title: The differential pupillary response to 2.5% phenylephrine in patients taking tamsulosin.
abstract: OBJECTIVE
  To determine if a pharmacological test could be developed to determine iris dilator dysfunction in patients taking tamsulosin.
  
  
  METHODS
  Patients taking tamsulosin and controls were recruited from the Urology and Ophthalmology clinics at the Montefiore Medical Center. The patient's right eye (OD) was dilated with phenylephrine hydrochloride 2.5% and tropicamide 1%. The patient's left eye (OS) was dilated with tropicamide 1% alone. Forty minutes after dilation, pupillary diameter was measured in both eyes.
  
  
  RESULTS
  Thirty-eight tamsulosin subjects and 43 controls met the inclusion criteria for the study. The tamsulosin-treated patients dilated less with phenylephrine than controls (0.61±0.4 vs. 1.10±0.45 mm, respectively P<0.001). Receiver operating characteristic curves comparing maximal pupillary dilation versus differential pupillary dilation in tamsulosin patients relative to controls shows a greater area under the curve for differential dilation (0.8 vs. 0.6, respectively). A correlation between smooth muscle dysfunction and length of time on tamsulosin was observed. Patients using tamsulosin for <1 month had an average OD-OS difference of 0.85±0.5 mm. Patients who were on tamsulosin for >1 month had an average OD-OS difference of 0.52±0.32 mm (P<0.01, Mann-Whitney).
  
  
  CONCLUSIONS
  Patients treated with tamsulosin demonstrated a significantly decreased iris dilatory response to the selective adrenergic effects of phenylephrine compared to controls. Additionally, it appears that longer duration of exposure to tamsulosin increases the likelihood of dilator dysfunction.
authors: Montefiore Medical Center, The Henkind Eye Institute , Bronx, New York.
authors: Joel H
authors: JH
authors: Hillelsohn
authors: Grace T
authors: GT
authors: Liu
authors: Maggie B
authors: MB
authors: Hymowitz
authors: Anurag
authors: A
authors: Shrivastava
authors: Jeffrey S
authors: JS
authors: Schultz
mesh_terms: D058646:Adrenergic alpha-1 Receptor Agonists / Q000008:administration & dosage* / Q000494:pharmacology; D058668:Adrenergic alpha-1 Receptor Antagonists / Q000008:administration & dosage* / Q000009:adverse effects / Q000494:pharmacology; D000368:Aged; D016022:Case-Control Studies; D004347:Drug Interactions; D006801:Humans; D007431:Intraoperative Complications / Q000139:chemically induced / Q000188:drug therapy; D007499:Iris Diseases / Q000139:chemically induced / Q000175:diagnosis* / Q000188:drug therapy; D008875:Middle Aged; D010656:Phenylephrine / Q000008:administration & dosage* / Q000494:pharmacology; D011446:Prospective Studies; D011680:Pupil / Q000187:drug effects*; D012372:ROC Curve; D013449:Sulfonamides / Q000008:administration & dosage* / Q000009:adverse effects / Q000494:pharmacology; D000077409:Tamsulosin; D014331:Tropicamide / Q000008:administration & dosage / Q000494:pharmacology
chemical_list: D058646:Adrenergic alpha-1 Receptor Agonists; D058668:Adrenergic alpha-1 Receptor Antagonists; D013449:Sulfonamides; D010656:Phenylephrine; D000077409:Tamsulosin; D014331:Tropicamide