B.C. pays doctors a flat fee for treatment of macular degeneration, but pocket far less money if they choose the drug considered more effective. (CBC)

British Columbia's plan to pay for an expensive drug used to treat age-related macular degeneration may be putting doctors in a conflict of interest, CBC News has learned.

Starting Monday, the B.C. government will begin paying for Lucentis, a costly drug that has been shown to halt and even reverse one form of the disease that attacks the retina.

The disease is the leading cause of blindness in people over 50 and affects more than 3,000 British Columbians.

There are two main drugs to treat age-related macular degeneration, both injected directly into the eye.

Lucentis is approved for treating the condition and costs $1,800 per single-use vial. Avastin is chemically related, but was originally designed to treat colon cancer intravenously. Doctors in various jurisdictions are using it off-label for AMD at a cost of a $12 to $15 per dose, and charging $300 to $500 per injection.

The B.C. government's solution is to pay doctors a fee of $530 every time they do the five-minute procedure, regardless of which drug they use.

The plan was designed to take worries about the cost of the drugs out of a patient's hands and into that of the doctors who procure the medications.

A physician who prescribes Lucentis will see little profit. If it's Avastin in the syringe, the doctor keeps more than $500 per injection.

Expert recommends more expensive drug

Dr. Neil Bressler of Johns Hopkins University in Baltimore, Md., who led clinical trials of one of the first treatments for macular degeneration a decade ago, agreed the B.C. plan is potentially unethical. There's no medical reason to use the cheaper drug, he added.

"The evidence is stronger to use Lucentis than Avastin at this time," Bressler said, noting doctors should be sharing that information with their patients before giving the injections.

Last year, a federal body that reviews medications recommended that provincial insurance plans pay for Lucentis.

Dr. Derek Godinho, a retinal specialist in North Vancouver who worked with the government on the program, wouldn't talk about the financial details. He rejects any idea it puts doctors in a conflict of interest.

"You have to presuppose that doctors are going to be unethical if you want to use that argument, and I absolutely reject that."

The potential conflict of interest is significant, said Dr. Jeff Blackmer, the director of ethics with the Canadian Medical Association.

"It's not really a kickback, but it has that sort of feel about it," Blackmer said. "Where if you know you prescribe the less expensive drug you get to keep the money."

Ontario, which began covering the cost of Lucentis last year, pays physicians for the procedure — not the drug.

In a statement, the B.C. Ministry of Health told CBC News that the fees paid to doctors will also go toward their cost of tasks like handling the drugs, and keeping track of their use in a data base.

The department said it has no doubt physicians will act ethically and in the best interest of their patients.