Linda Broyles,

Thanks for your question.

The combination drug for high blood pressure, lisinopril 20mg/hctz 12.5mg (brand names Prinzide, Zestoretic), is not a time release preparation.  Should you cut the pill in half, each part will have both portions of the drug, but half the total dosage. 

Be sure your doctor is aware of any change in the dose of any medication.  If you are considering breaking the tablet to take twice a day instead of once a day, remember that the diuretic portion, though a very small dose, will be active up to 6 - 8 hours after taking the medication, and therefore, depending on your response, may be an issue during sleep.  Again, this should be discussed with your physician.

Best wishes. 

Martin Cane, M.D.