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 components 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 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 ocular infection, as this may exacerbate the condition.

Warnings and Precautions

Topical ophthalmic use of Tobramycin ophthalmic solution, 0.3% is strictly indicated; it is not intended 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, it is imperative to discontinue use of the product 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 Tobramycin, the product should be discontinued, and suitable therapeutic measures should be taken. Patients should also be advised against wearing contact lenses if they present with signs and symptoms indicative of a bacterial ocular infection.

No specific laboratory tests have been identified for monitoring during the use of Tobramycin ophthalmic solution, 0.3%. However, healthcare professionals should remain vigilant for any adverse reactions and manage them accordingly.

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.

In addition to the common adverse reactions, there are notable postmarketing experiences that include serious conditions such as anaphylactic reactions, Stevens-Johnson syndrome, and erythema multiforme. These serious adverse reactions highlight the importance of monitoring patients for any signs of hypersensitivity.

Furthermore, additional adverse reactions associated with systemic aminoglycosides may also be relevant. These include neurotoxicity, ototoxicity, and nephrotoxicity. It is important to note that Tobramycin may exacerbate muscle weakness in patients with known or suspected neuromuscular disorders, such as myasthenia gravis and Parkinson’s disease.

Patients should be informed that sensitivity to topically applied aminoglycosides, including Tobramycin, may occur. 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. If any sensitivity reaction occurs, it is advised to discontinue the use of Tobramycin ophthalmic solution.

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, and dosage adjustments may be necessary based on clinical assessment.

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, defined as those aged 65 years and older, have not demonstrated any overall differences in safety or effectiveness compared to younger patients. Therefore, no specific dosage adjustments are necessary for this population. However, it is essential for healthcare providers to remain vigilant in monitoring geriatric patients for any potential age-related changes that may influence individual responses to treatment. Regular assessment and consideration of the overall health status of elderly patients are recommended 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 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 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

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

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 unusual symptoms that may arise following administration.

In the event of suspected overdosage, standard supportive measures should be implemented. This includes ensuring the patient's airway is clear, providing oxygen if necessary, and monitoring vital signs. Healthcare providers should be prepared to manage any symptoms that may occur, although specific symptoms related to overdosage have not been detailed.

As there are no established guidelines for the management of overdosage with this medication, it is recommended that healthcare professionals consult local poison control centers or relevant medical authorities for further guidance. Continuous assessment and supportive care remain paramount in managing any potential overdosage scenarios.

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 touch the dropper tip to any surface, as this may contaminate the solution and compromise its effectiveness. It is important to inform patients that they should refrain from wearing contact lenses if they exhibit signs and symptoms of a bacterial ocular infection, as this could exacerbate their condition.

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 the medication itself, weighing the importance of the drug to the mother against the potential for adverse reactions in nursing infants.

Additionally, it is crucial to communicate that the safety and effectiveness of tobramycin ophthalmic solution have not been established in pediatric patients under the age of 2 months. If patients experience any sensitivity reactions to the medication, they should be instructed to discontinue use immediately and consult their healthcare provider.

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 important to handle the product with care to prevent contamination and ensure optimal performance.

Additional Clinical Information

Patients should be counseled on the importance of not touching the dropper tip to any surface to avoid 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 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 Inc.. It includes detailed information about indications, dosage, contraindications, warnings, and clinical pharmacology.

View full prescribing information (PDF)