Comparison of 24-hour intraocular pressure reduction with two dosing regimens of latanoprost and timolol maleate in patients with primary open-angle glaucoma.
OBJECTIVE
To compare the 24-hour diurnal ocular hypotensive efficacy of two dosing regimens of latanoprost, once daily (8 AM or 10 PM), vs timolol maleate, twice daily.


METHODS
We measured six diurnal intraocular pressure curves (6 AM, 10 AM, 2 PM, 6 PM, 10 PM, and 2 AM) in one randomly selected eye of 34 Greek patients newly diagnosed with primary open-angle glaucoma. The first diurnal curve was an untreated baseline. Patients began taking timolol 0.5%, twice daily, for 2 months. Patients were randomly assigned to latanoprost 0.005% given at 8 AM or 10 PM for 1 month and then changed to the other dosing regimen for 1 month. A diurnal curve was performed after each dosing period.


RESULTS
The baseline diurnal pressure for all 34 subjects was 23.1 +/- 3.7 mm Hg. The average intraocular pressures at 6 AM for patients who were given latanoprost in the evening (17.9 +/- 2.9 mm Hg) was statistically lower than that in patients given timolol solution (20.1 +/- 2.5 mm Hg, P = .003); however, patients who were given timolol demonstrated a similar diurnal intraocular pressure (19.1 +/- 2.8 mm Hg) to both morning (18.8 +/- 3.7 mm Hg) and evening doses (18.8 +/- 3.6 mm Hg) of latanoprost (P =.329). When the two latanoprost dosages were compared directly, evening administration provided a statistically lower intraocular pressure at 10 AM (P = .0001) and morning administration at 10 PM (P = .0001). This study had an 80% power to exclude a 1.2-mm Hg difference between groups.


CONCLUSIONS
This study indicates that in a small population, both latanoprost and timolol are effective in lowering intraocular pressure throughout a 24-hour period; however, latanoprost is most effective in the 12-hour to 24-hour period after administration.
Konstas
A G
AG
University Department of Ophthalmology, AHEPA Hospital, Thessaloniki, Greece.
Maltezos
A C
AC
Gandi
S
S
Hudgins
A C
AC
Stewart
W C
WC
D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage* / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D002940:Circadian Rhythm / Q000187:drug effects*; D004334:Drug Administration Schedule; D005260:Female; D005902:Glaucoma, Open-Angle / Q000188:drug therapy*; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects*; D000077338:Latanoprost; D008297:Male; D008875:Middle Aged; D009883:Ophthalmic Solutions / Q000008:administration & dosage / Q000627:therapeutic use; D011461:Prostaglandins F, Synthetic / Q000008:administration & dosage* / Q000627:therapeutic use; D013999:Timolol / Q000008:administration & dosage* / Q000627:therapeutic use; D014065:Tonometry, Ocular
D000319:Adrenergic beta-Antagonists; D009883:Ophthalmic Solutions; D011461:Prostaglandins F, Synthetic; D000077338:Latanoprost; D013999:Timolol