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DEAR DR. ROACH: I’m a healthy, active 69-year-old female. I’ve had problems with constipation for several years,and it’s recently worsened. When I had my first colonoscopy, the doctor at the time, who’d been doing colonoscopies for 50 years, told me that I had the longest colon he’d ever seen.
When I had my second (and most recent) colonoscopy, which was postponed for two days because I needed a stronger laxative to clear my colon, he told me my colon was so convoluted that I probably shouldn’t have another colonoscopy.
Over the past few months, I have gone for up to three weeks without a bowel movement. I saw a physician assistant who ordered an X-ray that showed a completely full colon without a blockage. He told me to take 7 capfuls of MiraLAX daily for a week, which I did without results. So, he prescribed Linzess — again, without results.
Then he told me to take both MiraLAX and Linzess daily, which provided a slight but inadequate relief. I then saw a gastroenterologist at another practice who prescribed GoLYTELY to clear my colon, then Ibsrela twice daily, which resulted in extreme cramping and constant diarrhea.
Afterward, I remained on Ibsrela only, and 1 dose daily resulted in 7-10 bowel movements daily. But 1 dose every other day resulted in constipation, so he changed me to lubiprostone twice daily. Now, after seven days of lubiprostone twice daily, I haven’t had any bowel movements. I’d greatly appreciate any insights and suggestions you can offer me. -- S.L.
ANSWER: You have an unfortunate situation of severe constipation that you haven’t found relief for. All the steps that have been taken so far are pretty reasonable (although I haven’t heard anything about your diet and any medications that might be slowing down your colon). There are also some medical issues that should be considered, such as low thyroid levels, which might be worsening your tendency to get constipated based on your colon anatomy.
Polyethylene glycol (MiraLAX and GoLYTELY are both polyethylene glycol but different sizes of the molecule) isn’t absorbed into the body, so it goes right through you, bringing fluid along with it. These are very effective treatments for most people.
Linaclotide (Linzess) activates an ion channel in the intestine, causing the movement of chloride and bicarbonate ions into the intestine. This also brings more water into the intestine, causing a softer stool. Tenapanor (Ibsrela) acts similarly, but instead blocks a sodium channel so that your gut can’t absorb sodium. This keeps more water in the colon and creates a softer stool. Finally, libiprostone acts on yet another ion channel — this time blocking chloride channels that results in chloride, sodium and water going into the bowel.
The frustrating part is that Ibsrela was the most effective drug for you. It was toxic at one dose, causing too many bowel movements. Then, when taken every other day, it was ineffective. There’s no in-between dose to be given with this medicine, and although you could try taking it every 36 hours, this drug is well-known to have a very narrow dose of effectiveness.
Your options at this point include higher doses of Linzess or lubiprostone, more MiraLAX, or a completely different class of drug such as prucalopride, which works by stimulating the gut to move more strongly. A gastroenterologist with special expertise in irritable bowel syndrome is an ideal consultant.
Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu. (c) 2026 North America Syndicate Inc.
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