Constipation and IBS: medications and paying cash

Overview

Constipation means fewer than three bowel movements a week, or stools that are hard, dry or difficult to pass; chronic idiopathic constipation is the long-lasting kind with no known cause. Irritable bowel syndrome (IBS) causes abdominal pain or cramps, bloating and gas along with a change in bowel habits, and is grouped by the main pattern: IBS with constipation (IBS-C), IBS with diarrhea (IBS-D), or mixed. Blood in the stool and weight loss you cannot explain are not part of IBS, and they, like bowel symptoms that begin at age 50 or older, need a doctor’s evaluation.

For constipation, the first steps are more fiber from food or a supplement, with plenty of fluid, regular physical activity, and not putting off the urge to go. Over-the-counter options include fiber supplements, osmotic laxatives such as polyethylene glycol 3350 (MiraLAX), stool softeners and stimulant laxatives; laxatives are for short-term use, as a health professional advises, and stimulant laxatives only when constipation is severe or other treatments have not worked. The MiraLAX label limits self-treatment to seven days and asks people with IBS to check with a doctor first.

Linaclotide, plecanatide and lubiprostone treat chronic idiopathic constipation and IBS-C, and tenapanor treats IBS-C; all increase fluid in the bowel, diarrhea is a common side effect, and lubiprostone often causes nausea. Linaclotide’s boxed warning says it must not be given to children under 2 because of the risk of serious dehydration, though it is approved for functional constipation from age 2 and IBS-C from age 7; plecanatide is contraindicated under 6 and avoided until 18, and tenapanor has a similar warning. Lubiprostone is labeled for IBS-C only in women 18 and older. For IBS-D, rifaximin is a 14-day antibiotic course that can be repeated up to two times if symptoms return, and eluxadoline, a Schedule IV controlled substance, is not used by people without a gallbladder, with past pancreatitis, or who drink more than three alcoholic drinks a day. Alosetron is limited to women with severe IBS-D that has not responded to conventional treatment. It was withdrawn by its maker in 2000 after cases of ischemic colitis and serious complications of constipation and returned in 2002 under a restricted program that later became a REMS; the FDA ended the REMS in 2023, but the boxed warning remains. The antispasmodics dicyclomine and hyoscyamine ease cramping but can cause dry mouth, blurred vision, drowsiness and overheating in hot weather.

Choosing between the options when you pay cash

Fiber supplements and polyethylene glycol 3350 are sold over the counter. Lactulose, lubiprostone and dicyclomine are generics, and quotes for the same quantity can differ between pharmacies; once a dose is settled, a ninety-day supply means fewer fills. Linaclotide, plecanatide and tenapanor are sold only as Linzess, Trulance and Ibsrela, so a pharmacy has nothing to substitute; for chronic idiopathic constipation, or for IBS-C in a woman, ask the prescriber whether generic lubiprostone would suit you.

For IBS-D, alosetron is sold as a generic from several makers, while eluxadoline is sold as Viberzi and, as a controlled substance, has limits on refills. Hyoscyamine is marketed without FDA approval, so no maker’s product is rated equivalent to another’s, while dicyclomine is FDA-approved for IBS. Which medicine fits depends on the bowel pattern, age, sex and other conditions, so a switch from one to another is the prescriber’s decision, not the pharmacy’s.

Medicines at a glance

How the medicines in this group are supplied and usually taken. Each guide has the full details.

• Linaclotide
  Capsules
  Generic: No · Once a day
• Lubiprostone
  Capsules
  Generic: Yes · Twice a day
• Plecanatide
  Tablets
  Generic: No · Once a day
• Lactulose
  Oral solution, Packets of crystals for oral solution
  Generic: Yes · Once a day
• Dicyclomine
  Capsules, Tablets, Oral solution
  Generic: Yes · Four times a day
• Hyoscyamine
  Tablets, Sublingual tablets, Orally disintegrating tablets
  Generic: No · See the guide

Medications

Which of these is right for a given person is a decision for the prescriber. The guides explain what each drug is, how it is supplied, and why its cash price varies between pharmacies. No page on this site shows a price; prices come from pharmacies responding to your actual prescription.

Questions worth asking

• Is this chronic constipation or IBS with constipation, and does that change which medicine fits?
• How long should I try fiber or polyethylene glycol before a prescription medicine?
• Would generic lubiprostone or lactulose suit me instead of a brand-only medicine?
• What should I do if I get severe diarrhea, dizziness or signs of dehydration?
• How should I store these medicines so that young children cannot get to them?

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