Year : 1985 | Volume
: 33 | Issue : 4 | Page : 225--227
Effect of timolol on intra-ocular pressure in the presence of systemic propranolol in healthy subjects
RN Sud, Anil Kumar Kataria
Dayanand Medical College & Hospital, Ludhiana, India
R N Sud
96-B, Kitchlu Nagar, Ludhiana-141001
|How to cite this article:|
Sud R N, Kataria AK. Effect of timolol on intra-ocular pressure in the presence of systemic propranolol in healthy subjects.Indian J Ophthalmol 1985;33:225-227
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Sud R N, Kataria AK. Effect of timolol on intra-ocular pressure in the presence of systemic propranolol in healthy subjects. Indian J Ophthalmol [serial online] 1985 [cited 2021 Sep 22 ];33:225-227
Available from: https://www.ijo.in/text.asp?1985/33/4/225/30796
The topical use of timolol maleate, betaadrenergic blocking agent, in the treatment of chronic simple glaucoma is now well known. A number of systemic beta blockers produce a fall in intra-ocular pressure in normal persons and in patients with increased intra-ocular pressure. Recent reports suggest that systemic administration of the beta blocker, propranolol in high doses inhibits the effects of topical timolol, while low doses of systemic propranolol do not have any inhibitory effect on the action of topical timolol. The present study was undertaken to find out whether the effect of timolol (a beta blocker) used topically, was modified by the systemic administration of another beta blocker-propranolol.
MATERIALS AND METHODS
The present study was undertaken on seventy five healthy persons of Indian origin, with normal eyes. These were divided into three groups A,B & C, of 25 each. In group A, each subject was given 80 mg. of propranolol orally for three days. Subjects in group B received 160 mg. of propranolol orally whereas the subjects of group C were not given any medication systemically which could affect intra-ocular pressure. Patients with known contra-indication to betaadrenergic blocking drugs and those receiving medication for systemic effect that might alter intra-ocular pressure were not included.
In each group on 4th day, the intra-ocular tension was recorded with Schiotz tonometer in recumbent position. At the start of procedure, one drop of timolol maleate (0.5%) was instilled in the right eye of all the patients in three groups, whereas a placebo was used in the left eye of each person in group A,B and C. Pulse, blood pressure and respiration rate were noted in the begin ning of procedure. Intra-ocular tension was recorded 1 hourly for the next five hours starting two hours after instillation of eye drops. Pulse, blood pressure and respiration rate were again noted at the end of procedure and one drop of antibiotic eye drops was instilled in both eyes of each patient. All the readings obtained as mentioned above were noted. Any side effect during the procedure, local or systemic, was noted.
In group A, 18 subjects (72%) showed a fall in intra-ocular tension by more than 6 mm Hg, whereas 5 subjects (20%) recorded a fall of 4-6 mm Hg and 2 subjects (8%) showed a fall of 3 or less than 3 mm Hg [Table 1]. The fall was statistically significant upto 1 %.
In group B, the same procedure was adopted as in group A, except that the dose of propranolol was increased to 160 mg per day orally. In this group, 18 persons (72%) had a fall in intra-ocular tension from 0-3 mm Hg whereas the remaining 7 cases (28%) had a fall in intra-ocular tension ranging from 4-6 mm Hg and none of the cases showed a fall in intra-ocular tension of more than 6 mm Hg [Table 2]. The fall was statistically significant upto 1%.
In group C, 17 subjects (68%) had a fall in intra-ocular tension of more than 6 mm Hg whereas 6 cases (24%) showed a fall ranging between 4-6 mm Hg and 2 cases (8%) a fall of 0-3 mm Hg [Table 3]. The fall was statistically significant upto 1%.
In our study maximum fall recorded was 10.4 mm Hg and the minimum fall recorded was 1,7 mm Hg. In group A, 92% of the subjects showed good response to Timolol eye drops and in group C, 92% of the subjects responded well to topical timolol, in which no propranolol was given and the average fall in intra-ocular pressure of 5.5 mm Hg was noted after instillation of one drop of timolol maleate. The fall in group A and C was statistically significant (upto 1%) and equal in both the groups. This observation is similar to that of Blondeau et a1 who observed after timolol eye drops a substantial fall in intra-ocular pressure in persons who had taken a placebo and those who had taken the lower dose of propranolol by an almost identical extent.
In group B, after instillation of timolol maleate overall average fall of 2.2 mm Hg was recorded in the present study, while the study conducted by Blondeau et al showed an average fall of 1.0 mm Hg. Group B showed less or no effect of timolol eye drops in 72°x, of the subjects and 28% of the cases showed some lowering of intra-ocular tension whereas in Group A and Group C, 92% of the cases showed good response to timolol eye drops and 8 % of the cases in each group showed less response, but there was no difference statistically in any of the groups (upto 1 %). This indicates that large doses of systemic propranolol did not have a significant effect on the action of topical Timolol. This is in contrast to the findings of Blondeau et al who found that large doses of propranolol reduced the effect of topical timolol. In our study, there was no statistically significant difference in the effect of topical timolol, with or without systemic propranolol, low or high doses.
In the present study on 75 subjects, the effect of 0.5% timolol eye drops on intraocular tension was assessed in the presence of varying doses of oral propranolol. These subjects were divided into three groups A,B & C of 25 each. The following conclusions were made :-
The topical use of timolol eye drops has an excellent effect in lowering the intraocular tension even when propranolol is used systemically.Even high doses of systemic propranolol have no inhibitory effect on local use of timoloi eye drops.No local or systemic side effect was observed.
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