Purpose:
To report the preliminary results of a case control study todetermine what effect tamulosin has on physiological pupil parameters.
Methods:
16 patients already taking tamulosin were recruited from a urologyclinic. They were compared to 16 healthy controls who had nevertaken tamulosin. Pupil evaluation was by infra-red pupillographictechniques. Pupil diameters in the light and dark, and thenat 15, 30, 60 and 120 minutes after instillation of 10µlof 10% phenylephrine or 10µl of 10% phenylephrine and10µl of 1% cyclopentolate. The two different preparationswere randomised to each eye. The time for 75% recovery of thepupil size following presentation of a standard light stimulus(T3/4) was calculated.
Results:
The cohort on tamulosinhad longer T3/4 times, but dilated less in response phenylephrine(due to the alpha-adrenoceptor antagonist effect of tamulosin)as the healthy controls. We then compared the individual T3/4in this cohort to the normal database collected by the Nationalhospital for Neurology and Neurosurgery to see if all the patientson tamulosin had abnormal T3/4 times.Tamulosin cohort (sub-groupanalysis)
Conclusions:
50% of patients who were on tamulosin had abnormal T3/4 times.These patients had also been on tamulosin for longer indicatingthat the effect of tamulosin on pupillary reactions seems tobe related to duration of use. The patients on tamulosin withnormal T3/4 were similar to the healthy controls. Further workis underway to see if abnormal T3/4 is correlated to the diagnosisof IFIS.
Keywords: pupillary reflex • drug toxicity/drug effects