past frequent nightly urination
Great question, and one that I'm not finding a good answer for after reading the complete drug manufacturer's "Patient Information" sheet found here:
The most I get from this (in relation to your question) is that a person might consider the possible increase in risks for side effects when using this (or any) drug for an extended period of time. However, it's best to discuss this, and any medication-related question, with your doctor directly.
I hope this was somewhat helpful to you. If you find out more specific information, please share it with us.