Just one dose of tamsulosin is enough to cause complications for cataract surgery
Ophthalmologists are calling on doctors for their help in avoiding complications from floppy iris syndrome, caused by popular medications for an enlarged prostate.
In relaxing the bladder and prostatic smooth muscle, alpha-1 adrenergic receptor antagonists, such as tamsulosin, also relax the dilator muscle of the iris.
With an ageing population, the prescribing of tamsulosin and the need for cataract surgery are both rising, prompting the renewed push to raise awareness of floppy iris syndrome.
And it was not only a concern for patients who were current users of tamsulosin, Sydney ophthalmologist Dr Neil Rowe said.
“You can have one dose of tamsulosin in your lifetime and years later you can develop this complication,” Dr Rowe told The Medical Republic.
Dr Rowe said he saw at least three or four patients a year with floppy iris syndrome, and research suggested between 40% and 90% of patients who had taken tamsulosin developed the condition.
Alerting the surgeon to the patient’s history of tamsulosin use allowed them to prepare alternative management options and could greatly improve the outcome of the operation, Dr Rowe said.
Studies suggest that the complication rate with undiagnosed intraoperative floppy iris syndrome can be as high as 12%, but can be reduced to 0.6% when the surgeon is aware of the patient’s past or present use of the drug.
Without forewarning, patients are at an increased risk of complications such as blurred vision, oversensitivity to light and difficulty driving at night.
“It makes the operation technically much more challenging when it suddenly happens halfway through a procedure, and being prepared and aware of it is very helpful,” Dr Rowe said.
With floppy iris syndrome, instead of having a clear operating field to work with, the iris can become mobile and protrude from the wounds made in the cornea, Dr Rowe said.
“It can be imbricated and sucked into the operating handpiece tip, and cause trauma for the patient,” he said.
“Often the pupil will become smaller during the procedure, which drastically limits what you will actually see during the cataract operation.”
Dr Rowe said generally a patient’s eyesight was going to be very good after a cataract operation, but with floppy iris syndrome the patient could end up having a much more painful eye, with increased inflammation, and a more prolonged recovery.
In 2014, the Royal Australian and New Zealand College of Ophthalmologists (RANZCO) issued a warning about the potential problems intraoperative floppy iris syndrome could cause in cataract, glaucoma or some forms of refractive surgery for some patients.
In a survey of ophthalmologists, 95% said they believed tamsulosin made cataract surgery more difficult and 77% said the drug increased the risks of surgery.
In Australia, medications including tamsulosin are Sandoz SR, Duodart and Flomaxtra.
RANZCO listed other medications with the potential to cause the syndrome, including alfuzosin (Xatral), terazosin (Hytrin) and doxazosin (Carduran) also used to treat BPH; prazosin (MiniPress) and labetolol (Presolol, Trandate) used to treat hypertension; and risperidone (Risperdal), ropinirole (Rep reve), and mianserin (Tolvon, Lumin) used for treatment of some psychiatric conditions.
The herbal preparation Saw Palmetto may also put patients at risk.
A spokesperson for Duodart manufacturer GSK said it was important for doctors to be aware of the risks, and to encourage patients to talk about their medicines prior to surgery.
