Many people take drugs that interfere with their blood pressure pills

On a related matter, many patients self-prescribe medicinal herbs, some of which can interact with prescribed medicines.

Patients who need blood pressure medicine should ask their doctor if any of the other medications they’re taking might interfere.

How come it's the patient's responsibility?

Most Japanese doctors I've been to, when asked about the medication they are happily prescribing for you, look at you with an attitude of "And what would you, a complete idiot need to know that for?