My question is: I have used Caverject Impulse 40mcg, once a week for about 6 months. The 40mcg gives me an outstanding erection, but it lasts way to long, right at about 3 hours. I have cut back to using 20mcg and same great erection, lasting about 90 minutes, which is perfect for my partner and I.

My Doctor prescribes me the 40mcg. If I only use 20 of the 40mcg, can I store the remaining reconstituted 20mcg for use at a later date? And, how should it be stored?