External ocular toxicity of dipivalyl epinephrine

Of 26 patients enrolled in a study designed to assess the usefulness of dipivalyl epinephrine 0.1%, administered topically at 12-hour intervals, for lowering intraocular pressure in patients with glaucoma and ocular hypertension, six patients (23.1%) developed adverse external ocular side effects severe enough to require that the drug be discontinued. Four of these six patients had a history of previous intolerance to epinephrine. The other two had successfully used epinephrine HCl 2% for more than two years before being treated with dipivalyl epinephrine and developed an adverse reaction after taking the drug 18 and 22 months, respectively. One patient with a history of epinephrine intolerance has successfully used dipivalyl epinephrine for 26 months to date. Our observations suggest that duration of exposure is an important factor in the development of sensitization to topically applied dipivalyl epinephrine.