seriously, just call poison control center. it is free so you have absolutely nothing to lose. even if you dont think it is a big deal after all call them anyway since it is free.
it is also confidential and if you want it can even be anonymous (just say you dont want to give your name when they ask)... so they wont scoff at you for taking vet drugs.
even if you have already scheduled an appointment with the doctor, i would call poison control center anyway. the doctor will just call them when you get there (that is what they do when the doc leaves the room and make you wait for 30+ minutes.) i would still keep the doctor appointment of course... regardless of what poison control tells you.
if you are not satisfied with the response the poison control operator gives you, or they seem incompetent, or even if you are satisfied with their answer, i would advise calling back at a different hour (when a different shift of operators are in) and get a 2nd 3rd or even 4th opinion. remember it is open 24/7. again it's free and there is nothing to lose, might as well be safe and get several opinions.
also there are different poison control centers than the main hub and you can try local ones. there is also a veterinary poison control center but they cost $65 per call. they might be more informed about z-gold than the human center though.