Consider Cataracts Before Prescribing Alpha Blockers for Your Patients

If you're about to prescribe an alpha blocker for an older adult with hypertension or a prostate or urinary retention problem, consider whether the patient has cataracts before you prescribe. That's because the use of alpha blockers -- especially tamsulosin, marketed as Flomax -- is associated with an eye condition that makes cataract surgery more difficult, even in patients who no longer use these drugs. So says a July 2 educational update statement (2-page Word file; About Downloading) from the American Society of Cataract and Refractive Surgery, or ASCRS, and the American Academy of Ophthalmology, or AAO.

The two ophthalmology organizations are reaching out to primary care physicians to highlight the association between alpha blockers and a condition called intraoperative floppy iris syndrome, or IFIS, which can complicate cataract surgery.

"When we do cataract surgery, the wider the pupil dilates, the better we see the internal anatomy," says David Chang, M.D., chair of the ASCRS Cataract Clinical Committee and clinical professor of ophthalmology at the University of California, San Francisco. "IFIS causes poor preoperative pupil dilation; billowing and prolapse of the iris, which is floppy instead of rigid; and progressive constriction of the pupil during surgery. Once the pupil constricts intraoperatively, the risk of complications such as tearing the lens capsule or the iris rises significantly.

"The most common way of dealing with poor preoperative pupil dilation used to involve stretching the pupil with instruments -- but because of the floppy iris, pupil stretching backfires with IFIS and makes the situation worse."

Chang and a colleague first reported on IFIS and its association with tamsulosin in 2005. Since then, IFIS has been reported with other alpha blockers, but there appears to be growing evidence that IFIS is either more severe or more common with tamsulosin use, Chang says. The ASCRS-AAO statement says that in one prospective study, 90 percent of 167 eyes in patients taking tamsulosin exhibited some degree of IFIS during cataract surgery.

Tamsulosin is selective for the alpha-1A receptor subtype, which is predominant in the prostate, says Chang; the same alpha-1 subtype also is predominant in the iris.

The ASCRS-AAO statement includes highlights of a 2008 online survey ASCRS conducted to learn about members' clinical experience with IFIS. According to the statement, 95 percent of the nearly 1,000 respondents reported cataract surgery was more difficult in patients who were taking or had taken tamsulosin, and 77 percent said there was increased risk in patients taking tamsulosin compared with patients who were not taking the drug. Fifty-nine percent of respondents would recommend an ophthalmic evaluation for patients with a history of cataracts or decreased vision before initiating treatment with tamsulosin. Nearly two-thirds of respondents said they would avoid taking the drug if they themselves had a cataract or would have their cataract removed before starting the drug. Complete survey results appear in a special report (9-page PDF; About PDFs) in the July issue of the Journal of Cataract and Refractive Surgery.

"We're not presenting the member survey as a level I scientific study," Chang says, "but it does provide a snapshot of cataract surgeons' clinical experience with IFIS and points to their diversity of opinions and experiences with a variety of surgical problems that alpha blockers cause."

For patients with cataracts who are already taking alpha blockers for a health condition, "there's no evidence that switching or stopping the drug would be helpful," says Chang. "Interestingly, IFIS can occur one to two years after tamsulosin has been stopped. Cataract surgery can still be done with a good prognosis, but it's important for the surgeon to know about current or past alpha blocker use. The surgeon then can be prepared to deal with IFIS by using one of several alternative small pupil management strategies."

What about patients with cataracts who aren't taking alpha blockers but who may need to start them? "If the cataracts are to the point where surgery might be an option, we are asking the prescribing physician to consider involving the cataract surgeon before the decision is made to start an alpha blocker. The eye surgeon can assess not only how advanced the cataract is, but also how much risk an alpha blocker might add, particularly in light of other comorbidities. There's lots of variability in how complicated different cataract surgeries might be, depending on density of the lens and other individual risk factors," Chang says.

"Ophthalmologists truly respect how many different things a family physician has to juggle in managing the patient's medical problem list, and we don't want to arbitrarily increase that burden unnecessarily," Chang adds. "Ophthalmologists are ready and willing to take on the process of educating cataract patients about IFIS. We'd welcome the opportunity to be a resource for family physicians and their patients on this issue."