Tamsulosin, an α1-adrenergic blocking agent, is prescribed for symptoms of benign prostatic hypertrophy. In 2005 over 1.6 million prescription items of tamsulosin were dispensed in England.1 Intraoperative floppy iris syndrome was first described in the medical literature in April 2005,2 and there have been 16 subsequent related peer-reviewed publications. There is, however, no mention of the association in the current edition of the British National Formulary.3 Intraoperative floppy iris syndrome occurs in approximately 2% of all cataract-surgery patients and is characterized by billowing and prolapse of the iris through the corneal incisions and progressive pupillary constriction. This leads to a more complex surgery and a higher rate of complications.4 Many eye units now advise patients to discontinue tamsulosin for 2 weeks before cataract surgery and to start taking it again immediately after surgery, though the syndrome can occur in patients who stopped therapy 1 year before surgery. The condition is associated with all the α1-adrenergic blocking agents but is much more commonly seen with tamsulosin, which is highly selective for the α1A receptor. These particular receptors are present in bladder-neck smooth muscle and in the iris dilator muscle. Blockage of this latter muscle allows unopposed action of the parasympathetically innervated iris constrictor muscle and loss of iris tone, resulting in the clinical syndrome. Intraoperative strategies for reducing the risks during surgery have been described and include the use of iris hooks (Figure 1) and intracameral phenylephrine.5
We would like to raise awareness about this condition among primary care physicians and to advise that the use of α1-adrenergic blocking agents should be documented on referrals for cataract surgery. Such patients are at higher risk of problems both from cataract surgery and from the urologic effects of the temporary cessation of treatment.
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