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dc.contributor.authorKiilgaard, J F
dc.contributor.authorPedersen, D B
dc.contributor.authorEysteinsson, T
dc.contributor.authorla Cour, M
dc.contributor.authorBang, K
dc.contributor.authorJensen, P K
dc.contributor.authorStefansson, E
dc.date.accessioned2009-09-29T10:00:22Z
dc.date.available2009-09-29T10:00:22Z
dc.date.issued2004-02-01
dc.date.submitted2009-09-28
dc.identifier.citationBr J Ophthalmol. 2004, 88(2):276-9en
dc.identifier.issn0007-1161
dc.identifier.pmid14736791
dc.identifier.doi10.1136/bjo.2003.021857
dc.identifier.urihttp://hdl.handle.net/2336/82913
dc.descriptionTo access publisher full text version of this article. Please click on the hyperlink in Additional Links fielden
dc.description.abstractBACKGROUND/AIMS: The authors have previously reported that carbonic anhydrase inhibitors such as acetazolamide and dorzolamide raise optic nerve oxygen tension (ONPO(2)) in pigs. The purpose of the present study was to investigate whether timolol, which belongs to another group of glaucoma drugs called beta blockers, has a similar effect. In addition, the effect of dorzolamide and timolol in combination was studied. METHODS: Polarographic oxygen electrodes were placed transvitreally over the optic disc in anaesthetised pigs and ONPO(2) was recorded continually. Drugs were administered intravenously either as 100 mg timolol followed by 500 mg dorzolamide (n = 5), 500 mg dorzolamide followed by 100 mg timolol (n = 5), or 100 mg timolol and 500 mg dorzolamide given simultaneously (n = 5). Arterial blood pressure, blood gasses, and heart rate were recorded. RESULTS: ONPO(2) was unaffected by administration of 100 mg timolol as an intravenous injection (n = 5). Administration of 500 mg dorzolamide by itself significantly increased ONPO(2) from 2.96 (SD 0.62) kPa to 3.69 (SD 0.88) kPa (n = 4, p = 0.035). The dorzolamide induced ONPO(2) increase was not significantly different from the ONPO(2) increases were seen when dorzolamide was administered simultaneous with (n = 5) or 35 minutes (n = 5) after 100 mg timolol. CONCLUSION: Systemic administration of timolol does not affect the optic nerve oxygen tension despite its lowering effect on the intraocular pressure. Additionally, timolol does not affect the ONPO(2) increasing effect of dorzolamide.
dc.language.isoenen
dc.publisherBritish Medical Associationen
dc.relation.urlhttp://dx.doi.org/10.1136/bjo.2003.021857en
dc.subject.meshAdrenergic beta-Antagonistsen
dc.subject.meshAnimalsen
dc.subject.meshAntihypertensive Agentsen
dc.subject.meshBlood Pressureen
dc.subject.meshCarbon Dioxideen
dc.subject.meshCarbonic Anhydrase Inhibitorsen
dc.subject.meshDrug Interactionsen
dc.subject.meshHeart Rateen
dc.subject.meshIntraocular Pressureen
dc.subject.meshOptic Disken
dc.subject.meshOxygenen
dc.subject.meshPartial Pressureen
dc.subject.meshSulfonamidesen
dc.subject.meshSwineen
dc.subject.meshThiophenesen
dc.subject.meshTimololen
dc.titleOptic nerve oxygen tension: the effects of timolol and dorzolamide.en
dc.typeArticleen
dc.contributor.departmentDepartment of Ophthalmology, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen Ø, Denmark. jfk@dadlnet.dken
dc.identifier.journalBritish journal of ophthalmologyen
html.description.abstractBACKGROUND/AIMS: The authors have previously reported that carbonic anhydrase inhibitors such as acetazolamide and dorzolamide raise optic nerve oxygen tension (ONPO(2)) in pigs. The purpose of the present study was to investigate whether timolol, which belongs to another group of glaucoma drugs called beta blockers, has a similar effect. In addition, the effect of dorzolamide and timolol in combination was studied. METHODS: Polarographic oxygen electrodes were placed transvitreally over the optic disc in anaesthetised pigs and ONPO(2) was recorded continually. Drugs were administered intravenously either as 100 mg timolol followed by 500 mg dorzolamide (n = 5), 500 mg dorzolamide followed by 100 mg timolol (n = 5), or 100 mg timolol and 500 mg dorzolamide given simultaneously (n = 5). Arterial blood pressure, blood gasses, and heart rate were recorded. RESULTS: ONPO(2) was unaffected by administration of 100 mg timolol as an intravenous injection (n = 5). Administration of 500 mg dorzolamide by itself significantly increased ONPO(2) from 2.96 (SD 0.62) kPa to 3.69 (SD 0.88) kPa (n = 4, p = 0.035). The dorzolamide induced ONPO(2) increase was not significantly different from the ONPO(2) increases were seen when dorzolamide was administered simultaneous with (n = 5) or 35 minutes (n = 5) after 100 mg timolol. CONCLUSION: Systemic administration of timolol does not affect the optic nerve oxygen tension despite its lowering effect on the intraocular pressure. Additionally, timolol does not affect the ONPO(2) increasing effect of dorzolamide.


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