One of the worst drug shortages facing US hospitals was reported in 2001, and was not expected to be the last. Shortages of medications that hospitals use every day were apparently occurring with more frequency and they more often involved products with few good alternatives. Examples were the tetanus vaccine, intravenous Isuprel (to revive cardiac arrest victims); Wydase (to numb eyes for cataract and other surgeries), the painkiller fentanyl, and Narcan (used to reverse morphine overdoses). Shortages encouraged price increases, sometimes a doubling of the cost. At the same time hospitals are keeping less inventory than ever before, sometimes only enough for a few days. Reasons for the shortages were companies suddenly deciding not to make the drug or a crucial ingredient for a drug, temporary rises in demand, production halts through discovery of health-threatening violations in a factory and a decrease in replacement medicines due to drug company mergers. The US Federal Drug Authority (FDA) and Centres for Disease Control (CDC) were studying which critical drugs are most at risk for shortages. FDA officials were trying to ease the situation by finding overseas ingredient suppliers or encouraging small drug companies to make drugs a larger company has decided to cease production of. A system of Internet bulletins is being developed warning of impending shortages and listing any alternatives.