Tamsulosin Use Linked to Serious Ophthalmic Adverse Events After Cataract Surgery

Laurie Barclay, MD

May 19, 2009

May 19, 2009 — Tamsulosin use within 14 days of cataract surgery was significantly associated with serious postoperative ophthalmic adverse events, according to the results of a nested case-control analysis of a population-based retrospective cohort study reported in the May 20 issue of the Journal of the American Medical Association.

"Both benign prostatic hyperplasia (BPH) and cataract formation are common in older men," write Chaim M. Bell, MD, PhD, from the University of Toronto in Toronto, Ontario, Canada, and colleagues. "The alpha-adrenergic receptor blocker tamsulosin is frequently prescribed to treat BPH, and research suggests this drug may increase the intraoperative difficulty of cataract surgery. No studies have documented whether use of tamsulosin or other alpha-blocker drug therapies affect the risk of serious postoperative adverse events."

Using linked healthcare databases from Ontario, Canada, the investigators identified and included all men 66 years or older who had cataract surgery between 2002 and 2007 (n = 96,128). The primary endpoint of the study was a composite of procedures needed for retinal detachment, lost lens or lens fragment, or endophthalmitis that were performed within 14 days after cataract surgery.

This endpoint was compared in men who received tamsulosin or other alpha-blockers in the year before cataract surgery vs men not treated with these medications during that time. Recent drug exposure (within 14 days before surgery) or previous drug exposure (15 - 365 days before surgery) was analyzed separately.

In the study cohort, 3550 patients (3.7%) had recent exposure to tamsulosin and 7426 patients (7.7%) had recent exposure to other alpha-blockers. An adverse event was reported in 284 patients (0.3%), including 100 with suspected endophthalmitis, 175 who had a procedure for lost lens or lens fragment, 35 for retinal detachment, and 26 for both. The investigators compared 280 of these cases vs 1102 randomly selected control subjects matched for age, surgeon, and year of surgery.

Patients with recent tamsulosin exposure had significantly more frequent adverse events (7.5% vs 2.7%; adjusted odds ratio [OR], 2.33; 95% confidence interval [CI], 1.22 - 4.43). However, adverse events were not associated with recent exposure to other alpha-blockers (7.5% vs 8.0%; adjusted OR, 0.91; 95% CI, 0.54 - 1.54) or with previous exposure to tamsulosin (≤ 1.8% vs 1%; adjusted OR, 0.94; 95% CI, 0.27 - 3.34) or to other alpha-blockers (2.9% vs 2.1%; adjusted OR, 1.08; 95% CI, 0.47 - 2.48). The estimated number needed to harm with recent tamsulosin treatment was 255 (95% CI, 99 - 1666).

"Exposure to tamsulosin within 14 days of cataract surgery was significantly associated with serious postoperative ophthalmic adverse events," the study authors write. "There were no significant associations with exposure to other alpha-blocker medications used to treat BPH."

Limitations of this study include use of administrative health data; inability to determine whether prescribed drugs were actually consumed; small numbers in patient subgroups, limiting statistical power; possible underestimate of adverse event rates; and possible surveillance and ascertainment bias.

"Because the combination of cataract surgery and tamsulosin exposure is relatively common, patients should be properly appraised [sic] of the risks of drug therapy and preoperative systems should focus on the identification of tamsulosin use by patients," the study authors conclude. "In this way, surgeons can plan and prepare for a potentially more complicated procedure or refer to someone with more experience."

In an accompanying editorial, Alan H. Friedman, MD, from the Mount Sinai School of Medicine in New York, NY, notes that discontinuation of tamsulosin may not reliably reduce the severity of intraoperative floppy iris syndrome (IFIS).

"To mitigate the potential intraoperative problems, several pharmacological and mechanical strategies have been proposed: preoperative dilation with strong cycloplegic agents such as atropine or homatropine intraoperative use and highly viscous agents, low flow of fluids into and out of the eye, iris retractors, and mechanical pupillary expansion rings," Dr. Friedman writes.

"Although the prescribing information for tamsulosin includes IFIS as a 'general precaution,' the data on the risk of this complication should be reassessed to determine whether a 'black box' warning should be issued to caution the ophthalmic surgeon and the general public (men in particular) of danger to the eye of taking alpha1-adrenergic blocking agents before cataract surgery."

The Canadian Institutes of Health Research (CIHR) Institute of Nutrition, Metabolism, and Diabetes, the CIHR Institute of Gender and Health, and the CIHR Institute of Aging supported this study. This study was conducted at the Institute for Clinical Evaluative Sciences, which is funded by an annual grant from the Ontario Ministry of Health and Long-Term Care. Dr. Bell is supported by a New Investigator Award from the CIHR Institute of Aging. Two of the study authors have disclosed various financial relationships with Alcon, Novartis, and/or Bayer Inc.

Dr. Friedman has disclosed no relevant financial relationships.

JAMA. 2009;301:1991-1996, 2044-2045.

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