The Prescribing information for Zyflo CR includes:

"Assess hepatic function enzymes prior to initiation of ZYFLO CR, monthly for the first 3 months, every 2-3 months for the remainder of the first year, and periodically thereafter."

In a patient with no suggestion of hepatotoxicity, for routine surveillance, how often do you recommend the "periodically thereafter" be. I was unable to find any specific guidance in the literature. Thank you.


Thank you for your inquiry.

I am afraid that the interpretation of the terminology “periodically thereafter” is left entirely up to the prescribing physician. I am not aware of any consensus as to how often to measure liver function testing after the first year, and could find no such consensus with a search of the literature.

Thus all I can give you is my own personal interpretation of this terminology. I think it would be reasonable to consider measuring liver function tests (specifically ALT) every six months thereafter.

Thank you again for your inquiry and we hope this response is helpful to you.

Phil Lieberman, M.D.

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