An international shortage of drugs used to treat leukemia, ovarian and lung cancers is leaving Edmonton doctors and pharmacists scrambling even though the province says patients won't notice the problem.

The province was alerted to the shortage a few weeks ago. Doctors will substitute the drugs with similar ones that are not in short supply.

"We think we have the situation under control and we believe that we're adequately, satisfactorily, adequately, treating patients despite this shortage," said Dr. Paul Grundy, director of cancer care for Alberta Health Services.

That's being challenged by some Edmonton oncologists who said while replacement drugs are unlikely to affect patient outcomes, they will make treatment more challenging.

"Replacement drugs will have different side effects and may require more treatments," said oncologist Dr. Katia Tonkin. 

"More vomiting, or more issues monitoring the kidney function or things like that or having to have extra cycles of treatment," she said. "That's obviously a quality of life issue, which is not at all insignificant.

"If I was a patient I wouldn't be too happy."

Tonkin expects to begin using alternate drug treatments on new or relapsed patients as soon as next week.

The national inventory should be back to normal by mid-June, health officials said.

But with the worst shortage in three decades, Tonkin predicts the problem won't go away any time soon. She said a national agency should be created to prevent future shortages.