When a drug is touted as a potential cancer-fighter, beware the side effects

Blinders firmly in place

Once again, drug researchers are trying to get you to play “Let’s Pretend.”

In this case, they’re hoping to convince you that a drug used by type 2 diabetics might help prevent cancer — even in non-diabetics.

Now, all of that might eventually prove true, but here’s where they want you to ignore reality and use your imagination: Let’s pretend there’s no downside to this plan.

Don’t say hello to my large gray friend

Most cancer drug researchers have to wear blinders so they won’t catch a glimpse of that inconvenient elephant in the room: patient safety.

With blinders firmly in place, South Korean researchers investigated research that suggests the type 2 diabetes drug metformin may reduce breast cancer risk, as well as other diabetes-related cancers.

In a laboratory trial, metformin reduced the number and size of breast tumors, apparently disrupting the harmful effects of carcinogenic chemicals and estrogen.

Okay, this is the ground floor of research — getting a look in the lab at how things might go in the body.

But one of the researchers wasn’t content with ground floor success. He was already wondering what the view might be like from the penthouse. In a press release he speculated that metformin might be used as cancer prevention in “individuals who have no indication of any existing cancers.”

Wow. That’s bold. Based on a lab study, he’s already imagining metformin for every man, woman, and child. But why stop there? Why not put it in the water supply — a bonus for diabetics and everyone else who wants to lower cancer risk?

Here’s the number-one reason to keep it out of the water: That “patient safety” elephant is still in the room. Yes, even up there in the penthouse.

As with any drug, metformin has side effects. In fact, when you search online, you’ll find side effects listed on websites such as metformin-sideeffects.com, metforminsideeffectsinfo.org, and themetforminsideeffects.net. That’s three separate websites devoted entirely to…well, you get the idea.

Compared to many drugs, metformin’s side effects are relatively mild — unless, of course, you have to endure two or three of them at the same time.

Here are a few of the key adverse effects that appear on all three sites…

* Difficulty breathing
* Heart palpitations
* Dizziness
* Flu-like symptoms (weakness, fever, chills)
* Excessive sweating
* Muscle aches

And although metformin is taken to control blood sugar, side effects may include high blood sugar or low blood sugar.

That’s kind of a substantial elephant to ignore — especially when you consider a newly discovered metformin side effect I told you about in 2010: vitamin B12 deficiency.

A four-year study in the Netherlands confirmed reduced B12 absorbency in diabetic patients who used metformin. Some subjects were at high risk of developing full-blown deficiency of this very important vitamin that helps keep homocysteine levels low. And as I’ve mentioned many times, high homocysteine increases risk of dementia, heart attack, and stroke.

Whether you’re a type 2 diabetic or in perfect health, you do not want to compromise your B12 status. Not even in return for a small cancer prevention benefit. Any elephant can tell you that.

Sources: 
“Metformin Represses Self-Renewal of the Human Breast Carcinoma Stem Cells via Inhibition of Estrogen Receptor-Mediated OCT4 Expression” PLoS ONE, Vol. 6, No. 11, 11/23/11, plosone.org

“Diabetes drug shows promise in reducing risk of cancer” Michigan State University press release, 11/23/11, eurekalert.org

“Long term treatment with metformin in patients with type 2 diabetes and risk of vitamin B-12 deficiency: randomised placebo controlled trial” BMJ, Published online ahead of print 5/20/10, bmj.com