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 the 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 decahydrate, sodium chloride, tyloxapol, sodium hydroxide and/or sulfuric acid (for pH adjustment), and water for injection.

The pH of the solution 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 is O-3-Amino-3-deoxy-α-D-glucopyranosyl-(1→4)-O-2,6-diamino-2,3,6-trideoxy-α-D-ribo-hexopyranosyl-(1→6)-2-deoxy-L-streptamine.

Uses and Indications

Tobramycin ophthalmic solution USP, 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 USP, 0.3%. There are no reported teratogenic or nonteratogenic effects associated with this medication.

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 2 drops instilled 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 USP, 0.3% is contraindicated in patients with known hypersensitivity to any of its components. Use in these patients may lead to severe allergic reactions.

Warnings and Precautions

Topical ophthalmic use is the only approved route for administration of this medication; it is strictly contraindicated for injection into the eye. Healthcare professionals should be aware that some patients may exhibit sensitivity to topically applied aminoglycosides, which can lead to a range of hypersensitivity reactions.

The severity of these reactions can vary significantly, manifesting as localized effects or more generalized symptoms. Patients may experience erythema, itching, urticaria, skin rash, or in severe cases, anaphylaxis, anaphylactoid reactions, or bullous reactions. In the event that a patient develops a sensitivity reaction to tobramycin ophthalmic solution USP, 0.3%, it is imperative to discontinue use immediately to prevent further complications.

Healthcare providers are advised to monitor patients for any signs of hypersensitivity throughout the course of treatment.

Side Effects

Patients receiving tobramycin ophthalmic solution may experience a range of adverse reactions. The most frequently reported adverse reactions include hypersensitivity and localized ocular toxicity, which encompasses lid itching, swelling, and conjunctival erythema. These reactions are observed in less than three out of 100 patients treated with the solution.

Serious adverse reactions have also been reported in the postmarketing experience, including anaphylactic reactions, Stevens-Johnson syndrome, and erythema multiforme. Additionally, other adverse reactions that may occur include neurotoxicity, ototoxicity, and nephrotoxicity, particularly noted with systemic aminoglycosides. Patients with known or suspected neuromuscular disorders, such as myasthenia gravis or Parkinson’s disease, may experience an aggravation of muscle weakness.

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 localized effects to more generalized reactions, which may include erythema, itching, urticaria, skin rash, and in severe cases, anaphylaxis or anaphylactoid reactions. Should a sensitivity reaction occur, the use of tobramycin ophthalmic solution should be discontinued immediately.

Prolonged use of this medication may lead to the overgrowth of nonsusceptible organisms, including fungi. In the event of a superinfection, appropriate therapy should be initiated. Cross-sensitivity to other aminoglycoside antibiotics may also occur; therefore, if hypersensitivity develops with tobramycin ophthalmic solution, it is advised to discontinue use and implement suitable therapeutic measures.

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.

No specific drug or laboratory test interactions have been identified in the available data.

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. Clinical studies have demonstrated that tobramycin is safe and effective for use in children.

Geriatric Use

Elderly patients may not exhibit overall differences in safety or effectiveness compared to younger patients when treated with this medication. However, it is essential for healthcare providers to remain vigilant in monitoring this population, as individual responses may vary.

While specific dosage adjustments are not indicated based on age alone, clinicians should consider the overall health status, comorbidities, and concurrent medications of geriatric patients when determining the appropriate treatment regimen. Regular assessment and careful management are recommended to ensure optimal therapeutic outcomes in this demographic.

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 are advised to weigh the potential benefits against the risks when considering the use of this medication in pregnant patients.

Lactation

Because of the potential for adverse reactions in nursing infants from tobramycin ophthalmic solution, 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

There is no information available regarding the use of this medication in patients with hepatic impairment. Consequently, there are no dosage adjustments, special monitoring requirements, or precautions specified for individuals with compromised liver function. Healthcare professionals should exercise caution and consider the lack of data when prescribing this medication to patients with liver problems.

Overdosage

In the absence of specific information regarding overdosage, healthcare professionals are advised to exercise caution and adhere to general principles of management in cases of suspected overdose.

It is essential to monitor the patient closely for any potential symptoms that may arise, as the clinical presentation can vary depending on the substance involved. Common symptoms of overdose may include, but are not limited to, altered mental status, cardiovascular instability, respiratory distress, and gastrointestinal disturbances.

In the event of an overdose, immediate medical attention should be sought. Healthcare providers should initiate supportive care, which may include maintaining airway patency, providing supplemental oxygen, and monitoring vital signs. The use of activated charcoal may be considered if the patient presents within a suitable timeframe and if the ingestion was recent.

Additionally, specific antidotes or treatments may be indicated based on the substance involved in the overdose. Consultation with a poison control center or a medical toxicologist is recommended to guide the management of the patient and to determine the most appropriate interventions.

Overall, while specific overdosage information is not available, vigilance and prompt action are critical in managing potential overdose situations effectively.

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 of anaphylactic reactions, Stevens-Johnson syndrome, and erythema multiforme have been documented. 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 emphasize the need for proper hygiene when using the medication; patients should be instructed not to touch the dropper tip to any surface, as this may lead to contamination of the solution.

Healthcare providers should discuss the potential risks associated with tobramycin ophthalmic solution in nursing mothers. A careful decision should be made regarding whether to discontinue nursing or to discontinue the medication, weighing the importance of the drug to the mother against the potential for adverse reactions in nursing infants.

Additionally, it is crucial to inform patients that the safety and effectiveness of this medication have not been established in pediatric patients under the age of 2 months.

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°C to 25°C (36°F to 77°F) to maintain its efficacy.

Once opened, the solution can be used until the expiration date indicated on the bottle, ensuring that proper handling and storage conditions are adhered to throughout its use.

Additional Clinical Information

Patients should be advised not to touch the dropper tip to any surface to prevent contamination of the solution.

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 Belcher Pharmaceuticals, LLC. It includes detailed information about indications, dosage, contraindications, warnings, and clinical pharmacology.

View full prescribing information (PDF)