Interspecies scaling considerations predict that the doses selected of Alprenoxime (1 and 5 mg/kg) are pharmacologically comparable or greater than doses used in rodent studies (2 and 6 mg/kg). More importantly, the prolonged ocular antihypertensive effects that are shown with 1% ophthalmic solutions indicate that the i.v. dose tested in the present study is likely to be more than two orders of magnitude greater than probable therapeutic doses.