Tobramycin

Description

Tobramycin Ophthalmic Solution USP, 0.3% is a sterile topical ophthalmic antibiotic formulation designed for the treatment of external ophthalmic infections. Each mL of the solution contains tobramycin at a concentration of 0.3% (3 mg). The formulation includes inactive ingredients such as boric acid, sodium chloride, sodium sulfate, tyloxapol, sodium hydroxide and/or sulfuric acid to adjust the pH to a range of 7.0 to 8.0, and water for injection. It also contains benzalkonium chloride as a preservative at a concentration of 0.01% (0.1 mg). Tobramycin is classified as a water-soluble aminoglycoside antibiotic, effective against a broad spectrum of gram-negative and gram-positive ophthalmic pathogens. The molecular weight of tobramycin is 467.52, with a molecular formula of C18H37N5O9. The chemical name is O-{3-amino-3-deoxy-α-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 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 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 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.

Patients may exhibit sensitivity to topically applied aminoglycosides, which can manifest in varying degrees of hypersensitivity reactions. These reactions may range from localized effects to more severe systemic 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. If hypersensitivity develops while using this product, it is crucial to discontinue use and implement suitable therapeutic measures. Additionally, patients should be advised against wearing contact lenses if they exhibit signs and symptoms of a bacterial ocular infection.

Side Effects

Patients receiving tobramycin may experience a range of adverse reactions, which can be categorized by frequency and seriousness.

The most frequent adverse reactions observed in clinical trials include hypersensitivity and localized ocular toxicity. Localized ocular toxicity may manifest as lid itching and swelling, as well as conjunctival erythema. These reactions occur in less than three out of 100 patients treated with tobramycin.

In addition to the reactions noted in clinical trials, postmarketing experience has identified several additional adverse reactions. These include serious conditions such as anaphylactic reactions, Stevens-Johnson syndrome, and erythema multiforme. Furthermore, systemic aminoglycosides, including tobramycin, 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 and Parkinson's disease.

Warnings regarding hypersensitivity are significant, as sensitivity to topically applied aminoglycosides 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, including bullous reactions. If a sensitivity reaction to tobramycin ophthalmic solution 0.3% occurs, it is advised to discontinue use immediately.

Drug Interactions

There are currently no documented drug interactions associated with this medication. Additionally, there is no information available regarding interactions with laboratory tests. As such, no specific recommendations for dosage adjustments or monitoring are warranted at this time.

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 when 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 adverse effects, as individual responses to treatment may vary. Regular assessment and consideration of the patient's overall health status, comorbidities, and concurrent medications 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, 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 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 overdosage information, it is essential for healthcare professionals to remain vigilant regarding the potential for overdose with this medication. In cases where an overdose is suspected, immediate medical attention should be sought.

Healthcare providers are advised to monitor patients closely for any signs or symptoms that may indicate an overdose. These may include, but are not limited to, altered mental status, cardiovascular instability, or gastrointestinal disturbances.

Management of an overdose should be guided by the clinical presentation of the patient. Supportive care is paramount, and symptomatic treatment should be initiated as necessary. Healthcare professionals should also consider contacting a poison control center for additional guidance on the management of overdose cases.

In summary, while specific overdosage information is not available, prompt recognition and appropriate management of potential overdose symptoms are critical in ensuring patient safety.

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. Due to the limitations of animal studies in predicting 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, as this may lead to contamination of the solution. It is important to emphasize that the product is intended for topical ophthalmic use only and is not to be injected into the eye.

Patients should be informed about the potential for sensitivity to topically applied aminoglycosides, which may manifest as local effects or more generalized reactions. These reactions can include erythema, itching, urticaria, skin rash, anaphylaxis, anaphylactoid reactions, or bullous reactions. If a sensitivity reaction to tobramycin ophthalmic solution 0.3% occurs, patients should discontinue use and seek appropriate medical advice.

Providers should also discuss the risk of prolonged use of antibiotic preparations, which may lead to the overgrowth of nonsusceptible organisms, including fungi. In the event of a superinfection, appropriate therapy should be initiated.

It is crucial to inform patients about the possibility of cross-sensitivity to other aminoglycoside antibiotics. If hypersensitivity develops with this product, patients should discontinue use and consult their healthcare provider for further management.

Lastly, patients should be advised against wearing contact lenses if they exhibit signs and symptoms of a bacterial ocular infection, as this may exacerbate their condition.

Storage and Handling

The product is supplied in a configuration that ensures optimal integrity and efficacy. 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.

To maintain the quality of the product, it is essential to keep the container tightly closed when not in use. Additionally, the product must be protected from excessive heat to prevent degradation. Proper adherence to these storage and handling conditions is crucial for preserving the product's effectiveness.

Additional Clinical Information

Postmarketing experience has revealed additional adverse reactions associated with the use of the medication, including anaphylactic reactions, Stevens-Johnson syndrome, and erythema multiforme. Furthermore, systemic aminoglycosides have been linked to neurotoxicity, ototoxicity, and nephrotoxicity in patients undergoing treatment. Clinicians should also 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 Akorn. It includes detailed information about indications, dosage, contraindications, warnings, and clinical pharmacology.

View full prescribing information (PDF)