a bacterial ocular infection. It is important to instruct patients to avoid touching the dropper tip to any surface, as this may lead to contamination of the solution.

In the event that a sensitivity reaction to tobramycin ophthalmic solution, 0.3% occurs, patients should be informed to discontinue use immediately. Additionally, if a superinfection develops, appropriate therapy should be initiated without delay.

Healthcare providers should discuss with patients the need to make a decision regarding nursing an infant while using this medication. This decision should consider the importance of the drug to the mother and whether to discontinue nursing or the medication itself.

Storage and Handling

Tobramycin ophthalmic solution, USP 0.3% is supplied in a suitable container that ensures the integrity of the product. It should be stored at a temperature range of 2° to 25°C (36° to 77°F) to maintain its efficacy.

Once opened, the solution can be used until the expiration date indicated on the bottle. It is important to handle the product with care to prevent contamination and ensure optimal performance.

Additional Clinical Information

Patients should be counseled to avoid touching the dropper tip to any surface to prevent contamination of the solution. Additionally, it is advised that patients refrain from wearing contact lenses if they exhibit signs and symptoms of a bacterial ocular infection.

Post-marketing experience has revealed additional adverse reactions, including anaphylactic reactions, Stevens-Johnson syndrome, and erythema multiforme. Furthermore, systemic aminoglycosides have been associated with neurotoxicity, ototoxicity, and nephrotoxicity. Clinicians should be aware that aminoglycosides may exacerbate muscle weakness in patients with known or suspected neuromuscular disorders, such as myasthenia gravis or Parkinson’s disease, due to their potential impact on neuromuscular function.

FDA Insert (PDF)

This document is the official FDA-approved prescribing information for Tobramycin as submitted by Sandoz Inc. It includes detailed information about indications, dosage, contraindications, warnings, and clinical pharmacology.

View full prescribing information (PDF)