Which BPH medication is most commonly associated with floppy iris syndrome?

Which BPH medication is most commonly associated with floppy iris syndrome?

• A. Prazosin
• B. Terazosin
• C. Tamsulosin
• D. Doxazosin

Answer: (C)

A key concept here is how blocking certain alpha-1 receptors can affect the iris during eye surgery. Floppy iris syndrome occurs when the iris dilator muscle loses tone due to alpha-1 blockade, making the pupil harder to control and more prone to billowing during cataract extraction. Tamsulosin stands out because it is highly selective for the alpha-1A receptor subtype, which is abundant in the iris dilator muscle as well as the prostate. This strong, targeted blockade reduces iris tone and predisposes to floppy iris during surgery more than other alpha-1 blockers. Other BPH medications, such as prazosin, terazosin, and doxazosin, block alpha-1 receptors but are less selective for the alpha-1A subtype. Because of that broader activity, their association with floppy iris syndrome is weaker, even though it can occur. In practice, the risk is highest with tamsulosin, which is why it’s the drug most commonly linked to this complication.

A key concept here is how blocking certain alpha-1 receptors can affect the iris during eye surgery. Floppy iris syndrome occurs when the iris dilator muscle loses tone due to alpha-1 blockade, making the pupil harder to control and more prone to billowing during cataract extraction. Tamsulosin stands out because it is highly selective for the alpha-1A receptor subtype, which is abundant in the iris dilator muscle as well as the prostate. This strong, targeted blockade reduces iris tone and predisposes to floppy iris during surgery more than other alpha-1 blockers.

Other BPH medications, such as prazosin, terazosin, and doxazosin, block alpha-1 receptors but are less selective for the alpha-1A subtype. Because of that broader activity, their association with floppy iris syndrome is weaker, even though it can occur. In practice, the risk is highest with tamsulosin, which is why it’s the drug most commonly linked to this complication.