QUESTION:  I will soon be having a colonoscopy. I had one ten years ago. My doctor recommended the test to check for colon cancer. Now he says it’s time to do it again. I didn’t mind the procedure. But I hated drinking that horrible fluid beforehand to clean out my bowel. Why does that stuff taste so awful and is there an alternative?

ANSWER: Been there. Done that. And I know your pain.

Almost everyone who has had a colonoscopy – myself included – complains about the preparation.

The colonoscopy itself – in which a viewing scope is inserted in the rectum – isn’t all that bad.  Most patients are sedated when that’s happening.

But there is no avoiding the dreaded prep. The colon needs to be as clean as a whistle before the doctor can insert the 5-to-6-foot long flexible scope into the colon.

So you will need to purge your intestines.  The standard preparation is sold under several different brand names including Peglyte, GoLytely, Colyte and Klean-Prep.

The kits usually consist of a container with a powdered mixture, to which you add four litres of water to form the solution. You then drink the concoction over a period of several hours on the day before your colonoscopy.

“The idea behind the preparation is that the large volume of fluid essentially washes out and cleanses the colon,” explains Dr. Michael Bernstein, a gastroenterologist at Sunnybrook Health Sciences Centre.

“It is not a pleasant experience,” acknowledges Annie Hui, a Sunnybrook pharmacist. “You will need to be at home where you have ready access to a bathroom.  You are going to have watery bowel movements for hours – by the end of the prep, the rectal discharge will be clear fluid. Everything has been flushed out.”

Indeed, it’s a like a great whoosh going through your gastrointestinal passageway.

Drinking four litres of fluid would be a challenge by itself.  However, it’s the powdered mixture that provides the added burden of the awful taste.

One of the substances in the mixture is polyethylene glycol, which is sometimes used in small doses to treat constipation. It works by drawing water into the colon, which softens the stool and stimulates the movement of the muscles lining the colon, producing bowel movements.

The vile taste arises from the second key component of the mixture – electrolytes such as sodium and potassium, which are minerals that normally circulate in the blood and help regulate everything from nerve conduction to heart function.

“The body loses lots of fluid and electrolytes during the bowel prep process,” says Dr. Hui. For that reason, the mixture contains lots and lots of electrolytes to make sure the body’s supply of these minerals remain in balance.  They are basically salts. So the concoction includes heavy-duty sweet flavouring to mask the predominately salty taste.

Most people find it barely palatable.

For those who just can’t get it all down the hatch, there are a few “low-volume” alternatives. Pico-Salax and a similar product called Purg-Odan are among the most commonly used brands.

Pico-Salax contains three ingredients – picosulfate sodium, magnesium oxide and citric acid – which act as a laxative, stimulating muscles in the colon to contract while also drawing water into the colon.

With this product, you add a packet of the mix to a 150-millilitre glass of water and drink it down. It doesn’t taste very nice. Then about six or more hours later – depending on the timing of your colonoscopy – you add another packet to a glass of water and gulp down the wretched drink. (Many physicians will also prescribe a stimulant laxative on the day before the prep in order to “jump-start” the process.)

You still have to consume lots of additional fluid to flush out your colon, but you can use almost any clear liquid you like – such as water, juice or Gatorade (But no red, purple or blue-coloured drinks which can stain the colon and lead to misleading test results.)

Overall, you’re drinking only two glasses of awful-tasting stuff rather than four full litres.

“The upside is that this approach is much more attractive to patients in terms of how much [bad-tasting fluid] they have to get through,” says Dr. Bernstein.

“The downside is that it doesn’t tend to be quite as good at cleaning out the colon.”

The laxative can also cause cramps. As well, there is a risk that the patient’s electrolytes may get tipped out of balance.  So, this approach should be used only by those who are in generally good health. “People with bad kidney disease or heart disease should not use low-volume preparation,” says Dr. Bernstein.

He usually recommends that his patients stick to the high-volume colon preparations “because I think they are more consistently successful. ”

Still, if you would prefer a low-volume option, consult with your doctor – don’t just select one on your own. (Some contain a combination of laxatives and electrolytes.)

If it fails to do a thorough job, the examination of the lining of the colon could be obscured by residual stool. You may need to have another colonoscopy and go through the whole procedure again.

“Most doctors – or colonoscopy clinics – have very specific instruction sheets they give their patients and they don’t necessarily want their patients to deviate from those instructions, ” says Dr. Hui. “If you want an alternative, the doctors will let you know the one to use.”

Aside from which preparation you select, there are a few other things you can do to reduce the discomfort:

• Refrigerating the liquid will make it go down more easily.  It should be consumed within 24 hours of mixing the solution.
• Drink each glass rapidly. “If you sip it, you’re never going to finish,” says Dr.Hui. “Just chug it.”
• Modify your diet in the days leading up to your colonoscopy prep.  Avoid small nuts, seeds, and grains.  They can get caught in the folds and crevices of the colon and may not be properly digested.
• You probably want to “stay away from spicy foods, too,” says Christina Mychaskiw, a pharmacy intern at Sunnybrook.
• Diaper-rash ointment or a similar salve may help prevent your anus from becoming raw and irritated.

At this point, you might be asking yourself:  Is all the misery really worth it? The short answer is YES!  A colonoscopy, if done at the right time, can actually prevent the development of cancer.

Colon cancer usually begins with abnormal growths called polyps, explains Dr. Bernstein. By using the viewing scope, the doctor can look for these growths inside the walls of the colon. Devices such as forceps, or a snare, can be threaded through a channel in the scope in order to remove any polyps that are found. That means the procedure is stopping a potential cancer before it has a chance to develop and spread.

Of course, there are less invasive tests that are also used to screen for colon cancer.  One is known as the Fecal Occult Blood Test. You collect small samples of your stool on a card and send them to a lab that looks for the presence of blood.  However, by the time blood is evident in the stool a polyp may be well on the way to becoming cancerous. By contrast, a colonoscopy can literally nip a precancerous growth in the bud.

So, while you’re trying to drink down your colonoscopy prep, consider these statistics from the Canadian Cancer Society:

• About 24,300 new cases of colorectal (colon and rectum) cancer are diagnosed each year in Canada and 9,300 people die from the disease.
• Colorectal cancer is the third most commonly diagnosed cancer in Canada (excluding non-melanoma skin cancers).
• It is the second leading cause of death from cancer in men and the third leading cause of death from cancer in women in Canada.

Many of these cases could be avoided with a well-timed screening colonoscopy.