Can A Double Prescribed Amount Of Cogard / Nadalol, Or

Can a double prescribed amount of Cogard / Nadalol, or any other blood pressure medication, SAFELY be cut in half for the correct dose? I have always been told to NEVER cut blood pressure medications for a smaller dose as there is NO accurate way to ascertain that the correct amount of medication is given per dose. This is one of two BP meds, 10 Mg./D Lisinopril is the other BP med., my husband takes for Portal hypertension and to help control a slowly growing Aortic Aneurysm.