Just curious how long I can use PZI once it has been opened. My cats BS have seemed to increase (from a stable 200-250 PS to now 300-350) I'm wondering if I need a new vial. I opened it about 7 months ago and it has an expiration of 4/21. Thanks.
ProZinc is good for 5-6 months after opened as long as you keep it refrigerated. If youre noticing it's not as effective I would get a new vial.