Tobramycin

Pharmacologic Category

Antibiotic, Aminoglycoside; Antibiotic, Ophthalmic

Dosing: Adult

Ocular infections: Ophthalmic:

Ointment: Apply half-inch ribbon into affected eye(s) 2 or 3 times daily for mild to moderate infections; for severe infections, apply every 3 to 4 hours until improvement (then reduce prior to discontinuation).

Solution: Instill 1 to 2 drops into affected eye(s) every 4 hours for mild to moderate infections; for severe infections, instill 2 drops every hour until improvement (then reduce prior to discontinuation).

Viscous solution (Tobrexan [Canadian product]): Instill 1 drop into affected eye(s) 2 times daily for 7 days for mild to moderate infections; for severe infections, instill 1 drop 4 times daily on day 1 and then 2 times daily for duration of treatment period.

* See Dosage and Administration in AHFS Essentials for additional information.

Dosing: Renal Impairment: Adult

There are no dosage adjustments provided in the manufacturer’s labeling. However, dosage adjustment unlikely due to low systemic absorption.

Dosing: Hepatic Impairment: Adult

There are no dosage adjustments provided in the manufacturer’s labeling. However, dosage adjustment unlikely due to low systemic absorption.

Dosing: Pediatric

Ocular infections: Ophthalmic: Infants ≥2 months, Children, and Adolescents:

Ointment:

Mild to moderate infections: Apply 1/2 inch ribbon into the affected eye(s) 2 to 3 times daily

Severe infections: Apply 1/2 inch ribbon into the affected eye(s) every 3 to 4 hours initially until improvement, then reduce to less frequent intervals prior to discontinuation

Solution:

Mild to moderate infections: Instill 1 to 2 drops into the affected eye(s) every 4 hours

Severe infections: Instill 2 drops into the affected eye(s) every hour initially until improvement, then reduce to less frequent intervals prior to discontinuation

Dosing: Renal Impairment: Pediatric

There are no dosage adjustments provided in the manufacturer’s labeling; however, dosage adjustment unlikely due to low systemic absorption.

Dosing: Hepatic Impairment: Pediatric

There are no dosage adjustments provided in the manufacturer’s labeling; however, dosage adjustment unlikely due to low systemic absorption.

Use: Labeled Indications

Ocular infections: Treatment of external infections of the eye and its adnexa caused by susceptible bacteria.

* See Uses in AHFS Essentials for additional information.

Class and Related Monographs

Ophthalmic Antibiotics

Administration: Ophthalmic

For topical ophthalmic use only; not for injection into the eye. Contact lenses should not be worn during treatment of ophthalmic infections. Avoid contaminating the applicator tip with affected eye(s).

Ointment: Apply into conjunctival sac(s) of eye; patient should look downward before closing eye.

Administration: Pediatric

For topical ophthalmic use only; not for injection into the eye. Contact lenses should not be worn during treatment of ophthalmic infections. Avoid contact of tube or bottle tip with skin or eye.

Ointment: Apply into conjunctival sac(s) of eye; patient should look downward before closing eye

Solution: Apply gentle pressure to lacrimal sac during and immediately following instillation (1 minute) or instruct patient to gently close eyelid after administration, to decrease systemic absorption of ophthalmic drops (Urtti 1993; Zimmerman 1982)

Storage/Stability

Store at 2°C to 25°C (36°F to 77°F).

Medication Patient Education with HCAHPS Considerations

What is this drug used for?

• It is used to treat eye infections.

Other side effects of this drug: Talk with your doctor right away if you have any of these signs of:

• Vision changes

• Eye pain

• Severe eye irritation

• Signs of a significant reaction like wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat.

Note: This is not a comprehensive list of all side effects. Talk to your doctor if you have questions.

Consumer Information Use and Disclaimer: This information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not specific medical advice and does not replace information you receive from the healthcare provider. You must talk with the healthcare provider for complete information about the risks and benefits of using this medicine.

Medication Safety Issues

Sound-alike/look-alike issues:

Contraindications

Hypersensitivity to tobramycin or any component of the formulation

Canadian labeling: Additional contraindications (not in US labeling): Known hypersensitivity to any aminoglycoside

Warnings/Precautions

Concerns related to adverse effects:

• Hypersensitivity reactions: Sensitivity to topically applied aminoglycosides and cross sensitivity to other aminoglycosides antibiotics may occur; discontinue use if hypersensitivity develops.

• Superinfection: Prolonged use may lead to overgrowth of nonsusceptible organisms, including fungi. If superinfection is suspected, institute appropriate alternative therapy.

Special populations:

• Contact lens wearers: Some products may contain benzalkonium chloride or benzododecinium bromide which may be absorbed by soft contact lenses; contact lenses should not be worn during treatment of ophthalmologic infections.

Other warnings/precautions:

• Appropriate use: For topical application to the eye only; not for injection. To avoid contamination, do not touch tip of container to any surface.

* See Cautions in AHFS Essentials for additional information.

Geriatric Considerations

Evaluate the patient's or caregiver's ability to safely administer the correct dose of ophthalmic medication.

Pregnancy Risk Factor

B

Pregnancy Considerations

Adverse events have not been observed in animal reproduction studies. The amount of tobramycin available systemically following topical application of the ophthalmic drops is undetectable (<0.2 mcg/mL) (Filatov 1994). If ophthalmic agents are needed during pregnancy, the minimum effective dose should be used in combination with punctal occlusion to decrease systemic absorption (Samples 1988).

Breast-Feeding Considerations

The amount of tobramycin available systemically following topical application of the ophthalmic drops is undetectable (<0.2 mcg/mL) (Filatov 1994). If ophthalmic agents are needed in lactating women, the minimum effective dose should be used in combination with punctal occlusion to decrease systemic absorption (Samples 1988).

Due to the potential for serious adverse reactions in the nursing infant, the manufacturer recommends a decision be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of treatment to the mother.

Briggs' Drugs in Pregnancy & Lactation

• Tobramycin Ophthalmic

Adverse Reactions

<1%, postmarketing, and/or case reports: Conjunctival erythema, eyelid edema, eyelid pruritus

* See Cautions in AHFS Essentials for additional information.

Allergy and Idiosyncratic Reactions

• Aminoglycoside Allergy

Metabolism/Transport Effects

None known.

Drug Interactions Open Interactions

There are no known significant interactions.

Dosage Forms: US

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Ointment, Ophthalmic:

Tobrex: 0.3% (3.5 g)

Solution, Ophthalmic:

Tobrex: 0.3% (5 mL)

Generic: 0.3% (5 mL)

Dosage Forms: Canada

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Ointment, Ophthalmic:

Tobrex: 0.3% (3.5 g) [contains chlorobutanol (chlorobutol)]

Solution, Ophthalmic:

Crown Ak-Tobra: 0.3% (5 mL)

Tobrex: 0.3% (5 mL) [contains benzalkonium chloride]

Generic: 0.3% (5 mL)

Anatomic Therapeutic Chemical (ATC) Classification

• S01AA12

Generic Available (US)

May be product dependent

Pricing: US

Ointment (Tobrex Ophthalmic)

0.3% (per gram): $73.49

Solution (Tobramycin Ophthalmic)

0.3% (per mL): $2.77 - $6.80

Solution (Tobrex Ophthalmic)

0.3% (per mL): $24.50

Disclaimer: A representative AWP (Average Wholesale Price) price or price range is provided as reference price only. A range is provided when more than one manufacturer's AWP price is available and uses the low and high price reported by the manufacturers to determine the range. The pricing data should be used for benchmarking purposes only, and as such should not be used alone to set or adjudicate any prices for reimbursement or purchasing functions or considered to be an exact price for a single product and/or manufacturer. Medi-Span expressly disclaims all warranties of any kind or nature, whether express or implied, and assumes no liability with respect to accuracy of price or price range data published in its solutions. In no event shall Medi-Span be liable for special, indirect, incidental, or consequential damages arising from use of price or price range data. Pricing data is updated monthly.

Mechanism of Action

Interferes with bacterial protein synthesis by binding to 30S ribosomal subunit resulting in a defective bacterial cell membrane

Pharmacodynamics/Kinetics

Absorption: Systemic absorption: Undetectable (<0.2 mcg/mL) (Filatov 1994); tear film exposure and time above MIC90 are significantly greater with viscous ophthalmic solution [Canadian product] (Tobrexan Canadian product labeling).

Local Anesthetic/Vasoconstrictor Precautions

No information available to require special precautions

Effects on Dental Treatment

No significant effects or complications reported

Effects on Bleeding

No information available to require special precautions

Index Terms

Tobramycin Sulfate

FDA Approval Date

December 13, 1984

References

Filatov V, Alexandrakis G, Rainey PM, Perazella MA, Gloor P. No detectable systemic absorption of topically administered ophthalmic tobramycin. Am J Ophthalmol. 1994;117(3):402-403.[PubMed 8129019 ]

Samples JR, Meyer SM. Use of ophthalmic medications in pregnant and nursing women. Am J Ophthalmol. 1988;106(5):616-623.[PubMed 2903673]

Tobrex ointment (tobramycin ophthalmic) [prescribing information]. Fort Worth, TX: Alcon Laboratories, Inc; April 2018.

Tobrex ointment and solution (tobramycin ophthalmic) [product monograph]. Dorval, Quebec, Canada: Novartis Pharmaceuticals Canada Inc; February 2020.

Tobrex solution (tobramycin ophthalmic) [prescribing information]. Fort Worth, TX: Alcon Laboratories, Inc; April 2018.

Tobrexan viscous solution (tobramycin ophthalmic) [product monograph]. Dorval, Quebec, Canada: Novartis Pharmaceuticals Canada Inc; October 2017.

Urtti A, Salminen L. Minimizing systemic absorption of topically administered ophthalmic drugs. Surv Ophthalmol. 1993;37(6):435-456.[PubMed 8100087]

Zimmerman TJ, Kooner KS, Kandarakis AS, Ziegler LP. Improving the therapeutic index of topically applied ocular drugs. Arch Ophthalmol. 1984;102(4):551-553.[PubMed 6704011]

Brand Names: International

Avazir (EG); Bralifex (ET, ID); Cleo (TW); Consac (PH); Eyebrex (PH); Gotabiotic (AR, CR, DO, GT, HN, NI, PA, SV); Isenia (CR, DO, GT, HN, NI, PA, SV); Isotic Tobryne (ID); Marunol (CR, DO, GT, HN, NI, PA, SV); Nebra (LK); Oculotob (EG); Ocuracin (KR); Ocusyn (LK, SG); Oftalbrax (AR); Okle (KR); T Mycin (BD); Tobacin (ET, IN); Toberan (KR); Tobra (BD, KR); Tobra-Day (AU); Tobra-V (PH); Tobracin (JO, QA); Tobragan (BR, CL); Tobral (EC, IT); Tobramaxin (DE); Tobramex (PH); Tobrased (ET); Tobrasol (VE); Tobrastill (LB); Tobravisc (GB); Tobre (KR); Tobrex (AE, AT, AU, BB, BE, BF, BG, BH, BJ, BR, CH, CI, CL, CN, CO, CR, CY, CZ, DK, DO, EE, EG, ES, ET, FI, FR, GH, GM, GN, GR, GT, HK, HN, HR, IL, IQ, IR, JO, KE, KW, LB, LK, LR, LT, LU, LV, LY, MA, ML, MR, MT, MU, MW, MY, NE, NG, NI, NL, NO, NZ, OM, PA, PE, PK, PL, PT, PY, QA, RO, RU, SA, SC, SD, SE, SI, SK, SL, SN, SV, SY, TH, TN, TR, TW, TZ, UA, UG, UY, VE, VN, YE, ZA, ZM, ZW); Tobrimin (DO); Tobrin (AE, BH, CY, EG, IQ, IR, JO, KW, LB, LY, OM, QA, SA, SY, YE); Tocin (TW); Tomidrop (VN); Tomracin (PH); Trazil ofteno (EC)

Last Updated 3/11/20