One of the world’s biggest prescription drug categories is moving otc in Canada and is expected to shake up the marketplace.

These new products, known as H2 blockers or acid blockers, are in direct competition with antacids – which at $100 million is Canada’s third largest otc category.

In prescription form, H2 blockers are used as anti-ulcer drugs but their lower otc dosages are used to relieve and prevent heartburn and acid indigestion.

If the u.s. experience is any indication, the introduction of H2 blockers into the mix will increase the antacid category by roughly 60% and the new products will control about one-third of the market.

At the time of the u.s. launch last June, the antacid category was worth us$800 million.

Figures this May put the category at us$1.35 billion.

While there are four brands in the H2 blocker segment in the u.s., the scenario in Canada could be much different.

The Waxman-Hatch Act in the u.s. allows branded otc products three years of exclusivity.

Canada has no such law, and that leaves the door open for generics and store brands to enter the market at the same time as the name brands.

Toronto-based Novopharm has the generic rights to the prescription forms of the three leading brands in various parts of the world.

Novopharm is the parent company of Wampole Canada, a branded otc company with a line-up of analgesics, vitamins, minerals and herbal remedies, and Stanley Pharmaceuticals of Vancouver, a manufacturer of generic otc drugs such as store brands.

Aubrey Dan, president of Wampole, would not comment on the company’s plans for the H2 blockers category.

The first of the new branded products, Pepcid AC from Johnson & Johnson-Merck Consumer Pharmaceuticals of Canada, is appearing on store shelves now and will be followed in a few months by Tagamet HB from SmithKline Beecham Consumer Healthcare.

Advertising campaigns for the products are scheduled to coincide with product availability.

Warner Wellcome Consumer Health Products says the introduction of Zantac 75 is imminent but would not be more specific. Zantac 75 is the otc version of Zantac, the largest selling drug in any category in the world.

The Canadian rollout seems to be following the same sequence as in the u.s.

Pepcid AC was first off the mark last June with Tagamet HB entering a few months later.

Zantac 75 was not introduced until April of this year.

All three brands were launched with a us$100 million marketing campaign.

Saatchi & Saatchi, the agency for Pepcid AC in the u.s. also has the business in Canada.

J. Walter Thompson has Zantac 75 in both countries.

SmithKline Beecham Canada’s agency, Grey Canada, has the Tagamet HB account here, although it is with Ogilvy & Mather in the u.s.

The fourth player in the u.s. market is Axid AR from Whitehall-Robins Healthcare, which launched in May with a campaign from Young & Rubicam, New York. A budget figure was not disclosed.

Whitehall-Robins’ plans for Axid AR in Canada are also not known.

Although the four new acid-blocking products are in the same category, they do not have the same efficacy.

Pepcid AC and Tagamet HB have been approved for both prevention and relief of heartburn which means they can be taken an hour before meals to prevent heartburn or afterward to relieve symptoms for up to nine hours.

Zantac 75 and Axid AR are designated as relief products only.

Kevin Foley, marketing manager at SmithKline Beecham, says the u.s. antacid category has Pepcid AC in first place with a 13.4% share, Zantac 75 in second place, followed by Tums (another skb brand) in third, and Tagamet and Mylanta in a race for fourth.

He doesn’t believe the standings will be the same in Canada because in the u.s. Mylanta – which is owned by J&J-Merck – is a different formula than in Canada where it has a share level of between 1% and 2%.

‘In the u.s., we’ve seen that Tums has made a slight increase in its business and our product Gaviscon has also grown,’ says Foley.

‘Other brands such as Maalox, Mylanta, Rolaids, Pepto-Bismol have all declined.’

Johnson & Johnson-Merck and SmithKline Beecham are putting a heavy focus on information during the launch phase.

Each will have 1-800 consumer information lines and are working closely with pharmacists and doctors to make sure consumers use the products as directed.

The 1-800 lines will help consumers identify whether their symptoms should be treated with otc products or if they should see their doctor.

Concerns over misuse of H2 blockers were voiced when the products were in the application stage of otc approval from the Health Protection Branch of Health Canada.

It was felt that use of H2 blockers could mask signs of more serious problems such as ulcers, stomach cancer and heart disease.

Helene Carty, spokesperson for J&J-Merck, counters this criticism by saying, ‘H2 blockers in the marketplace will replace products already available, the antacids, but they offer better control of acid production.

‘The product has a limited usage date of two weeks of constant use. It would not be potent enough to mask symptoms of ulcer and any recurrent symptoms should be seen by a physician.’

The cost of H2 blockers should also be a deterrent to misuse.

A package of six tablets of Pepcid AC will range from $3 to $4 while a 12-pack could be from $7 to $8.

To equal the prescription dosage would mean taking six to eight tablets per day.