Dorzolamide

Potential additive effect of oral carbonic anhydrase inhibitor with dorzolamide hydrochloride ophthalmic solution. () Potential acid-base and electrolyte disturbances. ( 7.2 )

7.1 Oral Carbonic Anhydrase Inhibitors There is a potential for an additive effect on the known systemic effects of carbonic anhydrase inhibition in patients receiving an oral carbonic anhydrase inhibitor and dorzolamide hydrochloride ophthalmic solution. The concomitant administration of dorzolamide hydrochloride ophthalmic solution and oral carbonic anhydrase inhibitors is not recommended.

7.2 High-Dose Salicylate Therapy Although acid-base and electrolyte disturbances were not reported in the clinical trials with dorzolamide hydrochloride ophthalmic solution, these disturbances have been reported with oral carbonic anhydrase inhibitors and have, in some instances, resulted in drug interactions (e.g., toxicity associated with high-dose salicylate therapy). Therefore, the potential for such drug interactions should be considered in patients receiving dorzolamide hydrochloride ophthalmic solution.

8.1 Pregnancy Risk Summary There are no adequate and well-controlled studies in pregnant women with dorzolamide hydrochloride ophthalmic solution. Dorzolamide caused fetal vertebral malformations when administered orally to rabbits at 2.5 mg/kg/day (37 times the clinical exposure). Dorzolamide administered during the period of organogenesis was not teratogenic in rabbits dosed up to 1 mg/kg/day (15 times the clinical exposure). Dorzolamide hydrochloride administered orally to rats during late gestation and lactation caused growth delays in offspring at 7.5 mg/kg/day (52 times the clinical exposure). Growth was not delayed at 1 mg/kg/day (8.0 times the clinical exposure).

The background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively. Data Animal Data Developmental toxicity studies were conducted in pregnant rabbits administered dorzolamide hydrochloride orally during the period of organogenesis from gestation days 6 through 18 at doses of 0.2, 1, 2.5, 5, and 10 mg/kg/day. The developmental lowest observed adverse effect level (LOAEL) was 2.5 mg/kg/day, based on vertebral malformations and decreased fetal body weight.

The maternal LOAEL was 2.5 mg/kg/day, based on metabolic acidosis and reduced weight gain. The maternal and developmental no adverse effect levels (NOAELs) were 1 mg/kg/day. The rabbit doses of 1 and 2.5 mg/kg/day represent estimated plasma C max levels in rabbits 15 and 37 times higher than the lower limit of detection in human plasma following ocular administration, respectively. Dorzolamide hydrochloride was administered orally to rats during late gestation and lactation (gestation day 17 through postpartum day 20) at doses of 0.1, 1, or 7.5 mg/kg/day.

The developmental LOAEL was 7.5 mg/kg/day, based on reduced birth weight, reduced weight gain, and a slight delay in postnatal development (incisor eruption, vaginal canalization and eye openings) secondary to lower offspring body weight. This 7.5 mg/kg/day dose represents an estimated plasma C max level in rats 52 times higher than the lower limit of detection in human plasma following ocular administration. The developmental NOAEL was 1 mg/kg/day. The maternal LOAEL was 1 mg/kg/day, based on reduced body weight gain. The maternal NOAEL was 0.1 mg/kg/day. The rat doses of 1 and 0.1 mg/kg/day represent estimated plasma C max levels in rats approximately 8.0 times and…