Despite efforts by the Obama administration to ease shortages of critical drugs, shortfalls have persisted, forcing doctors to resort to rationing in some cases or to scramble for alternatives, a government watchdog agency said on Monday. At the end of the day, this will translate to increases in medical costs for payment systems including workers’ compensation. According to the article in the New York Times, drug shortages have become an all but permanent part of the American medical landscape. The most common shortages are for generic versions of sterile injectable drugs, partly because factories that make them are aging and prone to quality problems, causing temporary closings of production lines or even entire factories. The number of annual shortages – both new and continuing ones – nearly tripled from 2007 to 2012.

The analysis by the United States Government Accountability Office, released Monday, was required by a 2012 law that gave the Food and Drug Administration more power to manage shortages. The watchdog agency was charged with evaluating whether the F.D.A. had improved its response to the problem, among other things. The accountability office concluded that the F.D.A. was preventing many more shortages now than in the past – 154 potential shortages in 2012 compared with just 35 in 2010 – but that the number of shortages has continued to grow.

“We are at a public health crisis when we don’t have the medicines to treat acutely ill patients and we don’t have the basics like intravenous fluids,” said Erin Fox, a drug expert at the University of Utah whose data was used in report. The most acute shortage now is that of basic I.V. fluids, she said.

The drug industry rarely spells out the precise reason for a shortage, citing its need to protect competitive trade information. Dr. Douglas C. Throckmorton, a senior F.D.A. official who deals with shortages, said in written testimony released on Monday that 66 percent of production disruptions that led to shortages were caused by quality problems and efforts to fix them.

The 2012 law required that drug companies provide the F.D.A. with a general reason, but Ms. Fox said that it was often not specific enough to understand what was driving the shortage.

Economic factors are also contributing to the shortages. Narrow profit margins are making some drug companies reluctant to invest in fixing old production facilities. Dr. Throckmorton compared aging drug facilities to an old car, which requires significantly more upkeep than a new one. Changes in Medicare reimbursement and the role of group purchasing organizations, which buy drugs on behalf of hospitals, could also be contributing, by further reducing prices.

The F.D.A. said in a statement that it is “committed to the prevention of new drug shortages and the resolution of ongoing drug shortages, which remain a significant public health issue in the United States.”