blood pressure drop after no meds

Hi All,
I am new and apologize for starting out with a question.
That said...

My husband has a history of high blood pressure. Typically around 170/90. With meds (Crestor HCT) it might drop to 140/85 at best. For the last few days it has been 120/80. This is after forgetting to take his meds. The only real change has been adding an alternative nutritional supplement. I am not totally sold that this could be the cause. Today he said his vision seemed a little weird.

Should I be worried about this. Most sites say that a dramatic drop in pressure can be dangerous. But he has gone from high to normal.

Any thoughts on this would be great.