VANCOUVER - Men who suffered ongoing erectile dysfunction after taking prescription drugs to treat prostate problems and male pattern baldness will be able to pursue a class-action lawsuit against the drug maker, a B.C. judge has ruled.

The lawsuit was brought by Michael Miller against Merck Frosst Canada, makers of Propecia and Proscar, two drugs that contain the medication finasteride.

Miller was 25 in 2008, when he said he obtained a prescription for Proscar from his doctor, according to a written court ruling.

Although that drug is for the treatment of prostate problems, it contains the same medication as Propecia, used to treat male pattern baldness.

Miller said he was advised to cut the five milligram tablet into four, making it roughly the same as the more expensive one-milligram Propecia tablets.

"Approximately one month after using Proscar the plaintiff alleges he experienced a diminished sex drive," said the March 28 written decision by B.C. Supreme Court Justice Robert Punnett posted Tuesday on the court website.

"Over the ensuing months, he became completely disinterested in sexual activity and was unable to maintain an erection."

Miller came across a website where other men linked sexual dysfunction to the drugs months after they had stopped taking them, and he discontinued use at the end of January 2009, "expecting that these alleged side effects would disappear."

They did not, the lawsuit claims, and Miller launched the class-action.

"The plaintiff asserts that the defendants were aware of the long-term side effects and that the warnings given in Canada were inadequate," the judge noted in his ruling.

In Sweden, for example, officials asked Merck six years ago to include in the warning the possibility of persistent erectile dysfunction continuing after use discontinued, and Merck agreed in 2008 to do so.

While the warning labels in Canada for both products did note that "so-called side effects," which were "uncommon and do not effect most men," may include impotence, problems with ejaculation and decreased semen, they were not enough, Miller claimed.

Punnett ruled that the class-action lawsuit is appropriate, but certification is pending. The judge asked Miller's lawyers to provide an affidavit with information on potential litigants and asked both parties to provide information on expert reports they plan to submit.

Merck has argued in this case and others that the plaintiffs have not provided scientific or medical evidence proving a link between the medication and the condition.

Neither a company spokesperson nor David Lyons, Miller's lawyer, were available for comment Tuesday.

Miller's lawyers told the judge they have been contacted by almost 300 men — 55 of them from B.C. — who want to join the lawsuit.

A similar lawsuit was filed in 2011 in Ontario Superior Court by Sean Ramsaran and Chris Asimakopoulos.

In its third quarter earnings report last November, Merck & Co. announced it had been named in 265 lawsuits in New York and New Jersey alone over the sexual side effects of Propecia.

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  • Arginine

    Nitric oxide is a key component in developing and maintaining an erection. <a href="">The amino acid L-arginine</a> -- found naturally in red meat, fish and wheat germ among other foods -- is known to boost the body's production of nitric oxide and has been used to successful treat ED in the past, according to WebMD. The Natural Medicines Comprehensive Database has also said the <a href="">amino acid could be used to treat ED</a>, Everyday Health reports.

  • Spider Venom

    The toxin PnTx2-6 -- found in the <a href="">venom of the Brazilian wandering spider</a> -- was found to improve "erectile function in aged rats," according to a study published in August.

  • Pomegranate Juice

    Pomegranate juice has a number of health benefits; researchers recently found the tart drink was responsible for l<a href="">owering blood pressure</a>. A 2007 small-scale study that found promising results in using <a href="">pomegranate juice to protect against ED</a> called for a larger test to prove its efficacy, WebMD reports.

  • Yohimbe

    Mmm, bark. Prior to Viagra hitting the market, doctors would prescribe the bark of the African yohimbe tree to ED sufferers. While its ability to improve erections is questioned, doctors are no stranger to its <a href="">yohimbe's many scary side effects</a>, including increased blood pressure and irregular heart beat, according to WebMD.

  • Ginseng

    Live Science noted that ginseng was among one of the many <a href="">natural aphrodisiacs</a> that had the most potential to treat ED.

  • Gingko

    A recent study found that <a href="">ginko biloba extract does not prevent memory loss in those with Alzheimer's</a>, but it may help ED sufferers by increasing <a href="">blood flow to the penis</a>, according to Mayo Clinic.

  • Epimedium

    Also known by its snicker-inducing name horny goat weed, <a href="">epimedium has traditionally been used in Chinese medicine to treat ED</a>, according to the Mayo Clinic. However it warns that there has been little study into the herb's side effects, which include blood thinning and lower blood pressure.

  • Zinc

    For men with zinc deficiency, taking <a href="">the mineral may help with erectile dysfunction</a>, according to Mayo Clinic.

  • Acupuncture

    A recent survey of four studies found there wasn't enough evidence to prove that using the centuries-old practice to treat ED actually worked. But urologist Bruce Gilbert told Everyday Health acupuncture is worth a shot: "It probably works best to treat the psychological component of ED. There is very little downside to trying it."