Tobramycin Eye Drops & Ointment (Tobrex) is an aminoglycoside antibiotic that is used for treating bacterial infections of the eyes.

Tobramycin Uses:

• Ocular infections:

  • It is used as a topical ophthalmic solution or ointment for the treatment of external infections of the eye and its adnexa caused by susceptible bacteria.

Tobramycin Dose in Adults

Tobramycin eye drops and ointment dose in the treatment of Ocular infections: Ophthalmic:

• Ointment:

  • Apply 1/2 inch ribbon into the affected eye(s) twice or thrice daily for mild to moderate infections;
  • For severe infections, apply every 3 to 4 hours until improvement, then reduce the frequency of administration before treatment discontinuation.

• Solution:

  • Instill 1 to 2 drops into the affected eye(s) every 4 hours for mild to moderate infections;
  • For severe infections, instill two drops hourly until improvement then reduce the frequency of administration before treatment discontinuation.

• Viscous solution (Tobrexan [Canadian product]):

  • For mild to moderate infections, use one drop twice day for seven days to the afflicted eye(s).
  • For the course of the treatment term, administer one drop four times per day on day 1 for severe infections

Tobramycin Dose in Children

Tobramycin Dose in the treatment of Ocular infections: 

• Infants ≥2 months, Children, and Adolescents:

  • Ointment:

    • Mild to moderate infections:
      • Apply 1/2 inch ribbon into the affected eye(s) twice or thrice daily.
    • Severe infections:
      • Apply 1/2 inch ribbon into the affected eye(s) every 3 to 4 hours initially until improvement, then reduce the frequency of administration before 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 hourly initially until clinical improvement is noted, then reduce the frequency of administration.

Pregnancy Risk Factor B

• Adverse foetal outcomes in animal reproduction studies have not yet been documented because there is little to no systemic absorption.
• To minimize systemic absorption, the treatment should be limited to a short duration. Punctal occlusion should be used to reduce the dose.

Use of Tobramycin while breastfeeding

• The risk of systemic absorption after ophthalmic administration are very low. 
• To minimize systemic absorption, the treatment duration should be kept as short as possible.
• Punctal occlusion should be used to reduce the effectiveness of the dose.
• However, the manufacturer recommends that you stop breastfeeding.
• This is based on the risk to your baby and the benefits for your mother.

Dose in Kidney Disease:

• The manufacturer's labelling does not mention dosage modifications.
• However, dosage adjustment is not required due to minimal systemic absorption.

Dose in Liver disease:

• The manufacturer's labelling does not mention dosage modifications.
• However, dosage adjustment is not required due to minimal systemic absorption.

Side effects to Tobramycin eye drops and ointments:

• Ocular:
  • itching
  • burning
  • stinging
  • photosensitivity
  • blurred vision
  • eye discomfort

Contraindications to Tobramycin eye drops and eye ointment:

Allergy reactions to tobramycin and any component of the formulation Canadian labeling: Additional contraindications not in US labeling

• Allergies to aminoglycosides are known

Warnings and precautions

• Hypersensitivity reactions

  • hypersensitivity to topically applied aminoglycosides could be cross-sensitive to other aminoglycosides. 
  • Patients with a hypersensitivity reaction to any aminoglycoside should be advised to avoid unnecessary exposure.

• Superinfection

  • If used prolonged it can lead to superinfections, including fungal infections of your eyes. 
  • signs of superinfections should be closely monitored. If necessary, treatment should be initiated immediately.

Monitoring Parameters:

None mentioned. Monitor the response to treatment. Avoid prolonged use.

How to administer Tobramycin eye drops and ointment?

• It is intended for topical ophthalmic use only.
• Systemic administration should be avoided. It is not for intraocular injection.
• Patients should be asked not to wear contact lenses during ophthalmic infections.
• Furthermore, the tip of the dropper or the applicator should not be touched by the surrounding surfaces or the eye to avoid contaminating it.

Ointment:

• Apply the ointment into the conjunctival sac of the infected eye.
• After applying the ointment, ask the patient to look down and then close the eyes.

Mechanism of action of Tobramycin (Ophthalmic):

• It binds with the 30S subunit of the ribosomal ribosomal subunit, inhibiting bacterial protein synthesis.
• This results in membrane disruption and bacterial cell damage.

Absorption:

• Systemic absorption: Undetectable (0.2 mg/mL);
• Viscous ophthalmic solutions [Canadian product] have a significantly higher tear film exposure (Tobrexan Canadian product labeling).

International Brand Names of Tobramycin (Ophthalmic):

• APO-Tobramycin
• Crown Ak-Tobra
• PMS-Tobramycin
• SANDOZ Tobramycin
• Tobrex
• Avazir
• Bralifex
• Cleo
• Consac
• Eyebrex
• Gotabiotic
• Isenia
• Isotic Tobryne
• Marunol
• Nebra
• Oculotob
• Ocuracin
• Ocusyn
• Oftalbrax
• Okle
• T Mycin
• Tobacin
• Toberan
• Tobra
• Tobra-Day
• Tobra-V
• Tobracin
• Tobragan
• Tobral
• Tobramaxin
• Tobramex
• Tobrased
• Tobrasol
• Tobrastill
• Tobravisc
• Tobre
• Tobrex
• Tobrimin
• Tobrin
• Tocin
• Tomidrop
• Tomracin
• Trazil ofteno

Tobramycin Brand Names in Pakistan: