 [ Symptoms ] can a z pack trigger an alergic reaction i was never allergic to a medication before but 15 days ago went thru a c section i suffered complications and had to receive multiple transfusions and had to get opened back up in order to stop the bleeding cause by a boggy uterus i was taking percocet ibuprofen iron and stool softner ad recently switched out the percocet for vicotin and started a z pack i started having either hives or a rash that is severly itchy on my and now have achy joints what could be the cause [ Disease ] yes a z pac can cause hives or rashes as i know from first hand experience when i was younger i was prescribed amoxicillin when i had strep throat and an hour or so after taking it i broke out in hives and had to go to the hospital oddly enough i have taken amoxicillin when i was sick prior to this experience with no allergic reaction i recommend trying a different antibiotic since there are plenty out there hope this helps