Some drugs used to treat cancer, infections and other ailments in hospitals could be in short supply, Health Canada says.

Health Canada sent letters to chiefs of medical staff, dated Wednesday, to notify them of a potential shortage of drugs produced by Ben Venue Laboratories of Bedford, Ohio, which the department calls a large contract manufacturer of "injectable and inhalational sterile drug products."

Drugs in short supply include those used to treat leukemia, breast and ovarian cancer and other tumours and sarcomas. (J. Scott Applewhite/Associated Press)

The list includes 17 drugs used to treat leukemia, breast and ovarian cancer and other tumours and sarcomas. Some are radioisotopes used in nuclear medicine tests such as heart stress tests, while others are antibiotics given by injection to treat serious infections in hospital.

Health Canada said its recent assessment identified deficiencies in manufacturing at the company's plant, so only drugs deemed medically necessary from the plant can be imported.

But the supply of those drugs could be affected by manufacturing problems.

Advance notice

Many of the drugs affected by the notice are deemed “non-medically necessary,” which means there are alternatives available or deal with non-life-threatening conditions.

For drugs that are considered “medically necessary,” Health Canada said it has a process in place to allow these drugs to continue coming into the country while the manufacturing problems are addressed.

"Health Canada gave medical professionals a heads-up that we had concerns, so they wouldn’t be caught off-guard and that patients could get the care they need," Olivia Caron, a media relations officer for Health Canada, said in an email on Thursday.

While no specific risk to health from using the drugs has been found, the manufacturing deficiencies "raise concern about product quality," Health Canada said.

Canadian doctors and pharmacists have been clamouring for advance notice of shortages through a central registry, as exists in the U.S. They say a registry wouldn't solve the supply problems, but it would help hospitals to plan better.

In December 2010, a survey by the Canadian Pharmacists Association suggested medication shortages have become a serious problem for patients, doctors and druggists.

Nearly 94 per cent of pharmacists surveyed said at the time said they had trouble finding medications to fill a prescription in the previous year.

Reasons for shortages

Shortages of both hospital medications and prescriptions filled at community pharmacies can be caused by a variety of problems along the drug supply change, including:

• Manufacturing problems.
• Supplies of raw materials.
• Companies that cease making a drug that has become less profitable.

Jason Kurtz, associate director of communications for Ben Venue, said unplanned down-time and capital improvements, such as the construction of a new facility used to manufacture chemotherapy drugs, can also contribute.

"As a company, we continue to face manufacturing capacity constraints that are resulting in back orders of some products, and we are working diligently to prioritize and expedite manufacturing for all current orders," Kurtz said.

" We are working to increase manufacturing capacity to ensure Ben Venue can meet our customer's demand and are committed not only to ensuring a continued product supply but to keeping our customers informed regarding order status and expected release dates."

With files from CBC's Valerie Boyer