Suddenly Anti-Antibiotic

Customer: “Hi, I’d like to fill this prescription, please.”

Me: “Very well, I’ll need your birthdate.”

Customer: “[Birthdate]. Hurry up, please.”

Me: “Any known allergies?”

Customer: “What? No! Look, it’s not my first time taking these pills. Just give it to me.”

Me: *taken aback* “Okay, sir, you may go in the waiting room.”

(A few minutes later the pharmacist explains the treatment to the customer.)

Pharmacist: “So, those pills are penicillin combined with another antibiotic—”

Customer: “Penicillin? What? I can’t take this! I’m deathly allergic to penicillin!”