Tobrex

Description

TOBREX (tobramycin ophthalmic ointment) 0.3% is a sterile topical ophthalmic antibiotic formulation designed for the treatment of external ophthalmic infections. Each gram of TOBREX contains 0.3% tobramycin (3 mg) as the active ingredient, along with 0.5% chlorobutanol as a preservative. Inactive ingredients include mineral oil and white petrolatum. Tobramycin is classified as a water-soluble aminoglycoside antibiotic, effective against a broad spectrum of gram-negative and gram-positive ophthalmic pathogens. The molecular formula of tobramycin is C18H37N5O9, and it has a molecular weight of 467.52 g/mol. The 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

TOBREX (tobramycin ophthalmic ointment) 0.3% is indicated for the treatment of external infections of the eye and its adnexa caused by susceptible bacteria. The use of TOBREX should be accompanied by appropriate monitoring of the bacterial response to topical antibiotic therapy to ensure efficacy.

Clinical studies have demonstrated that tobramycin is safe and effective for use in pediatric patients. There are no reported teratogenic or nonteratogenic effects associated with the use of TOBREX.

Dosage and Administration

In cases of mild to moderate disease, healthcare professionals should instruct patients to apply a half-inch ribbon of TOBREX (tobramycin ophthalmic ointment) 0.3% into the affected eye(s) two to three times per day. For severe infections, the recommended dosage is to instill a half-inch ribbon into the affected eye(s) every 3 to 4 hours until improvement is observed. Following improvement, the frequency of administration should be gradually reduced prior to discontinuation of treatment.

To ensure proper application of TOBREX, the following steps should be followed:

1. The patient should tilt their head back.

2. A finger should be placed on the cheek just under the eye, gently pulling down to form a "V" pocket between the eyeball and the lower lid.

3. A small amount (approximately ½ inch) of TOBREX should be placed in the "V" pocket, ensuring that the tip of the tube does not come into contact with the eye.

4. The patient should look downward before closing their eye to facilitate even distribution of the ointment.

Contraindications

TOBREX (tobramycin ophthalmic ointment) 0.3% is contraindicated in patients with known hypersensitivity to any of its components.

Additionally, the product should not be used if the imprinted carton seals have been damaged or removed, as this may compromise the integrity of the ointment. It is also advised to avoid contact between the tube tip and any surface to prevent contamination of the ointment.

Warnings and Precautions

The use of TOBREX (tobramycin ophthalmic ointment) 0.3% necessitates careful consideration of potential warnings and precautions to ensure patient safety.

Warnings TOBREX is contraindicated for injection into the eye. Patients may exhibit sensitivity to topically applied aminoglycosides, which can manifest as localized or generalized hypersensitivity reactions. These reactions may range from erythema, itching, urticaria, and skin rash to more severe outcomes such as anaphylaxis, anaphylactoid reactions, or bullous reactions. In the event of a sensitivity reaction, it is imperative to discontinue the use of TOBREX immediately.

General Precautions As with other antibiotic preparations, prolonged use of TOBREX may lead to the overgrowth of nonsusceptible organisms, including fungi. Should a superinfection occur, appropriate therapeutic measures must be initiated. Additionally, ophthalmic ointments like TOBREX may impede corneal wound healing, necessitating caution in patients with corneal injuries. Cross-sensitivity to other aminoglycoside antibiotics is a possibility; therefore, if hypersensitivity develops while using this product, it is essential to discontinue use and provide suitable therapy. Patients should also be advised against wearing contact lenses if they exhibit signs and symptoms of ocular infections.

No specific laboratory tests are recommended for monitoring during the use of TOBREX. However, healthcare professionals should remain vigilant for any signs of hypersensitivity or superinfection and respond accordingly.

Side Effects

The most frequent adverse reactions associated with TOBREX (tobramycin ophthalmic ointment) 0.3% include hypersensitivity and localized ocular toxicity, such as 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 ointment.

In addition to the common adverse reactions, postmarketing experience has identified several additional adverse reactions. These include anaphylactic reactions, Stevens-Johnson syndrome, and erythema multiforme. Furthermore, 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.

Warnings regarding the use of TOBREX emphasize that it is not intended for injection into the eye. Some patients may experience sensitivity to topically applied aminoglycosides, with the severity of hypersensitivity reactions ranging from local effects to more generalized reactions, including erythema, itching, urticaria, skin rash, anaphylaxis, anaphylactoid reactions, or bullous reactions. In the event of a sensitivity reaction to TOBREX, it is advised to discontinue use.

Drug Interactions

There are currently no documented drug interactions associated with this medication. Additionally, there are no known 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 Tobrex (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 the use of this medication 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 adult patients. Therefore, no specific dosage adjustments are necessary for this population based on age alone.

However, healthcare providers should remain vigilant in monitoring geriatric patients for any potential age-related changes that may affect drug metabolism and response. It is essential to consider individual patient factors, including comorbidities and concurrent medications, when prescribing treatment to elderly patients.

Pregnancy

Reproduction studies in three types of animals at doses up to thirty-three 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 TOBREX® (tobramycin ophthalmic ointment) 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 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 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, increased severity of known side effects, altered mental status, or any unusual physiological responses.

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, healthcare professionals should exercise caution, monitor for symptoms, and provide appropriate supportive care in the event of an overdose.

Nonclinical Toxicology

Reproduction studies conducted in three animal species at doses up to thirty-three 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, including anaphylactic reactions, Stevens-Johnson syndrome, and erythema multiforme. Reports of neurotoxicity, ototoxicity, and nephrotoxicity have been noted in patients receiving systemic aminoglycoside therapy. Furthermore, it has been observed 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.

Patient Counseling

Patients should be advised not to wear contact lenses if they exhibit any signs or symptoms of ocular infections. It is important to instruct patients to avoid touching the tube tip to any surface, as this may lead to contamination of the ointment. Additionally, patients should be informed not to use the product if the imprinted carton seals have been damaged or removed.

Healthcare providers should discuss the potential risks associated with TOBREX® (tobramycin ophthalmic ointment) 0.3% in nursing infants. A careful decision should be made regarding whether to discontinue nursing or to discontinue the drug, considering the importance of the medication to the mother’s health.

Storage and Handling

TOBREX (tobramycin ophthalmic ointment) 0.3% is supplied in a tube format. The product should be stored at a temperature range of 2°C to 25°C (36°F to 77°F) to maintain its efficacy.

Once opened, TOBREX can be used until the expiration date indicated on the tube. It is important to ensure that the product is kept within the specified temperature range and handled according to the guidelines to preserve its quality and 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.

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 Tobrex as submitted by Novartis Pharmaceuticals Corporation. It includes detailed information about indications, dosage, contraindications, warnings, and clinical pharmacology.

View full prescribing information (PDF)