Can anyone find out if a person purchases over the counter controlled substances
1 - If it's a "controlled substance", it's not sold "over the counter".2 - If it requires a prescription, HIPAA laws forbid the pharmacy from giving the information to anyone (other than the insurance company).3 - No store will risk the liability of telling you what someone else purchased, without a court order.
You cannot purchase OTC controlled substances, hence the word "controlled" in "controlled substances." If they're over-the-counter, they're not controlled substances.
Basically, controlled substances are not sold over the counter. A controlled substance is usually a drug or also a chemical whose manufacture, ownership, or also use are regulated by a government.