Corticoids suppress the inflammatory response to a variety of agents and they probably delay or slow
healing. Since corticoids may inhibit the body's defense mechanism against infection, a concomitant
antimicrobial drug may be used when this inhibition is considered to be clinically significant.
Dexamethasone is a potent corticoid.
The antibiotic component in the combination (tobramycin) is included to provide action against
susceptible organisms. In vitro studies have demonstrated that tobramycin is active against susceptible
strains of the following microorganisms:
Staphylococci, including S. aureus and S. epidermidis (coagulase-positive and coagulase-negative),
including penicillin-resistant strains.
Streptococci, including some of the Group A-beta-hemolytic species, some nonhemolytic species, and
some Streptococcus pneumoniae.
Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Enterobacter aerogenes, Proteus
mirabilis, Morganella morganii, most Proteus vulgaris strains, Haemophilus influenzae and H. aegyptius,
Moraxella lacunata, Acinetobacter calcoaceticus and some Neisseria species.
Bacterial susceptibility studies demonstrate that in some cases microorganisms resistant to gentamicin
remain susceptible to tobramycin.
No data are available on the extent of systemic absorption from TOBRADEX® (tobramycin and
dexamethasone ophthalmic suspension); however, it is known that some systemic absorption can occur
with ocularly applied drugs. If the maximum dose of TOBRADEX® (tobramycin and dexamethasone
ophthalmic suspension) is given for the first 48 hours (two drops in each eye every 2 hours) and
complete systemic absorption occurs, which is highly unlikely, the daily dose of dexamethasone would
be 2.4 mg. The usual physiologic replacement dose is 0.75 mg daily. If TOBRADEX® (tobramycin and
dexamethasone ophthalmic suspension) is given after the first 48 hours as two drops in each eye every
4 hours, the administered dose of dexamethasone would be 1.2 mg daily.