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, which is the active ingredient, along with inactive components including boric acid, sodium chloride, sodium sulfate, tyloxapol, sodium hydroxide and/or sulfuric acid for pH adjustment (7.0 to 8.0), and water for injection. The formulation also includes 0.1 mg of benzalkonium chloride as a preservative.

Tobramycin is classified as a water-soluble aminoglycoside antibiotic, exhibiting 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 O-{3-amino-3-deoxy-β-D-gluco-pyranosyl (1→4)}-O-{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 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 to ensure optimal therapeutic outcomes.

There are no teratogenic or nonteratogenic effects associated with the use of 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.

Healthcare professionals are advised to ensure proper technique during administration to maximize therapeutic efficacy and minimize potential side effects.

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 conjunctivitis, as this may exacerbate the condition.

Warnings and Precautions

Topical ophthalmic use is the only approved application for this medication; it is strictly contraindicated for injection into the eye. Patients may experience sensitivity to topically applied aminoglycosides, which can manifest as a range of hypersensitivity reactions. These reactions may vary in severity, presenting as local effects or 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. Additionally, cross-sensitivity to other aminoglycoside antibiotics may be observed. If hypersensitivity develops while using this product, it is crucial to discontinue use and implement suitable therapeutic measures. Patients should also be advised against wearing contact lenses if they exhibit signs and symptoms of bacterial conjunctivitis to prevent exacerbation of their condition.

No specific laboratory tests are recommended for monitoring during the use of this medication. However, healthcare professionals should remain vigilant for any signs of adverse reactions or superinfection and manage them accordingly.

Side Effects

Most frequent adverse reactions observed in patients treated with tobramycin include hypersensitivity and localized ocular toxicity. Localized ocular toxicity may manifest as lid itching, swelling, and conjunctival erythema, occurring in less than three of 100 patients.

In the postmarketing experience, more serious adverse reactions have been reported, including anaphylactic reactions, Stevens-Johnson syndrome, and erythema multiforme. Additionally, systemic aminoglycosides have been associated with neurotoxicity, ototoxicity, and nephrotoxicity. It is important to note 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 effects on neuromuscular function.

Patients may experience sensitivity to topically applied aminoglycosides, with the severity of hypersensitivity reactions ranging from local effects to more generalized reactions. These reactions can include erythema, itching, urticaria, skin rash, and in severe cases, anaphylaxis or anaphylactoid reactions, including bullous reactions. If a sensitivity reaction to tobramycin ophthalmic solution 0.3% occurs, it is advised to discontinue use.

Drug Interactions

Cross-sensitivity to other aminoglycoside antibiotics may occur. In the event of hypersensitivity reactions to this product, it is advised to discontinue use and initiate appropriate therapeutic measures.

Aminoglycosides have the potential to exacerbate muscle weakness in patients with known or suspected neuromuscular disorders, including myasthenia gravis and Parkinson's disease, due to their effects on neuromuscular function. Monitoring of neuromuscular status is recommended in these patients to mitigate risks associated with the use of aminoglycosides.

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. 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 compared to younger adult patients. Therefore, no specific dosage adjustments are necessary for this population.

However, healthcare providers should remain vigilant in monitoring geriatric patients for any potential age-related changes that may influence 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, which is classified as Pregnancy Category B. However, there are no adequate and well-controlled studies in pregnant women. Given that 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, 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 data regarding dosage adjustments, special monitoring, or safety considerations. Therefore, healthcare professionals should exercise caution when prescribing this medication to patients with reduced kidney function, as the lack of information necessitates careful clinical judgment and monitoring.

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 from an overdose. Symptoms can vary widely depending on the substance involved and the individual patient's response.

In the event of an overdose, immediate medical attention should be sought. Healthcare providers should initiate supportive care, which may include maintaining airway patency, ensuring adequate ventilation, and monitoring vital signs.

If available, the use of specific antidotes or treatments should be considered based on the substance involved and the clinical presentation. Consultation with a poison control center or a medical toxicologist may provide additional guidance on the management of overdose cases.

Documentation of the incident, including the substance, amount ingested, and time of exposure, is crucial for effective treatment and follow-up care.

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

Healthcare providers should advise patients to avoid touching the dropper tip to any surface to prevent contamination of the solution. It is important to inform patients that they should not wear contact lenses if they exhibit signs and symptoms of bacterial conjunctivitis, as this may exacerbate their condition.

Providers should discuss the potential risks associated with tobramycin, particularly for nursing mothers. A careful decision should be made regarding whether to discontinue nursing or the medication itself, considering the importance of the drug to the mother and the potential for adverse reactions in nursing infants.

Additionally, healthcare providers should communicate that the safety and effectiveness of this medication in pediatric patients under the age of 2 months have not been established. Patients should be instructed to discontinue use if they experience any sensitivity reactions to tobramycin ophthalmic solution 0.3%.

It is also essential to inform patients that prolonged use of the medication may lead to the overgrowth of nonsusceptible organisms, including fungi. In the event of a superinfection, appropriate therapy should be initiated promptly.

Storage and Handling

The product is supplied in a container that must be kept tightly closed to maintain its integrity. It should be stored at a temperature range of 20° to 25°C (68° to 77°F), in accordance with USP Controlled Room Temperature guidelines. Additionally, it is essential to protect the product from excessive heat to ensure optimal stability and efficacy.

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 bacterial conjunctivitis.

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. 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 MWI. It includes detailed information about indications, dosage, contraindications, warnings, and clinical pharmacology.

View full prescribing information (PDF)