Over the past few years, hundreds of drugs have been in short supply in Canada, from antibiotics for minor infections, to lifesaving chemotherapy or epilepsy drugs. But the shortages are also affecting those who rely on vitamin B12.

Moncton, N.B. resident Louise Levesque is one of those affected. She has trouble absorbing B12 through food so needs monthly injections of the vitamin to avoid a deficiency.

The problem is that there are shortages of the vitamin across Canada. Levesque hasn't had a B12 injection in close to two months and says she's feeling the side effects.

"I'm more tired, more anxious. And I work with kids, so of course I need all my energy," she tells CTV Atlantic.

It's estimated that as many as five per cent of Canadian adults have a vitamin B12 deficiency. The most common cause is pernicious anemia, a condition in which people lack a key stomach protein that allows them to absorb the vitamin from food.

Deficiencies are also common among vegans who don't take supplements, people taking certain medications, and among those who suffer from celiac or Crohn’s diseases.

Without vitamin B12, the body has trouble building the red blood cells that carry oxygen and allowing the brain and nervous system to function properly. The result is a feeling of chronic fatigue.

For some, taking high doses of a B12 supplement is enough, but for others, the best treatment is injectable B12 injections. Yet the country has been dealing with shortages ever since drug maker Sandoz Canada had to close a manufacturing plant in Quebec in February, 2012, to upgrade it to meet U.S. Food and Drug Administration standards.

The only other injectable B12 manufacturer in Canada tried to pick up the slack from the closure, but there has been too much demand to catch up, leading to shortages across Canada and the U.S.

Moncton pharmacist Pierre LeBlanc says the shortage is an ongoing problem.

"People are coming to our store wanting their medications and we say, 'Well we can't.' And they say, 'Well can we go somewhere else?' 'Yes, you can go somewhere else but they still don't have it'," he tells them.

Levesque's doctor tells her she has a two-month grace period for skipping her injections, and with that period running out, she's getting anxious.

"As much as I hate needles, I would like to be able to start back having my injection, before it brings more health problems," she says.

Sandoz Canada states on the DrugShortages.ca website that expects to release a batch of B12 at the end of the month.

For now, Levesque and others like her have no choice but to wait until April to see whether the suppliers will deliver.

With a report from CTV Atlantic's Sarah Plowman