Opioid-Induced Constipation Score Calculator
The Bowel Function Index (BFI) is a simple tool used to measure constipation severity in patients taking opioids. It helps determine if your treatment is effective or needs adjustment.
How difficult was it to have a bowel movement?
How often did you feel like you didn't completely empty your bowels?
How often did you feel bloated or uncomfortable?
Select one option for each question. Click the 'Calculate Score' button to see your results.
Your BFI Score
Why Opioid-Induced Constipation Is So Common - And Why It Doesn’t Go Away
When you start taking opioids for chronic pain, you’re not just getting pain relief. You’re also setting off a chain reaction in your gut that can turn everyday life into a constant struggle. Opioid-induced constipation affects 40 to 60% of people on long-term opioid therapy, even if they’ve never had bowel issues before. Unlike side effects like drowsiness or nausea, which often fade after a few weeks, constipation sticks around. And it doesn’t get better on its own.
This isn’t just about needing to go less often. Opioids bind to receptors in the walls of your intestines, slowing down the natural muscle contractions that push food and waste along. The result? Stool moves slower, water gets sucked out, and your colon becomes sluggish. Your anal sphincter tightens up, too, making it harder to fully empty your bowels. Many patients describe it as straining, feeling incomplete after a bowel movement, or bloating so badly they look pregnant.
Even if your opioid dose hasn’t changed, constipation can get worse over time. And if you ignore it, it can lead to nausea, vomiting, abdominal pain, or worse - fecal impaction, where hardened stool blocks your intestine entirely. That’s not just uncomfortable. It’s dangerous.
Start Laxatives the Same Day You Start Opioids
The biggest mistake doctors and patients make? Waiting for constipation to happen before treating it. By then, it’s already entrenched. Experts agree: if you’re starting opioids, you should start a laxative the same day. Proactive treatment cuts the risk of severe constipation by 60 to 70%.
Not all laxatives are created equal. Over-the-counter options like senna or bisacodyl (stimulant laxatives) help trigger contractions, but they don’t fix the root problem. Stool softeners like docusate? Often ineffective for OIC. The most reliable first-line choices are osmotic laxatives - especially polyethylene glycol (PEG), sold as Miralax. PEG draws water into the colon naturally, softening stool without irritating the gut. It’s safe for daily use, doesn’t cause dependency, and works better than anything else for opioid-related constipation.
Start with one capful of Miralax daily. If you’re not having a bowel movement every 2 to 3 days after a week, increase to two capfuls. Keep track. Don’t wait until you’re in pain to adjust the dose. This isn’t a one-size-fits-all fix. Some people need 2 to 3 capfuls. Others need more. Your body tells you what it needs.
When Laxatives Don’t Work - What Comes Next
For nearly 70% of patients, standard laxatives just aren’t enough. That’s not your fault. It’s because OIC works differently than regular constipation. Your gut isn’t just slow - it’s being actively suppressed by the opioid. That’s where PAMORAs come in.
PAMORAs - peripherally acting μ-opioid receptor antagonists - are the only class of drugs designed specifically to reverse opioid effects in the gut without touching pain relief in the brain. They block the receptors in your intestines but can’t cross the blood-brain barrier. So you still get pain control, but your bowels start moving again.
Three FDA-approved PAMORAs are currently available:
- Naldemedine (Symproic®): Taken as a daily pill. Proven to improve bowel function and even reduce opioid-related nausea. Recommended by ASCO for cancer patients starting opioids.
- Methylnaltrexone (Relistor®): Available as a daily injection or now a once-weekly shot. Works fast - often within 30 minutes. Popular among patients in palliative care.
- Naloxegol (Movantik®): Daily oral tablet. Works well for many, but can cause stomach cramps in about 28% of users.
These aren’t magic bullets. Some people still don’t respond. Others get abdominal pain, diarrhea, or gas. But for many, they’re life-changing. One patient on Reddit wrote: “Relistor saved me. I hadn’t had a real bowel movement in 11 days. One shot - and I was fine within an hour.”
The Hidden Risks and Who Should Avoid PAMORAs
These drugs are powerful, but they’re not safe for everyone. The FDA requires a black box warning because PAMORAs can cause serious gastrointestinal perforation - a tear in the bowel wall. That’s rare, but it’s real. It’s more likely if you’ve had recent abdominal surgery, inflammatory bowel disease, or a history of bowel obstructions.
Doctors need to screen for these red flags before prescribing. If you’ve had a bowel obstruction in the past, or if you’re on blood thinners and have unexplained abdominal pain, PAMORAs might not be right for you. Always tell your provider about any past surgeries or gut conditions.
Also, these drugs cost a lot. Without insurance, a month’s supply can run $500 to $900. Many insurance plans require prior authorization or force you to try cheaper laxatives first - even though they often don’t work. That delay can mean weeks of suffering. Some patients give up after 6 months because of cost or side effects. That’s why advocacy groups are pushing for better coverage - untreated OIC costs the U.S. healthcare system over $2 billion a year in ER visits and hospitalizations.
What You Can Do Right Now - Even Without a Prescription
Medication isn’t the only tool. Lifestyle changes matter - a lot. But they’re not replacements. They’re support.
- Drink more water: Aim for at least 2 liters a day. Dehydration makes constipation worse, and opioids already pull water out of your stool.
- Move your body: Even a 20-minute walk daily helps stimulate gut motility. Sitting all day? That’s the opposite of what your colon needs.
- Eat fiber - but carefully: Too much fiber without enough water can make things worse. Focus on soluble fiber - oats, apples, psyllium husk - not just bran. Add it slowly.
- Don’t ignore the urge: If you feel the need to go, go. Delaying makes stool harder and the reflex weaker over time.
And don’t rely on enemas or suppositories long-term. They’re good for emergencies, not daily management. Overuse can damage your rectum and make you dependent.
How to Know If Your Treatment Is Working
How do you know if your laxative or PAMORA is actually helping? Don’t guess. Use a simple tool called the Bowel Function Index (BFI). It’s a three-question survey doctors use to measure constipation severity:
- How difficult was it to have a bowel movement? (1 = easy, 4 = very difficult)
- How often did you feel like you didn’t completely empty your bowels? (1 = never, 4 = always)
- How often did you feel bloated or uncomfortable? (1 = never, 4 = always)
Add up the scores. Below 30? You’re doing okay. Above 30? Your treatment needs adjusting. Many patients don’t realize they’re still constipated because they’ve gotten used to feeling bad. That’s why tracking matters.
Keep a log: date, bowel movement, stool consistency (use the Bristol Stool Scale), meds taken, and symptoms. Bring it to your next appointment. It tells your doctor more than any description ever could.
What’s Coming Next - And Why There’s Hope
The future of OIC treatment is getting better. In 2023, the FDA approved a once-weekly version of methylnaltrexone. That’s a game-changer for people tired of daily injections. Researchers are also testing oral PAMORAs with better absorption and combo pills that pair low-dose PAMORAs with gentle laxatives - one pill to do both jobs.
Even more exciting? Personalized medicine. By 2026, doctors may use genetic tests to predict who responds best to which drug. Some people metabolize PAMORAs faster. Others have receptors that react differently. Tailoring treatment could mean fewer trial-and-error months.
And while opioid prescriptions have dropped since 2012, over 73 million Americans still need them for chronic pain. That means OIC isn’t going away. But the tools to manage it are getting smarter, faster, and more accessible - if we push for better insurance coverage and earlier intervention.
Final Thought: This Isn’t Normal - Don’t Accept It
If you’re on opioids and you’re constipated, you’re not broken. You’re not lazy. You’re not failing. You’re experiencing a known, predictable side effect of a powerful drug. And there are real, effective solutions.
Don’t wait until you’re in pain. Don’t assume laxatives will fix it. Talk to your doctor about starting PEG right away. Ask about PAMORAs if you’re still struggling after a few weeks. Bring your bowel log. Push for coverage. You deserve to manage your pain without sacrificing your quality of life.
Can opioid-induced constipation go away on its own?
No. Unlike other opioid side effects like drowsiness or nausea, constipation doesn’t improve with time. It persists as long as you’re taking opioids because the mechanism - slowed gut movement - doesn’t adapt. Without treatment, it typically gets worse. That’s why proactive management is critical.
Are over-the-counter laxatives enough for opioid-induced constipation?
For many people, no. While osmotic laxatives like polyethylene glycol (Miralax) are the best OTC option, studies show that 68% of patients still need prescription medications like PAMORAs for adequate relief. OIC is caused by a specific biological block, not just slow motility, so standard laxatives often fall short.
What are the safest long-term laxatives for opioid users?
Polyethylene glycol (PEG) is the safest long-term option. It’s not absorbed by the body, doesn’t cause dependency, and works by drawing water into the colon naturally. Stimulant laxatives like senna can be used short-term but shouldn’t be the mainstay. Avoid stimulants daily for more than a few weeks unless supervised.
Do PAMORAs reduce pain relief?
No. PAMORAs are designed to block opioid receptors only in the gut, not in the brain. Clinical trials show they relieve constipation without affecting pain control. Patients report the same level of pain relief while having regular bowel movements. This is what makes them different from older treatments.
Can I take PAMORAs if I’ve had bowel surgery?
Not without caution. PAMORAs carry a risk of gastrointestinal perforation, especially in people with a history of bowel obstruction, recent surgery, or inflammatory bowel disease. If you’ve had abdominal surgery in the past 6 months, your doctor will likely avoid PAMORAs or require extra monitoring. Always disclose your full surgical history.
Why do some doctors not talk about OIC?
Many providers still see constipation as a minor side effect or assume patients will bring it up. But studies show 78% of patients don’t mention it unless asked. Also, primary care doctors often lack time or training in pain management. Palliative care teams are much better at managing OIC - that’s why 85% of them use proactive treatment, compared to only 32% in primary care.
Is there a cure for opioid-induced constipation?
There’s no cure - because the cause is the opioid itself. But there are highly effective treatments that let you keep your pain relief while restoring normal bowel function. The goal isn’t to stop opioids; it’s to manage the side effect so you can live well while taking them.
