Can an employer review my prescription drug history and others in the community without being her patient

First, it's "HIPAA," not "HIPPA."

HIPAA is all about requirements for medical professionals to safeguard individuals' medical information. It would be a violation of HIPAA rules for a professional such as your doctor, pharmacist, or medical insurance company to release your prescription information to your employer without your consent. But there is nothing that prevents your employer from asking you for consent to review your prescription history - is that what happened?

Some more background would help. As noted HIPAA protects patients from having their medical info revealed by people providing care. Unless you work for a medical practitioner who is also treating you, Your employer doesn't fall under HIPAA rules. However, there is nothing wrong with your employer asking for a lit of prescription drugs you take, maybe even require it if your job makes that important. But the info should be kept confidential from others.

Consider HIPAA like doctor/patient privilege. Is the employer a doctor? Has said doctor given information to others without implied consent?