How property rights and patents affect antibiotic resistance.

Antibiotic resistance tends to increase when a patent on an antibiotic expires. Since other companies can now sell the antibiotic, more of the antibiotic is produced and prices fall. Because the benefits of reducing current production go to other firms, pharmaceutical companies will have little concern about future resistance. This 'open-access' problem causes excessive antibiotic use and resistance problems in the future. Extending patents is one solution. However, a pharmaceutical company that has patent protection on a drug that is cross-resistant may have little concern about future resistance. This is because when people use completely different antibiotics which cause bacteria to become resistant to the original antibiotic, then the benefits of reducing current production go to other companies. A single buyer such as national health insurance or private health insurance may also have an incentive to reduce antibiotic resistance since they bear the future cost of future resistance. However, insurance coverage reduces the price that patients pay at the margin and thus the patients are likely to use more antibiotics. National health insurance policies may even set the price of antibiotics so low that resistance problems are created even when the patent is in effect.