Acetaminophen and Constipation: Side Effects and Coping Tips

Short answer: Yes, acetaminophen (paracetamol) can be associated with constipation in some people, though it’s generally less common and usually milder than constipation caused by opioid pain medicines. ^[1] Constipation is specifically highlighted as a possible adverse effect in official drug labeling for acetaminophen products. ^[2]

Is constipation a known acetaminophen side effect?

• Official labeling lists constipation among reported adverse reactions for acetaminophen-containing products. ^[1] This appears across multiple acetaminophen monographs and combination products’ labels. ^[2]
• Opioid/acetaminophen combinations (e.g., oxycodone + acetaminophen) frequently cause constipation because opioids slow gut movement; this effect is well described and can be severe. ^{[3] [4]}
• Population studies suggest an association between regular acetaminophen use and chronic constipation, although they cannot prove causation and other factors may contribute. [PM18]

How common is it?

• Precise “how often” is not consistently quantified on acetaminophen labels, but constipation is recognized as a possible side effect. ^{[1] [2]}
• When acetaminophen is combined with an opioid, constipation becomes common and clinically significant due to opioid effects on intestinal motility. ^{[3] [4]} Labels advise patients about the risk of severe constipation and when to seek care. ^[5]

Why might constipation happen?

• Pure acetaminophen: The exact mechanism for constipation is not well defined; reports exist in labeling and observational data. ^[1] [PM18]
• Opioid combinations: Opioids reduce propulsive contractions of the bowel and increase muscle tone, which can lead to spasms and constipation. ^{[3] [4]}

Practical ways to cope and prevent constipation

Lifestyle and diet

• Hydration: Aim for adequate fluids unless your clinician has you on fluid restriction. This helps soften stool. ^[6]
• Fiber intake: Gradually increase dietary fiber (whole grains, fruits, vegetables) to support regular bowel movements. ^[7]
• Physical activity: Gentle, regular movement can stimulate bowel motility. ^[6]

Over-the-counter options

• Stool softeners (e.g., docusate): Increase water in stool, making it easier to pass; they generally have few side effects. ^[8]
• Osmotic laxatives (e.g., polyethylene glycol): Draw water into the bowel to ease passage; often effective for medication-related constipation. ^[8]
• Bulk-forming agents (e.g., psyllium): Can help if you’re drinking enough water; increase fluids to avoid worsening constipation. ^[7]

When using opioid/acetaminophen combinations

• Proactive prevention is recommended because opioid-induced constipation is common and patients do not develop tolerance to it. [PM14] Labels advise specific constipation management and vigilance. ^[5]
• Ask about targeted therapies if constipation persists despite standard measures; your clinician may consider medications specifically for opioid-induced constipation. [PM20]

When to seek medical advice

• No bowel movement for 3 days, new rectal bleeding, severe abdominal pain, or vomiting warrant contacting your healthcare provider. ^[6]
• If constipation started after you began acetaminophen or an opioid/acetaminophen product, ask whether your regimen should be adjusted and review other medications that may contribute. ^[9]

Practical medication tips

• Use the lowest effective dose for the shortest time to reduce side effect risk while still controlling pain. [PM16]
• Review all pain medicines: If you’re on an opioid/acetaminophen combination, consider whether non-opioid options or multimodal strategies might reduce constipation risk. [PM16]
• Discuss other contributors: Some medicines (e.g., anticholinergics) can worsen constipation when taken with opioid-containing products. Monitoring is advised. ^[10]

Key takeaways

• Constipation can occur with acetaminophen, and is well recognized, especially in opioid/acetaminophen combinations. ^{[1] [3]}
• Most cases can be managed with fluids, fiber, activity, and simple laxatives; seek care if symptoms are severe or persistent. ^{[6] [8]}
• Talk with your clinician about your full medication list to tailor a plan and minimize constipation risk. ^[9]