Taxing medical marijuana is "discriminatory" according to a group of 50 Canadian doctors that want the federal government to scrap plans to charge cannabis patients. They say that scheme is both unfair — because nobody else in the country has to pay tax for their medicine — and also dangerous since preventing patients from accessing marijuana could force them to use harmful alternatives.

"The new taxes being proposed on medical cannabis [are] discriminatory towards patients," Dr. Michael Verbora said in a recent statement. "All medications prescribed have zero tax."

Dr. Verbora — who is the medical director for the cannabis advocacy group Canabo Medical Clinic — added that taxing medical marijuana could exacerbate the opioid epidemic by putting financial barriers around a safer alternative to addictive painkillers like percocet.

"At a time when we are suffering from an opiate crisis the last thing we should do is introduce financial barriers to patients accessing a safer alternative," Verbora added.

But Ottawa insists that the extra charge is needed to keep people from becoming medical marijuana patients for the sake of cheating the taxman.

"[W]e do not want the taxation levels to be an incentive for people to utilize that system inappropriately and so we propose that the taxation levels for both non-medical and medical will be aligned," Parliamentary Secretary Bill Blair said last month.

But there already is a process in place to weed out dubious patients. Under current regulations, patients have to get their cannabis recommendation renewed by a physician periodically. The longest a person can go between recommendations is 12 months, so doctors will have a chance to reassess the needs of their patients at least once a year. That means doctors can easily cut off anyone who is abusing the system.

Of course, there might be an ulterior motive for the federal government's plan. At least one industry insider projects that there could be 2 million medical marijuana patients in Canada by 2030. And that would generate an awful lot of potential revenue for the government.