Are there any rules that if a doctor has such a deal, it must be clearly expressed to the patient verbally and in writing? I think that would help not only dete

Are there any rules that if a doctor has such a deal, it must be clearly expressed to the patient verbally and in writing? I think that would help not only deter doctors for making the deal at risk of being viewed as untrustworthy but also help people who blindly trust their doctor to maybe think twice before accepting their solution. I don't think there's a fix for the patients that just want the drug, and as long as they're informed, consenting adults, it should be their prerogative.