It's a reasonable question to ask. But I have frozen OTC meds of all sorts and they worked fine for weeks/months afterwards. As with excessive heat and excessive humidity it may reduce the shelf life, but that's assumed with all med's in portable kits.

BTW, I chat up the pharmacist (not the assistant) and make sure I get their newest stock. They never give me a hard time when I explain the intended use. (The pharmacists are almost always intelligent, engaging females; but that has no bearing on the issue, or the chatting up. ;-)