You do not want to get any moisture onto the other remaining pills in the bottle as they will turn to powder. Also, once this bottle is opened, the shelf life
decreases. I get 25 pills per bottle and have had to only open one bottle so far. They are fairly cheap to buy. I buy a package with 4 little bottles in it.
Also, yes, you can feel lightheaded and also get a headache after taking a nitro but this sure is better than these %^%&^$^%$& stomach attacks.