Colonoscopy Prep on the Cheap

Early detection can significantly reduce deaths from colorectal cancer. More good news: Our reporter figured out how to prep for his screening without spending $85 on a laxative.

Consumer Reports Marketplace Equity Reporter, Brian Vines.

By Brian Vines
Marketplace Equity Reporter

May 28, 2025

Brian Vines drinking liquid in preparation for his colonoscopy and in a hospital gown.

One thing about me: I’m gonna ask for a discount.

While I won’t haggle with local, independent vendors who are putting in the work on their entrepreneurial dreams, I have no qualms about big deals at big box and department stores and discount chains. At such places, in the spirit of “you have not because you ask not,” I routinely lobby for a “good guy discount.”

Recently at the CVS, when presented with the prospect of an $85 copay for Plenvu, a laxative prescribed by my gastroenterologist ahead of an upcoming colonoscopy, I balked. Why, I asked the pharmacist, was the copay for a laxative more expensive than what I was spending on the colonoscopy itself? He informed me that “some of these medications cost thousands of dollars.”

No doubt that’s true. But $85 for a laxative? I couldn’t stomach flushing that much down the drain for something that spicy food and a large iced coffee seemed able to accomplish for a fraction of the price.

A truce was struck when the pharmacist realized the store did not have Plenvu in stock. Leaving the pharmacy equal parts outraged and determined, I made it my mission to get a discount on that “medicine.”

Manufactured by Salix Pharmaceuticals, Plenvu is a commonly recommended laxative for bowel prep ahead of a colonoscopy. It comes as a powder divided into three packets. The night before the procedure, you dissolve the first in cold water and drink the resulting sludge and then 16 ounces of a clear liquid. The other two packets get mixed with 16 ounces of water the morning of—but at least 2 hours before—the procedure, followed by another 16-ounce clear-liquid chaser.

When I was preparing for my colonoscopy in May, the retail price of Plenvu on the prescription drug price tracking and discount site GoodRx, without insurance, ranged from $151 at Wegmans to $169 at Target/CVS. At Amazon Pharmacy, the retail price without insurance was $155.58, or $147.44 (5 percent off) if you’re an Amazon Prime member.

Those prices could lead a normal person to believe an $85 copay is a pretty good deal. But this cost-conscious consumer couldn’t help thinking about how much of my paycheck already goes to a health insurance plan that includes a prescription drug plan. In that context, a 50 percent “discount” just didn’t sit well.

My first attempt to prep for less was an internet search for a manufacturer’s coupon. I was not disappointed. When I saw the “Savings and Resources” tab on the Plenvu website I knew I was on the right track. In addition to a Medicare Part D coupon program for out-of-pocket costs exceeding $60, there was a Plenvu Co-pay Assistance Card. A few clicks later and that card, with its offer for commercially insured patients with or without coverage for Plenvu to pay as little as $55, was on its way to my printer.

A few days ahead of my procedure, a nurse from the endoscopy center phoned to verify my insurance info and answer any questions I might have. Before finishing the call I told her the $85 copay for a laxative had me taken aback, and she replied, “Oh, you can go the OTC route.” Excuse me, over the counter?

Two minutes after we hung up, a text link with instructions for the Miralax prep arrived on my phone. Miralax is a brand-name, over-the-counter version of polyethylene glycol 3350 (PEG), a polymer-based laxative that increases the amount of water your intestine absorbs, making stool softer and easier to pass. When combined with over-the-counter laxative tablets bisacodyl (widely available under the brand name Dulcolax) you get a one-two punch that will have your insides endoscope-ready in under 24 hours.

Apple juice, Amazon-branded ClearLax laxative, and Snapple peach flavored iced tea. — A recipe for savings: ClearLax and apple juice.

I was skeptical at first: A friend of mine recently spent a day choking down an entire container of goopy prep liquid that made them gag, only to have their colonoscopy aborted because their colon wasn’t clear enough to proceed. I’d already cut the price of my prep in half. Was additional savings worth the risk?

The savings can actually be significant. Both products are widely available in stores as well as online, which is where I got them. Walgreens brand bisacodyl costs $3.99 for 10 tablets, and ClearLax, the Amazon Basic Care version of MiraLax, is $7.66 for 8.3 ounces. Grand total: $11.65—a $73.35 savings off the original quote.

In the end, my desire to save money outweighed my concerns. So at 4 p.m. the day before my colonoscopy, I downed two bisacodyl tablets with 8 ounces of water and 32 ounces of ClearLax-laced clear liquid—I chose apple juice—followed by more of the same at 10 p.m. The hour I spent in the restroom was proof positive that this OTC method was valid. My doctor second-opinioned that after my procedure the next morning.

“It’s not about one option being universally better, but rather about tailoring the choice to the patient’s health status, anatomy, and likelihood of adherence,” says Ugonna Iroku, MD, an assistant clinical professor at Mount Sinai Hospital in New York City and the gastroenterologist who performed my colonoscopy. “Ultimately, the best prep is the one a person has access to and will take.”

Colorectal screening saves lives—and if you can save money while doing it, it’s even better.

Brian Vines

Brian Vines has been a member of the special projects team at Consumer Reports since 2020, focusing on marketplace inequities. Prior to joining CR, he spent a decade covering public affairs in community media. A Chicago native, he has a passion for social justice and deal hunting. Follow him on X: @bvines78.