TORONTO - A small but growing percentage of British Columbians who take statins to lower their cholesterol have twigged to the fact that they can save on their medication bills by pill splitting, a new study suggests.

While the researchers only looked at records for statin prescriptions filled in British Columbia, they suggest substantial savings could be made by individuals who pay for their own drugs, by private or government-run drug plans or a combination of the two if the technique were more widely used.

"There are a lot of patients out there who are taking statins who ... could save a lot of money by splitting a larger tablet, or perhaps even moving to a lower cost statin and splitting a larger tablet of that statin and save even more money," said Colin Dormuth, an analyst in the University of British Columbia's Therapeutics Initiative and lead author of the study.

"There's a lot more potential for splitting to occur."

The study, which looked at statin prescriptions filled in B.C. over an 11-year period, was published Tuesday in the journal Open Medicine. Dormuth said he hasn't seen any data on pill splitting in the rest of Canada.

Dormuth and his colleagues found that in 2006, about 4.5 per cent of statin takers in British Columbia were filling prescriptions for a stronger-than-needed formulation of their drug and splitting the tablets, taking half one day and half the next. In the mid-1990s, less than two per cent of British Columbians appeared to be splitting statins.

It seems likely that those who were pill splitting were doing it with the blessing of their doctors, who had to write the prescription for the higher dose formulation. And in fact the study found that 7.9 per cent of the province's doctors wrote half of all prescriptions that were being split.

Dr. Tom Perry, an internal medicine specialist at Vancouver Hospital and Health Sciences Centre, is one of those doctors. He said he sees no harm in pill-splitting and raises the idea with patients for whom he prescribes statins.

"Typically the difference between a split tablet, where there's a little bit more on one half . . . of the tablet than on the next fragment, it can't possibly make any meaningful difference in terms of the drug's effect," Perry said.

"(But) it definitely can to the user's pocketbook. It's very much like buying any other commodity in bulk, whether you buy cereal or flower or rice or sugar.... Most people will buy it in a larger size."

Most statin makers use what's called "flat pricing," meaning stronger doses of the drugs are only slightly more expensive than lower doses.

Take the popular statin Lipitor, for example: Dormuth said a 10-milligram pill costs roughly $1.78, but a 20-mg pill costs only $2.23. Stretching a month's worth of 20-mg pills over two months saves 66 cents a day, plus the dispensing fee for every other month.

Over the course of a year, a person would save $240 on the drug and could halve the amount they spend on dispensing fees as well.

In the United States, where the technique is better known and more widely used, some insurance companies that offer drug coverage encourage policy holders to pill split. Some even offer free pill splitters, devices that can be bought at a pharmacy for a few dollars.

And some facilities run by the U.S. Department of Veterans Affairs promote pill splitting for a number of medications, though not those that crumble easily or have stomach-friendly or time-release coatings.

Likewise, drugs that come in capsules shouldn't be split, said Dormuth, who noted one brand of statin is sold in capsule form.

While Perry suggested a number of different types of drugs could be split, Dormuth and his colleagues only studied the cost saving potential of statin splitting.

They estimated that in 2006 if 20 per cent of all B.C. statin takers used the technique it would have saved a total of $10.5 million. If all eligible prescriptions had been filled this way, $51.4 million would have been saved, they said.

"If one is going to take a drug for a few weeks, say an antibiotic ... if you pay $35 compared with $10 it's not usually a big deal," Perry said.

"But if you're going to take it for years ... or potentially the rest of your life, it's a huge deal, where the cash out of your pocket is after-tax income."

Pharmacologist Dr. Muhammad Mamdani agreed the technique has real merits for some -- though not all -- medications.

"Yes, it's absolutely wonderful if you're looking at drugs where you don't need the exact, exact, exact dose - where you can be off by a little bit and it's fine," said Mamdani, director of the Applied Health Research Centre of the Li Ka Shing Knowledge Institute at St. Michael's Hospital in Toronto.

He suggested the technique would not be advisable for antipsychotic drugs.

And Mamdani, who worked for a time in the pharmaceutical industry, warned drug makers are watching this issue and may adjust prices upward if profits start to tumble because pill splitting becomes more popular.

"Absolutely, industry knows about this and they're definitely thinking 'OK, what do we do about it?"' he said.

"If there's a huge market shift towards pill splitting, I bet you there's going to be a response from industry."