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 3 mg of tobramycin as the active ingredient, along with 0.1 mg of benzalkonium chloride as a preservative. Inactive ingredients include boric acid, sodium sulfate decahydrate, sodium chloride, tyloxapol, sodium hydroxide and/or sulfuric acid (for pH adjustment), and water for injection.

The solution has a pH range of 7.0 to 8.0 and an osmolality of 260 to 320 mOsm/kg. Tobramycin, a water-soluble aminoglycoside antibiotic, exhibits activity against a broad spectrum of gram-negative and gram-positive ophthalmic pathogens. The chemical structure of tobramycin is characterized by a molecular weight of 467.52 and a molecular formula of C18H37N5O9. Its chemical name is 0-{3-amino-3-deoxy-α-D-gluco-pyranosyl-(1→4)}-0-{2,6-diamino-2,3,6-trideoxy-α-D-ribohexo-pyranosyl-(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 in the ocular region.

Appropriate monitoring of bacterial response to topical antibiotic therapy should accompany the use of tobramycin ophthalmic solution to ensure therapeutic efficacy and safety.

Clinical studies have demonstrated that tobramycin is safe and effective for use in pediatric patients, supporting its application in children with indicated conditions.

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 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.

Cross-sensitivity to other aminoglycoside antibiotics is a possibility; therefore, if hypersensitivity develops with this product, it is crucial to discontinue use and implement suitable therapeutic measures. Additionally, patients should be counseled against wearing contact lenses if they exhibit signs and symptoms of a bacterial ocular infection to prevent exacerbation of their condition.

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 were observed in less than three out of 100 patients treated with the solution.

In addition to the common adverse reactions, postmarketing experience has revealed more serious events, including anaphylactic reactions, Stevens-Johnson syndrome, and erythema multiforme. It is important to note that sensitivity to topically applied aminoglycosides, such as 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. Should a sensitivity reaction occur, discontinuation of Tobramycin ophthalmic solution is advised.

Furthermore, additional adverse reactions associated with systemic aminoglycosides may also be relevant, including neurotoxicity, ototoxicity, nephrotoxicity, and the aggravation of muscle weakness in patients with known or suspected neuromuscular disorders, such as myasthenia gravis or Parkinson’s disease, due to potential effects on neuromuscular function.

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 Ophthalmic Solution, 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 have been evaluated in clinical studies, and no overall differences in safety or effectiveness have been observed when compared to younger patients. Therefore, specific dosage adjustments based solely on age are not necessary.

However, it is important for healthcare providers to remain vigilant when prescribing to geriatric patients, as individual responses may vary. Continuous monitoring for any potential adverse effects or changes in therapeutic response is recommended to ensure optimal treatment outcomes in this population.

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 drug 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

Patients with hepatic impairment have not been specifically studied in relation to the use of this medication. Consequently, there are no 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

In the context of overdosage, it is important to note that there is no specific information regarding overdosage provided in the available sections of the drug insert.

Healthcare professionals are advised to exercise caution and consider the potential implications of an overdose, even in the absence of detailed guidance. In the event of suspected overdosage, it is recommended that healthcare providers monitor the patient closely for any adverse effects and manage symptoms as they arise.

Given the lack of specific overdosage information, supportive care should be the primary focus, and consultation with a poison control center or a medical toxicologist may be warranted to guide further management.

Nonclinical Toxicology

Reproduction studies conducted in three animal species at doses up to 33 times the normal human systemic dose have shown 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. Healthcare providers should emphasize the importance of maintaining proper hygiene when using the medication, specifically instructing patients not to touch the dropper tip to any surface, as this may lead to contamination of the solution.

In the event that a patient experiences a sensitivity reaction to Tobramycin ophthalmic solution, 0.3%, they should be instructed to discontinue use immediately and consult their healthcare provider. It is also crucial to inform patients that prolonged use of this medication may result in the overgrowth of nonsusceptible organisms, including fungi. Should a superinfection occur, appropriate therapy must be initiated.

Additionally, healthcare providers should discuss the implications of the medication for nursing mothers. A decision should be made regarding whether to discontinue nursing the infant or to discontinue the drug, taking into account the importance of the medication to the mother’s health.

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. It is essential to handle the product with care to prevent contamination and ensure optimal performance.

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 associated with the use of the product, including anaphylactic reactions, Stevens-Johnson syndrome, and erythema multiforme.

FDA Insert (PDF)

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

View full prescribing information (PDF)