I was thinking maybe this is why my doctor didn't prescribe niacin with my statin.

I suspect he won't prescribe niacin because you are taking a statin. Doubt it has anything to do with BP meds. My Doctors has me taking 2 different BP meds along with my 3000 mg niacin a day.

There is no problem taking niacin along with blood pressure medications that I know of. I too, take two blood pressure medications (although oddly enough not because of high blood pressure) along with niacin.

Your doctor didn't want to prescribe both. Besides, if you just started a statin, I'm not sure you'd want to take both (not counting possible side effects)... can't tell which is helping that way. Or it could simply be that your doctor doesn't like niacin as a medication. Some family doctors and even cardiologists go to statins first, regardless of lipid numbers.