Effective pupil dilatation with a mixture of 0.75% tropicamide and 2.5% phenylephrine: A randomized controlled trial

• Main Authors: Trinavarat Adisak, Pituksung Auengporn
• Format: Article
• Language: English
• Published: Wolters Kluwer Medknow Publications 2009-01-01
• Series: Indian Journal of Ophthalmology
• Subjects: Mydriatric; phenylephrine; pupil dilatation; tropicamide
• Online Access: http://www.ijo.in/article.asp?issn=0301-4738;year=2009;volume=57;issue=5;spage=351;epage=354;aulast=Trinavarat
• ISSN: 0301-4738; 1998-3689

<b>Purpose:</b> To compare the efficacy in pupil dilatation between a mixture containing 0.75&#x0025; tropicamide and 2.5&#x0025; phenylephrine and the alternate application of 1&#x0025; tropicamide and 10&#x0025; phenylephrine eye drops. <b> Material and Methods</b> : Patients requiring pupil dilatation were randomized to receive one drop of the mixture every 10 min for four times or our standard application of one drop of 1&#x0025; tropicamide alternating with one drop of 10&#x0025; phenylephrine every 10 min for two cycles. Pupil size was measured under bright light with the pupil gauge before, and every 5 min after initial application for 40 min. Application of the drops was discontinued once the pupil diameter reached 7 mm. Blood pressure and pulse rate were monitored every 15 min. <b> Results:</b> Of 40 patients (age 57.3&#x00B1;10.9 years, range 35-70 years), 22 were randomized into the mixture group and 18 into the alternate drug group. Baseline pupil sizes were 1.7&#x00B1;0.5 mm in the mixture group and 1.8&#x00B1;0.4 mm in the alternate drug group. The pupils were successfully dilated to 7 mm within 40 min in 17 patients of the mixture group compared to seven patients in the alternate drug group (<i> P</i> =0.004, Log Rank test). The mean pupil sizes at 40 min were 6.6&#x00B1;0.8 and 6.0&#x00B1;0.9 mm in the mixture and alternate drug groups respectively (<i> P</i> =0.050, t-test). Blood pressure and pulse rate were stable and similar in both groups. <b>Conclusions:</b> The mixture of 0.75&#x0025; tropicamide and 2.5&#x0025; phenylephrine is superior to our standard application of 1&#x0025; tropicamide alternating with 10&#x0025; phenylephrine. It provides faster and more successful pupil dilatation within 40 min.