Q: Ive heard reports that drugs for treating an elarged prostate can cause complications during cataract surgery. What is the latest information on this problem?
A: Flomax (tamsulosin, Boehringer Ingelheim), the most commonly prescribed alpha-1 blocker for benign prostatic hyperplasia (BPH), relaxes smooth muscles in the bladder neck and pros- tate, resulting in an improvement in urine flow. But, the drug may have a similar yet undesirable effect on the iris. Specifically, Flomax has been linked to intraoperative floppy iris syndrome (IFIS).1
Thus, the FDA recently added this precaution to the labelling of the drug: IFIS is a variant of small pupil syndrome and is characterized by the combination of a flaccid iris that billows in response to intraoperative irrigation currents, progressive intraoperative miosis despite preoperative dilation with standard mydriatic drugs, and potential prolapse of the iris toward the phacoemulsification incisions.2
In the study that first identified IFIS, two ophthalmologists, David F. Chang, M.D., and John R. Campbell, M.D., found that IFIS occurred in more than 2% of all cataract patients.1 In Dr. Changs masked prospective study of 900 consecutive eyes, 15 out of 16 patients who had IFIS had taken Flomax.
The problem is that the iris unexpectedly prolapses to otherwise well-constructed incisions, says Dr. Chang, clinical professor at the University of California, San Francisco. This is followed by dramatic pupillary constriction, with a very high incidence of posterior capsule rupture.
|IFIS shows billowing and prolapse of iris, and intraoperative pupil constriction.|
Photo courtesy: David F. Chang, M.D.
A: The first step in avoiding this misadventure is to determine which patients are at risk. The primary-care O.D. is perfectly positioned to help prevent this problem by obtaining a complete medical history and thorough list of the patients medications, says optometrist Howell Findley, clinic director of Commonwealth Eye Surgery, in Lexington, Ky. Be sure to pass this information along to the surgeons office.
IFIS has also been associated with other alpha blockers, such as Hytrin (terazosin, Abbott), Cardura (doxazosin, Pfizer) and Uroxatral (alfuzosin, Sanofi-Synthelabo), says Dr. Chang. It is important now to inquire about these drugsespecially in any cataract patient who has a poorly dilating pupil.
Men are not the only ones who can develop IFIS. Urologists sometimes prescribe tamsulosin off-label for urinary retention in women.3
Discontinuing the drug generally will not prevent IFIS, as the drug appears to maintain a lasting effect. IFIS appears to be a semi-permanent loss of iris dilator muscle tone, explained Dr. Chang. We have many documented cases in patients who have been off the drug for more than two years.
Pharmacologic methods to prevent IFIS during surgery are not consistently effective, Dr. Chang says. For most cases, he advocates that surgeons use iris retractors, a pupil expansion ring or a viscoadaptive agent (specifically Healon5 [sodium hyaluranate 2.3%, AMO]) to maintain pupil dilationbut all of these require more surgical time.
The bottom line for the comanaging O.D.: Notify the surgeon of any IFIS suspect. This allows the surgeons office to schedule adequate operating room time for the patient, Dr. Findley says. It also alerts the surgical team that the pupil may not dilate normally and that the patient has a higher risk for intraoperative complications.
1. Chang DF, Campbell JR. Intraoperative floppy iris syndrome associated with tamsulosin. J Cataract Refract Surg 2005 Apr;31(4):664-73.
2. Boehringer Ingelheim. Flomax prescribing information. www.bidocs.com/renetnt:/Prescribing+Information/PIs/Flomax+Caps/Flomax.pdf. Accessed 16 November 2005
3. Reitz A, Haferkamp A, Kyburz T, et al. The effect of tamsulosin on the resting tone and the contractile behaviour of the female urethra: a functional urodynamic study in healthy women. Eur Urol 2004 Aug;46(2):235-40.