Yes, several prescription medications are available for constipation, and they work through different mechanisms than the over-the-counter options you may have already tried. Doctors typically prescribe them when fiber supplements, stool softeners, and osmotic laxatives like polyethylene glycol (MiraLAX) haven’t provided enough relief. The main prescription categories include drugs that pull fluid into your intestines, drugs that speed up your colon’s contractions, and a specialized class for people whose constipation is caused by opioid pain medication.
When Doctors Move Beyond OTC Options
Clinical guidelines from the American Gastroenterological Association and American College of Gastroenterology lay out a clear stepwise approach. For chronic constipation, polyethylene glycol (PEG) gets a strong recommendation as a first-line treatment, with fiber supplements as a conditional option. Prescription medications enter the picture when these over-the-counter approaches fail. In practice, this means you’ve consistently used an osmotic laxative or fiber for several weeks without adequate improvement in how often you go, how hard you strain, or how complete your bowel movements feel.
There’s no single bowel movement number that automatically triggers a prescription. But chronic idiopathic constipation, the formal diagnosis these drugs treat, generally means fewer than three spontaneous bowel movements per week along with symptoms like straining, hard stools, or a sense of incomplete evacuation persisting for at least three months.
Secretagogues: Pulling Fluid Into the Gut
The largest group of prescription constipation drugs are called secretagogues. They work by triggering cells lining your intestines to release more fluid into the gut, which softens stool and helps it move through more easily. Three are currently available.
Linaclotide (Linzess) activates a receptor on the intestinal surface that increases fluid secretion. It’s approved for both chronic idiopathic constipation and irritable bowel syndrome with constipation (IBS-C), with doses of 145 mcg once daily for constipation and 290 mcg for IBS-C. It’s barely absorbed into the bloodstream, so it acts almost entirely within the gut. Among the prescription options, linaclotide received the strongest endorsement from gastroenterology guidelines, with moderate-certainty evidence supporting its use. It’s also the first prescription constipation drug approved for children, specifically for kids 7 and older with IBS-C. Children under 2 should not take it due to a risk of serious dehydration.
Plecanatide (Trulance) works through the same receptor as linaclotide and is approved for both chronic constipation and IBS-C in adults 18 and older. The dose is simpler: 3 mg once daily for either condition. Like linaclotide, it also carries strong guideline support. The FDA has issued a boxed warning to avoid plecanatide in children 6 and younger because of the potential for dangerous dehydration.
Lubiprostone (Amitiza) takes a different route, activating chloride channels on intestinal cells to drive fluid secretion. It’s approved for chronic constipation and IBS-C, though its guideline recommendation is conditional rather than strong, reflecting lower-certainty evidence. The most notable side effect is nausea, which affects up to 29% of patients in clinical trials. Diarrhea occurs in about 12%. Lubiprostone is contraindicated if you have a bowel obstruction or severe liver disease.
Prokinetics: Speeding Up the Colon
While secretagogues add fluid, prokinetics take a different approach by making the colon contract more forcefully. Prucalopride (Motegrity) is a selective serotonin type 4 receptor agonist, meaning it activates specific receptors in the gut wall that trigger high-amplitude contractions. These are the powerful, wave-like squeezes that push stool from the beginning of the colon all the way to the rectum. It’s approved for chronic idiopathic constipation in adults who haven’t responded well to other laxatives.
Prucalopride is contraindicated in people with bowel obstruction or perforation, inflammatory bowel diseases like ulcerative colitis or Crohn’s disease, and toxic megacolon. Because it’s highly selective for one type of serotonin receptor, it avoids many of the cardiac side effects that plagued earlier drugs in this category.
PAMORAs: For Opioid-Caused Constipation
If your constipation is caused by opioid pain medications, standard laxatives often fall short because the problem isn’t a lack of fiber or fluid. Opioids bind to receptors throughout your digestive tract, slowing gut movement and increasing water absorption from stool. Peripherally acting mu-opioid receptor antagonists (PAMORAs) were designed specifically for this situation. They block the opioid’s effect on your intestines without crossing into the brain, so they relieve constipation without reducing pain relief.
Three PAMORAs are available: methylnaltrexone (available as an injection or oral tablet), naloxegol (oral), and naldemedine (oral). Each is taken alongside your existing opioid regimen. The key engineering behind these drugs is that their molecular structure prevents them from passing through the blood-brain barrier. Methylnaltrexone achieves this through a chemical modification that makes the molecule more polarized and less fat-soluble. Naloxegol uses a different strategy, attaching a polymer chain to naloxone that keeps it locked out of the central nervous system.
What to Expect From Prescription Treatment
Most prescription constipation medications are taken once daily, typically on an empty stomach or before the first meal. Improvement usually begins within the first week, though it can take longer for some people to reach full benefit. Diarrhea is the most common side effect across nearly all of these drugs, which makes sense given that they work by increasing fluid in the gut or accelerating transit. Your doctor may adjust the dose if stools become too loose.
These medications are generally intended for ongoing use rather than short courses. Chronic constipation tends to return when treatment stops, so many people stay on their prescription long term. Cost can be a factor, as brand-name secretagogues and prokinetics are significantly more expensive than OTC laxatives. Insurance coverage varies, and some plans require documentation that you’ve tried cheaper options first, a process called step therapy or prior authorization.
If you’ve been managing constipation with over-the-counter products for weeks or months without real improvement, a prescription option may offer a different mechanism your body responds to better. The choice between a secretagogue, a prokinetic, or a PAMORA depends largely on what’s causing your constipation and which symptoms bother you most.