Inverse benefit law
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. As effectiveness becomes more diluted, the risks of harmful side effects proliferate, 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. 
State of affairs 
The law is manifested through 6 basic marketing strategies:
- reducing thresholds for diagnosing disease,
- relying on surrogate endpoints,
- exaggerating safety claims,
- exaggerating efficacy claims,
- creating new diseases,
- encouraging unapproved uses.
Many harms of new drugs are unexpected, and could be as serious as death. This is the reason why organizations like "Worst Pill, Best Pill"  recommend not to use/prescribe new medications before being in the market for at least ten years (except in the very few cases of very important new drugs that solve previously unsolved problems).
Agencies of drugs, committee of ethics and organizations of patients' safety should consider:
- Requiring that clinical trials run long enough to pick up evidence of side effects and record all adverse reactions, including in subjects who drop out.
- Paying companies more for new drugs in proportion to how much better they are for patients than existing drugs, and marketing according to the value of the new drugs (ratio of benefits to harms and marketing).
- Considering that market could be a force against the best use of medications.
- Brody H, Light DW. The inverse benefit law: how drug marketing undermines patient safety and public health. Am J Public Health. 2011; 101(3):399-404.
- Tanne JH. “Inverse benefit law” explains how drug marketing undermines patient safety. BMJ. 2011; 342:d598.
- Worst Pill, Best Pill. Public Citizen's Health Research Group.
- Wood AJJ. The Safety of New Medicines: The Importance of Asking the Right Questions. JAMA. 1999; 281(18):1753-4.
- Astellas' lawsuit against Prescrire: French court rules that Prescrire did not "denigrate" Protopic° (tacrolimus). Prescrire. 2 March 2011
- Gérvas J. Garum. Acta Sanitaria. 07/03/2011.
- Light DW (Editor). The Risks of Prescription Drugs. New York: Columbia University Press; 2010.
- Evans I, Thornton H, Chalmers I. Testing Treatments: Better Research for Better Healthcare. London: Pinter & Martin Ltd; 2010.
See also 
- Disease mongering
- Health policy
- Inverse care law
- Patient safety
- Pharmaceutical company
- Pharmaceutical marketing
- Public health
- Quaternary prevention
- Medical science liaison