Been busy for a few days, dude... Sorry I couldn't respond any sooner.
But you got all the advice you needed from Sam.
Quite true: poppers are metabolized quickly. You can use Viagra without much concern.
One caveat, however... I've had a few instances of "heavy" popper use that resulted in some rather rotten symptoms the following day... you know... headache, lung-ache, that sort of thing. These always go away quickly.
I would personally avoid Viagra or related ED drugs until I felt fine if I were experiencing "popper hangover." Even though your blood pressure is probably perfectly normal with a popper hangover, why push your limits, right?
And like Sam said, the opposite is true: do NOT use poppers until Viagra has worn off. Viagra is supposed to last about four hours, but I'd also personally wait a full day or so just to be extra safe. Other ED drugs last much longer than Viagra -- consult
www.rxlist.com for info on the duration of these drugs, or just have a look at the patient information sheet that comes with them. You can also get a patient information sheet from any pharmacist.