Intraoperative Floppy Iris Syndrome Seen With Tamsulosin
Last year, David F. Chang, MD, and John R. Campbell, MD, reported on the incidence of intraoperative floppy iris syndrome (IFIS) in cataract surgery patients.1 Their findings were based on two companion studies they conducted to examine the incidence, characteristics, surgical outcomes and etiology of IFIS (Figures 1 to 3). Using retrospective observations by Dr. Campbell regarding a possible association with tamsulosin (Flomax; Boehringer-Ingelheim Pharmaceutical, Ridgefield, Connecticut), they attempted to evaluate IFIS with both a retrospective and a prospective study.
Tamsulosin is one of several systemic alpha-1 blockers indicated for the treatment of urinary symptoms of benign prostatic hypertrophy. Alpha-1 blockers improve urinary outflow by relaxing the smooth muscle in the prostate and bladder neck. A side effect can include postural hypotension due to alpha-1 blockade of the vascular wall's smooth muscle.2
"[Tamsulosin] does not affect vision health or eye health," said Dr. Chang in an American Academy of Ophthalmology (AAO) news release. "But it blocks the dilator muscle in the iris, and during cataract surgery the eye needs to be dilated." Dr. Chang is clinical professor of ophthalmology at the University of California San Francisco.
STUDY DATA
In a prospective study of 900 consecutive cases, Dr. Chang was masked to the patients' medication history. Approximately 2% of the eyes (21/900) and 2% of the total patients (16/741) were deemed to have a floppy iris. Fifteen of these 16 patients were either taking tamsulosin or had previously taken the agent. According to Dr. Chang, this systemic alpha-1 antagonist is the most commonly prescribed medication for benign prostatic hypertrophy. None of the 725 non-IFIS patients took tamsulosin.
The retrospective study evaluated every cataract surgery performed in a two-surgeon practice during the 2003 calendar year. A floppy iris was noted in the operative report in approximately 2% of the total eyes (16/706) and patients (10/511). All of the IFIS patients were taking tamsulosin. Six patients on tamsulosin therapy did not have a floppy iris noted in the operative report. An additional 1.5% (11/706) of the patients were taking other systemic alpha-blockers (hytrin [Abbott Laboratories, North Chicago, Illinois], cardura [Pfizer, New York] or minipress [Pfizer]). None of these patients demonstrated a floppy iris. The rate of IFIS in the two combined studies — totaling more than 1,600 eyes and 1,250 patients — was 2%.
Reporting in Cataract & Refractive Surgery Today, Dr. Change wrote that the findings convey the importance of ophthalmologists' recognizing and learning how to manage IFIS.2
US FDA ACTION
Following the announcement of Drs. Chang and Campbell's findings, US ophthalmologists were asked to track the incidence of IFIS in cataract patients who were taking tamsulosin and other prostate drugs. They were to send reports of verified cases to the US Food and Drug Administration (FDA). The FDA then responded to physicians' concerns by approving a label change for the drugs that reads, "The patient's ophthalmologist should be prepared for possible modification to their surgical technique."
The AAO notified its members of the FDA label change and recommended that they thoroughly question their male cataract patients about prostate medications before surgery.
In addition to having a pupil that will not dilate properly, patients with IFIS will also have an iris that behaves erratically, and the pupil may suddenly constrict during surgery, increasing the risk of complications.
RESPONSE IN THE UK
Reporting in Eye, Avinash Gurbaxani, MD, and Richard Packard, MD, MD, DO, FRCS, FROphth, described the use of intracameral phenylephrine to prevent IFIS during cataract surgery in patients on tamsulosin.3 They found that it was a simple and effective tool to prevent the effects of IFIS. There was a significant reduction in the iris of mobility and unexpected fluttering. Patients also had sustained papillary dilatation, they wrote.
Dr. Gurbaxani told Cataract & Refractive Surgery Today Europe, that although there has been no formal evaluation of how prevalent IFIS is in Europe, awareness is increasing and more surgeons recognize the condition. Although IFIS is not listed as a side effect of tamsulosin in the British National Formulary, a report about the link was recently published in the British Journal of Urology.4 Dr. Gurbaxani is in the department of ophthalmology, King Edward VII Hospital, Berkshire, UK.
"As we have described a simple yet effective tool for ophthalmic surgeons to use to counter this, we do not think urologists need to stop prescribing this medication. However, surgeons should anticipate this condition when they know their patients are on tamsulosin," Dr. Gurbaxani said.
David F. Chang, MD, is clinical professor at the University of California, San Francisco, and is in private practice in Los Altos, California. Dr. Chang is a consultant for Advanced Medical Optics, Inc., but he has no financial interest in the products mentioned. Dr. Chang may be reached at ceye@earthlink.net or +1 650 948 9123.
Avinash Gurbaxani, MD, is in the department of ophthalmology, King Edward VII Hospital, Berkshire, UK. He may be reached at avigurbaxani@yahoo.co.in or +01753 860 441.
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