Flowmaxtra and the Floppy Iris

People often ask me why they need a current referral to see an ophthalmologist. The bureaucratic answer is that without a referral you can’t access the medicare rebate, but this may actually be the least important reason. Many people find it hard to remember details of their medical history, or their current (and past) medications. And it may not be immediately obvious which of these details are significant for their eye health.

This was brought home to me the other day when I performed cataract surgery on someone who had been taking Tamsulosin. He hadn’t recalled this medication when I’d talked to him, but thankfully it was recorded on his referral. 

Tamsulosin, available in Australia as Flowmaxtra (CSL), is used to treat Benign Prostatic Hyperplasia (BPH), a condition that affects middle aged and older men by causing urinary hesitancy, painful urination, and even urinary retention. What could this possibly have to do with cataracts? Well, Flowmaxtra can cause the iris to behave oddly during cataract surgery, sometimes with catastrophic consequences, in what is known as the “intraoperative floppy iris syndrome” (IFIS). IFIS can lead to serious sight-threatening complications because cataract surgery is technically complex, and each subsequent step depends on the success of the previous step. A population-based study performed two years ago in Canada, which included all men over 66 that had cataract surgery in Ontario over a 5-year period, found that complications occurred more than twice as often in men using Tamsulosin. More than 50 000 scripts are written for it annually in Australia.

The American Society of Cataract and Refractive Surgery (ASCRS), which I belong to, has tried to encourage GPs and Urologists to consider other medications for BPH, or to refer prospective patients for an eye examination so that if necessary their cataracts can be removed prior to starting the drug. 

But the most important thing is that the ophthalmologist be aware if a patient with cataracts uses Flowmaxtra. The good news is that if the ophthalmologist knows a patient is using Flowmaxtra, steps can be taken to avoid or limit the risks associated with IFIS. And this is a great reason to have a current referral.

(CM Bell et al. Association Between Tamsulosin and Serious Ophthalmic Adverse Events in Older Men Following Cataract Surgery. JAMA 2009; 301(19): 1991-1996.)

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