Tobramycin

Description

Tobramycin ophthalmic solution 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. Inactive ingredients include boric acid, sodium sulfate, 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 260-320 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 and should be used in conjunction with appropriate monitoring of the bacterial response to therapy.

Clinical studies have demonstrated that tobramycin ophthalmic solution 0.3% is safe and effective for use in pediatric patients.

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 0.3% is contraindicated in patients with a known hypersensitivity to any of its components. Use in these patients may lead to severe allergic reactions.

Warnings and Precautions

Topical ophthalmic medications are intended solely for external use and must not be injected into the eye. Healthcare professionals should be aware that sensitivity to topically applied aminoglycosides, including tobramycin, may occur in some patients.

The severity of hypersensitivity reactions can range from localized effects to more generalized responses. These may include erythema, itching, urticaria, skin rash, and in severe cases, 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. Monitoring for signs of hypersensitivity is recommended to ensure patient safety and to facilitate timely intervention if adverse reactions occur.

Side Effects

The most frequent adverse reactions associated with tobramycin ophthalmic solution 0.3% include hypersensitivity and localized ocular toxicity, which encompasses lid itching and swelling as well as conjunctival erythema. These reactions are reported to occur in less than three out of 100 patients treated with the solution.

In addition to the common adverse reactions, postmarketing experience has identified further adverse reactions, including anaphylactic reactions, Stevens-Johnson syndrome, and erythema multiforme. It is important to note that sensitivity to topically applied aminoglycosides may occur in some patients, with the severity of hypersensitivity reactions ranging from local effects to more generalized reactions such as erythema, itching, urticaria, skin rash, and in severe cases, anaphylaxis or anaphylactoid reactions. Should a sensitivity reaction to tobramycin ophthalmic solution 0.3% occur, discontinuation of the product is advised.

Additional adverse reactions reported with systemic aminoglycosides include neurotoxicity, ototoxicity, and nephrotoxicity. Furthermore, aminoglycosides may exacerbate muscle weakness in patients with known or suspected neuromuscular disorders, such as myasthenia gravis and Parkinson's disease.

Prolonged use of tobramycin ophthalmic solution 0.3% 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 this product, it is recommended to discontinue use and implement suitable therapy.

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 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

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 clinical judgment when considering the use of this medication in patients with liver problems, as the absence of specific guidance necessitates careful evaluation of the patient's overall health status and liver function.

Overdosage

In the absence of specific information regarding overdosage, healthcare professionals are advised to exercise caution when administering the medication. It is essential to monitor patients closely for any signs of adverse effects or symptoms that may arise from excessive dosing.

In the event of suspected overdosage, immediate medical attention should be sought. Healthcare providers should implement supportive measures as necessary, which may include symptomatic treatment and monitoring of vital signs.

Due to the lack of detailed overdosage information, it is recommended that healthcare professionals refer to established clinical guidelines and protocols for managing overdose situations relevant to the specific medication in question. Additionally, contacting a poison control center may provide further guidance on appropriate management strategies.

Continued vigilance and patient assessment are crucial in mitigating potential risks associated with overdosage.

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

Healthcare providers should discuss the potential risks associated with tobramycin ophthalmic solution 0.3% in nursing mothers. A careful decision should be made regarding whether to discontinue nursing or the medication, considering the importance of the drug to the mother and the potential for adverse reactions in nursing infants.

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

Storage and Handling

Tobramycin ophthalmic solution 0.3% is supplied in a container that allows for easy dispensing. 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 ensure that the container is properly sealed when not in use to prevent contamination and preserve the integrity of the product.

Additional Clinical Information

In patients with mild to moderate disease, the recommended administration is 1 or 2 drops instilled into the affected eye(s) every 4 hours. For severe infections, clinicians should instill 2 drops into the eye(s) hourly until improvement is observed, after which the frequency should be reduced prior to discontinuation of treatment.

Patients should be counseled on proper administration techniques, including avoiding contact with the dropper tip 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. Postmarketing 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, and may exacerbate muscle weakness in individuals with neuromuscular disorders such as myasthenia gravis or Parkinson's disease.

FDA Insert (PDF)

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

View full prescribing information (PDF)