Z-pack for Strep Throat? Hmmmm. I think he/she should have probably went in the direction of a broad-spectrum antibiotic, i.e. Amoxicillin vs. Zithromax. I have seen Zithromax ordered for Strep Throat, but not that often.
Z-packs (azithromycin = Zithromax) have worked quite well for my daughter's strep infections.
Z-pac is usually a five day course of antibiotic that lasts for ten days. I would recommend that if you are not feeling better by day five that you go ahead and call the dr's office and see what they recommend. You definitely want the infection to be gone by the time your antibiotic stops working. Some people take a steroid to help with the inflamation in the throat. my daughter used a prescription gargle Q-dryl/dexamethasone which has an antihistamine and some sort of steroid in it to help her throat heal faster. The dr also prescribed an anesthetic lolly pop which she said only made her tongue numb. Maybe she didn't suck on it enough though because the pharmacist said to only take a "few licks" and then wrap it back up for a while.
I hope you get well soon.