Duphalac (Lactulose) vs. Common Laxative Alternatives: Detailed Comparison
Laxative Comparison Tool
Select Your Needs
When constipation strikes, the first question is usually "What should I take?" Duphalac (the brand name for lactulose) is a go‑to prescription for many, but there are plenty of over‑the‑counter options that claim similar results. This guide lays out the facts you need to decide which laxative fits your lifestyle, budget, and health profile.
TL;DR
- Duphalac (lactulose) is a prescription osmotic laxative best for chronic constipation and hepatic encephalopathy.
- Polyethylene glycol (Miralax) works faster, costs less, and is OTC.
- Stimulant agents like senna and bisacodyl act quickly but can cause cramps.
- Mineral salts (magnesium citrate) are good for short‑term use but may affect electrolytes.
- Fiber supplements (psyllium) treat mild constipation and improve gut health over time.
What is Duphalac (Lactulose)?
Duphalac is a prescription‑only osmotic laxative containing the disaccharide lactulose. It was first approved in the 1960s and is widely used to treat chronic constipation and to lower blood ammonia in patients with liver disease. The product comes in liquid form, typically 10g per 15ml bottle, and is taken once or twice daily depending on the condition.
How Lactulose Works
When you swallow lactulose, it isn’t absorbed in the small intestine. Instead, it reaches the colon where gut bacteria break it down into short‑chain fatty acids. This process draws water into the colon (osmotic effect), softening stool and stimulating peristalsis. The same fermentation also lowers colon pH, helping convert ammonia to non‑absorbable ammonium, which is why it’s essential for hepatic encephalopathy management.
Key Attributes to Consider
- Dosage & Administration: 15‑30ml daily for constipation; 30‑45ml for liver patients. Requires mixing with water or juice.
- Onset of Action: 24‑48hours; not a rapid‑relief option.
- Side Effects: Bloating, flatulence, mild cramping. Long‑term use can cause electrolyte shifts if not monitored.
- Cost: Approx. CAD15‑20 per bottle (10ml). Usually covered by provincial drug plans for chronic conditions.
- Contraindications: Galactosemia, severe bowel obstruction, acute intestinal inflammation.
Popular Alternatives
Below are the most frequently recommended laxatives that sit alongside Duphalac in treatment algorithms.
Miralax (polyethylene glycol 3350, an OTC osmotic laxative) comes as a flavorless powder mixed with liquid. It typically produces a bowel movement within 1‑3 days and is praised for minimal cramping.
Senna (a plant‑derived stimulant laxative found in tablets and teas) triggers colonic contractions within 6‑12 hours, making it suitable for occasional relief.
Bisacodyl (a synthetic stimulant laxative available as tablets or suppositories) works in 6‑10 hours and can be used for bowel prep before procedures.
Magnesium citrate (an inorganic mineral salt that draws water into the colon) is often used for rapid emptying before surgeries; dosage must be timed to avoid dehydration.
Psyllium husk (a soluble fiber supplement that absorbs water and bulks stool) is ideal for mild constipation and offers cardiovascular benefits when taken regularly.
Glycerin suppositories (a rectal osmotic agent that softens stool locally) provide fast relief for hemorrhoidal patients but are not meant for long‑term use.
Side‑by‑Side Comparison
| Attribute | Duphalac (Lactulose) | Miralax (PEG3350) | Senna | Bisacodyl | Magnesium citrate | Psyllium husk | Glycerin suppository |
|---|---|---|---|---|---|---|---|
| Type | Osmotic (prescription) | Osmotic (OTC) | Stimulant (herbal) | Stimulant (synthetic) | Mineral salt (osmotic) | Fiber (bulking) | Rectal osmotic |
| Onset | 24‑48h | 1‑3days | 6‑12h | 6‑10h | 30‑60min | 24‑48h | 15‑30min |
| Typical Dose | 15‑30ml daily | 17g (≈1scoop) daily | 17‑34mg (1‑2 tablets) nightly | 5‑10mg tablets | 10‑30ml oral solution | 5‑10g with water | 1suppository (2‑3g) |
| Cost (CAD) | ≈15‑20 per bottle | ≈12 per box (30scoops) | ≈8 per pack | ≈10 per bottle | ≈7 per bottle | ≈6 per container | ≈5 per pack |
| Key Side Effects | Flatulence, bloating | Loose stools, nausea | Abdominal cramps | Cramping, electrolyte loss | Diarrhea, hypermagnesemia | Gas, bloating | Rectal irritation |
| Best For | Chronic constipation, liver disease | Gentle daily stool softening | Occasional rapid relief | Pre‑procedure bowel prep | Quick emptying before surgery | Mild constipation & heart health | Hemorrhoid‑related straining |
| Not Ideal For | Acute abdominal pain, obstruction | Patients needing immediate relief | Long‑term daily use | Kidney disease (electrolyte risk) | Severe kidney disease | Severe constipation needing rapid action | Regular constipation management |
Choosing the Right Option
Think of the decision as a checklist. Ask yourself:
- How quickly do I need relief? If you need a bowel movement in under an hour, a glycerin suppository or magnesium citrate wins.
- Do I have a chronic condition? For ongoing constipation or liver‑related ammonia control, Duphalac offers a dual benefit that OTC products lack.
- What’s my budget? Miralax and psyllium provide cost‑effective daily use, while prescription lactulose can be pricier without insurance.
- Any medical restrictions? Stimulants (senna, bisacodyl) should be avoided in patients with IBD flare‑ups, whereas osmotic agents are safer for those groups.
- Do I want extra health perks? Psyllium adds cholesterol‑lowering fiber, and magnesium citrate supplies a mineral needed for muscle function.
Match the answers against the comparison table. If you tick “chronic + liver” and “can afford prescription,” Duphalac stays on top. If you need a cheap, gentle daily routine, Miralax or psyllium are better fits.
Frequently Asked Questions
Frequently Asked Questions
Can I use Duphalac for occasional constipation?
Yes, but because it takes 24‑48hours to work, many patients prefer faster‑acting OTC options for occasional bouts. Duphalac shines when constipation is chronic or when you also need to manage liver‑related ammonia.
Is lactulose safe for children?
Pediatric dosing exists, but it should only be used under a doctor’s supervision. In children, the risk of electrolyte imbalance is higher, so many clinicians start with a lower dose and monitor stool frequency.
How does Miralax compare cost‑wise to Duphalac?
A typical 30‑scoop bottle of Miralax costs around CAD12, while a 15ml bottle of Duphalac is about CAD15‑20. For daily use, Miralax is generally cheaper, especially when insurance doesn’t cover lactulose.
Will lactulose interact with other medications?
Lactulose can affect the absorption of some drugs, such as antibiotics that rely on a specific pH. Always tell your pharmacist about all medicines you’re taking to avoid reduced efficacy.
Can I switch from Duphalac to an OTC alternative?
You can, but taper down lactulose gradually to avoid rebound constipation. Talk to your doctor about a transition plan that may involve a short overlap of both agents.
Bottom line: Duphalac remains a solid choice for long‑term constipation and liver‑related needs, while a spectrum of OTC alternatives offers faster relief, lower cost, or added health benefits. Use the comparison table and checklist above to match a product to your specific situation.
About Author
I am a passionate pharmaceutical researcher. I love to explore new ways to develop treatments and medicines to help people lead healthier lives. I'm always looking for ways to improve the industry and make medicine more accessible to everyone.
Annette van Dijk-Leek September 28, 2025
Hey there! If you’re feeling stuck with constipation, remember you’ve got options!! Duphalac can be a solid choice for chronic issues, but don’t forget about the cheaper over‑the‑counter pals like Miralax or psyllium!! Stay positive, try a small dose, hydrate like crazy, and you’ll be back on track in no time!!! 🌟
Katherine M September 30, 2025
Esteemed readers, the comparative analysis presented herein invites a reflective contemplation on the physiological ramifications of osmotic versus stimulant laxatives. One might consider the nuanced interplay between efficacy, cost, and patient compliance, particularly within diverse sociodemographic cohorts. 😊
Bernard Leach October 2, 2025
When evaluating laxatives one must begin with a clear understanding of osmotic mechanisms and how they differ from stimulant actions. Lactulose functions by drawing water into the colon through bacterial fermentation of the disaccharide. This process results in softer stool and increased peristalsis over a period of twenty four to forty eight hours. In contrast agents such as senna trigger direct colon muscle contractions within six to twelve hours. The onset of magnesium citrate is even more rapid often producing evacuation within thirty to sixty minutes. Polyethylene glycol provides a gentle osmotic effect that typically manifests within one to three days. The choice of agent therefore hinges on the clinical scenario and patient preference. Chronic constipation may benefit from the steady action of lactulose while occasional relief can be achieved with stimulant agents. Cost considerations also play a pivotal role especially when insurance coverage is limited. Over‑the‑counter options like Miralax and psyllium present economical alternatives to prescription products. However one must remain vigilant for potential side effects such as electrolyte disturbances with magnesium based preparations. Fiber supplements contribute additional health benefits beyond bowel regularity including cholesterol reduction. It is essential to monitor patient response and adjust dosing accordingly. A systematic approach that incorporates diet, hydration, and physical activity augments pharmacologic therapy. Ultimately individualized care maximizes therapeutic outcomes and patient satisfaction.