What is Inverse Benefit Law?

Legal Definition
The inverse benefit law states that the ratio of benefits to harms among patients taking new drugs tends to vary inversely with how extensively a drug is marketed. Two Americans, Howard Brody and Donald Light, have defined the inverse benefit law, inspired by Tudor Hart's inverse care law.

A drug effective for a serious disorder is less and less effective as it is promoted for milder cases and for other conditions for which the drug was not approved. Although effectiveness becomes more diluted, the risks of harmful side effects persist, and thus the benefit-harm ratio worsens as a drug is marketed more widely. The inverse benefit law highlights the need for comparative effectiveness research and other reforms to improve evidence-based prescribing.
-- Wikipedia