Recommended Dosing for Tobradex (Tobramycin and Dexamethasone)
For ocular conditions requiring Tobradex, instill 1-2 drops into the affected eye(s) every 4-6 hours; for severe infections, dosing can be increased to every 2 hours during the initial 24-48 hours, then tapered as improvement occurs.
Formulations and Composition
Tobradex is available in multiple formulations:
- Tobradex suspension: tobramycin 0.3% and dexamethasone 0.1%
- Tobradex ST suspension: tobramycin 0.3% and dexamethasone 0.05% (improved formulation with xanthan gum)
- Tobradex ointment: tobramycin 0.3% and dexamethasone 0.1%
Specific Dosing Guidelines by Formulation
Tobradex Suspension
- Initial/Severe infections: 1-2 drops every 2 hours while awake for the first 24-48 hours
- Maintenance: 1-2 drops every 4-6 hours after improvement begins
- Duration: Typically 7-10 days, based on clinical response
Tobradex ST Suspension
- Same dosing schedule as standard suspension, but with improved ocular distribution and bactericidal activity 1
- The ST formulation demonstrates superior anti-inflammatory and bactericidal properties compared to standard Tobradex 2
Tobradex Ointment
- Apply a small amount (½ inch ribbon) into the conjunctival sac 2-3 times daily
- For severe infections, can be used every 3-4 hours initially, then reduced as improvement occurs
Pediatric Dosing
- Children (all ages): Same dosing as adults - 1-2 drops every 4-6 hours, increasing to every 2 hours for severe infections 3
- Tobradex has been studied in pediatric populations and demonstrates efficacy and safety 3
Clinical Applications
Tobradex is indicated for:
- Bacterial conjunctivitis
- Blepharitis with bacterial component 4
- Post-surgical inflammation where risk of bacterial infection exists 5
- Bacterial keratitis (as part of treatment regimen) 6
Advantages of Tobradex ST Formulation
The newer Tobradex ST formulation offers several advantages:
- Uses novel suspension technology to reduce viscosity and prevent settling 1
- Provides 8.3-fold increase in tobramycin concentration in tear film compared to original formulation 1
- Achieves up to 12.5-fold greater concentrations of both active ingredients in ocular tissues 1
- Demonstrates improved bactericidal activity against resistant organisms 1
Important Administration Guidelines
- Shake well before using (especially important for suspension formulations)
- Wait at least 5 minutes between applications of different eye medications
- After instillation, apply gentle pressure to the inner corner of the eye for 1-2 minutes to minimize systemic absorption
- For post-surgical use, administration typically begins 24 hours before surgery and continues through the post-operative period 5
Monitoring and Duration of Treatment
- Most conditions require 7-10 days of treatment
- For post-surgical inflammation, treatment may continue for up to 21 days 5
- Monitor for increased intraocular pressure with prolonged use
- Discontinue if signs of hypersensitivity develop
Common Pitfalls to Avoid
- Inadequate shaking of suspension: Failure to shake the bottle well before each use can result in inconsistent dosing
- Prolonged use without monitoring: Extended use beyond 10-14 days without ophthalmologic supervision can increase risk of steroid-related complications
- Contamination of bottle tip: Allowing the dropper tip to touch any surface can introduce contamination
- Premature discontinuation: Stopping therapy when symptoms improve but before infection is fully resolved can lead to recurrence
Remember that Tobradex combines an antibiotic (tobramycin) with a corticosteroid (dexamethasone), making it appropriate only for conditions where both bacterial infection and inflammation are present.