Modern medicine relies heavily on the most advanced drugs to treat patients for a range of maladies.

Unfortunately, as the Los Angeles Times reports, a growing list of drugs are in short supply, making this more difficult.

According to surveys from the University of Utah, the number of shortages spiked to 211 last year, up from 58 in 2004. This year, as of the end of March, already 89 medications are in short supply.

The drugs on the list aren’t just minor and easily replaceable painkillers, but often critical, life-saving medications. For instance, leucovorin, a vital element for top-of-the-line colorectal cancer treatment, has been in severe shortage since 2008.

From the drug companies’ perspective, the problem is one of economic incentives. Many life-saving drugs simply are not prescribed often enough to bring in the billions of dollars that others do, and drug makers often decide that it’s better to shift their resources elsewhere.

The Food and Drug Administration is the governmental body that theoretically manages the supply of essential drugs, but the agency is limited by a lack of regulatory clout and timely information.

Drug companies are required to give advance notice of the discontinuation of a drug only if it is considered “medically necessary,” a subjective designation that does not, in practice, encompass many medications that patients and their doctors would consider absolutely crucial.

For other drugs, the hospital, patients and the government all learn about the discontinuation after the fact, and without the chance to set up alternatives or prepare for the inevitable shortage.

Valerie Jensen, head of the FDA’s drug shortage program, told the Times that her department will seek to persuade the drug makers to continue making a certain medicine, but “if they refuse to reconsider, there’s nothing we can do.”

A partial fix to this problem has been proposed by Sens. Amy Klobuchar, D-Minn., and Bob Casey, D-Pa., that would require pharmaceutical companies to give the FDA advance warning of any looming shortage, regardless of the reason. Failure to comply would be penalized by a fine.