Titre du document / Document title

The lack of efficacy of topical beta-blockers, timolol and betaxolol on intraocular pressure in nigerian healthy volunteers

Auteur(s) / Author(s)

OLATEJU S. O. ⁽¹⁾ ; AJAYI A. A. ⁽²⁾ ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

⁽¹⁾ Department of Surgery (Ophthalmology Unit) Obafemi Awolowo University, Ile-lfe, NIGERIA
⁽²⁾ Department of Medicine Obafemi Awolowo University, Ile-Ife, NIGERIA

Résumé / Abstract

Purpose The beta-adrenoceptor antagonists are commonly used drugs in ophthalmic and medical practice. While beta-blockers may show reduced antihypertensive efficacy in African patients, the effect of beta-blockers on intraocular pressure (IOP) in African healthy volunteers is less well known. Methods This single-masked, placebo-controlled, randomised study was conducted to investigate the response of healthy Nigerian volunteers to a single drop of the beta-adrenoceptor antagonists timolol and betaxolol. Twenty-five volunteers participated in the study; however, only 19 were able to complete the study. The concentrations of the beta-blocker used were 0.0625%, 0.125%, 0.25% and 0.5%. One eye of the volunteers was used while the other eye served as control. The baseline IOP was documented and IOP measured hourly over 6 h. Pupillary size, corneal sensitivity and visual acuity were also assessed. Cardiovascular parameters were also documented hourly (blood pressure, heart rate, pulse rate). Results Only 0.5% concentrations of both beta-adrenoceptor antagonists caused any significant IOP reduction in normal volunteers (p < 0.05). The maximal falls were -2.33 ± 2.2 mmHg and -1.23 ± 0.6 mmHg with timolol and betaxolol, respectively. The IOP reduction produced lasted for only 4 h, after which the IOP returned to baseline. There was also an overshoot of the IOP above the baseline values in all the volunteers (+2.0 to +2.3 mmHg). There was no significant change in the cardiovascular parameters. There was no effect on the pupillary size, visual acuity or corneal sensitivity. There was no significant change in IOP and cardiovascular parameters in the placebo group. Conclusions Both beta-adrenoceptor antagonists caused an attenuated IOP reduction in African normal volunteers, compared with values reported in Caucasians. There was a rebound intraocular hypertensive effect demonstrated with both beta-adrenergic antagonists in blacks.

Revue / Journal Title

Eye   ISSN 0950-222X   CODEN EYEEEC 

Source / Source

1999, vol. 13 (6), pp. 758-763 (14 ref.)

Langue / Language

Anglais

Editeur / Publisher

Nature Publishing Group, Basingstoke, ROYAUME-UNI  (1987) (Revue)

Mots-clés anglais / English Keywords

Timolol ; Antagonist ; β-Adrenergic receptor ; Betaxolol ; Chemotherapy ; Local administration ; Treatment ; Intraocular pressure ; Human ; Healthy subject ; Nigeria ; Ocular hypertension ; Treatment efficiency ; Africa ; Eye disease ;

Mots-clés français / French Keywords

Timolol ; Antagoniste ; Récepteur β-adrénergique ; Bétaxolol ; Chimiothérapie ; Voie locale ; Traitement ; Tonus oculaire ; Homme ; Individu sain ; Nigéria ; Hypertonie oculaire ; Efficacité traitement ; Afrique ; Oeil pathologie ;

Mots-clés espagnols / Spanish Keywords

Timolol ; Antagonista ; Receptor β-adrenérgico ; Betaxolol ; Quimioterapia ; Vía local ; Tratamiento ; Tono ocular ; Hombre ; Individuo sano ; Nigeria ; Hipertensión ocular ; Eficacia tratamiento ; Africa ; Ojo patología ;

Localisation / Location

INIST-CNRS, Cote INIST : 21076, 35400008150501.0110