Indian Journal of Ophthalmology

ARTICLES
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

Correspondence Address:
R N Sud
96-B, Kitchlu Nagar, Ludhiana-141001
India




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


How to cite this URL:
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


Full Text

The topical use of timolol maleate, beta­adrenergic blocking agent, in the treatment of chronic simple glaucoma is now well ­known[1]. A number of systemic beta blockers produce a fall in intra-ocular pressure in normal persons and in patients with increased intra-ocular pressure[2]. 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[3]. 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.

 OBSERVATIONS



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%.

 DISCUSSION



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[3] 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[3] 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[3] 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.

 SUMMARY



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.

References

1Boger, W.P., III, Puliafito, CA , Steinert R.F., and Langston, D.P., 1978, Ophthalmology, 85: 257.
2Tutton, M.K., and Smith R.J.H. 1983, Brit. J Ophthalmol. 67: 664.
3Blondecu, P., Cote, M. and Tetrault, L. 1983, Can. J. Ophthalmol 18: 18.