CHICAGO - Hospitals across the country are running out of key drugs used in surgeries and to treat some diseases, including cancer - a shortage that is causing doctors to turn to older treatments.

In some cases, hospitals are paying higher prices to get their patients necessary care because wholesalers are hoarding needed medicines.

Part of the shortage is being caused by manufacturing issues and quality-control problems at a number of companies as they respond to the federal government's drug-safety crackdown.

The quality issues can include toxins and "particulate matter" in medicines and workers inaccurately filling out the required paperwork to verify that the drugs, as well as the devices used to deliver the products to patients, are safe and effective.

"These are the worst shortages I have ever seen," said Thomas Wheeler, director of pharmacy for Advocate Illinois Masonic Medical Center in Chicago and a hospital pharmacist for three decades. "The most troubling aspect is that it is critical drugs for which there are limited alternatives. Many are involved in cancer care and surgery."

About 150 drugs - triple the number from five years ago - are in short supply, according to the American Society of Health-System Pharmacists. About 60 of those are considered by federal health officials as "medically necessary," and they include prescription medicines used to treat or prevent serious diseases or other medical conditions.

Drugmakers say they are following tougher safety rules put in place by the U.S. Food and Drug Administration, which has intensified scrutiny to avoid allowing unsafe medicines on the market.

The drug shortage is being exacerbated by consolidation in the pharmaceutical industry, which leaves fewer companies making drugs.

In addition, some drug companies have stopped making older, generic injectable drugs, which typically aren't as profitable as newer, brand-name medicines. That puts additional production pressure on the remaining makers of generic treatments.

Some hospitals are dealing with the supply problem by turning to older medicines. While those drugs can be just as effective, the lack of familiarity among medical professionals can lead to improperly calculated dosages.

Other medical facilities have turned to secondary suppliers when their primary source for drugs has run out of needed medicines.

This has caused hospitals to pay double or more for certain drugs because they are working with a supplier that normally doesn't supply them with large volumes of a product.