Multiple issue here which need to be addressed rather quickly.
1.patient dizzy spells could be because of combination of anti hypertension
medication he is taking.
2.His raised urea and creatinine
could well be because of ACE inhibitors or they could be result od CCF itself.
3.Use of voltral is not good choice.
4.in first instance I suggest stop voltral and ACE inhibitors ,check urea and electrolyte 1 week after stopping these drugs and let me know.
5.please arrange Holter monitor
for 24 hours.
6.also check the patient lying and standing BP for three days and let me know.