On June 5, 1984, Ronald D. Kay received U.S. Patent No. 4,452,364 on a Safety Closure Device for Medicine Container:

Perhaps inspired by the infamous Chicago Tylenol murders just months before he filed his application on February 7, 1983, Kay provided a medicine container that could not be opened without revealing that the container had been tampered with.

Since 1976 more than 8000 U.S. patents have issued on tamper indicating packaging. Necessity is often the mother of invention, although in this case the necessity is sad (and disappointing).