Duphalac (Lactulose) vs Other Laxatives: Complete Comparison

When you’re battling stubborn constipation, the first question is usually “which laxative actually works for me?” Duphalac is the brand name for lactulose, a synthetic sugar that draws water into the colon and softens stool. It’s been a go‑to prescription in Australia for decades, but a growing menu of over‑the‑counter (OTC) options means you have more choices than ever.

Key Takeaways

• Duphalac works by changing the osmotic balance in the gut; it’s ideal for chronic constipation and hepatic encephalopathy.
• OTC options such as polyethylene glycol (Miralax) and magnesium‑based laxatives act faster but may cause electrolyte shifts.
• Stimulant laxatives (senna, bisacodyl) are best for occasional relief, not long‑term use.
• Fiber supplements address diet‑related constipation and can be combined with osmotic agents.
• Safety, drug interactions, and personal health conditions dictate the best choice.

How Duphalac (Lactulose) Works

Lactulose is a disaccharide composed of galactose and fructose. It’s not absorbed in the small intestine, so it reaches the colon intact. Once there, gut bacteria ferment it into short‑chain fatty acids, pulling water into the lumen and softening the stool. This osmotic effect also lowers colonic pH, which helps trap ammonia in patients with liver disease.

Typical dosing in Australia starts at 15‑30 mL once daily for chronic constipation, adjustable up to 60 mL. It may take 24‑48 hours to notice a change, which feels slower than some OTC products but offers a gentler, longer‑lasting effect.

When Duphalac Is the Right Pick

Duphalac shines in two main scenarios:

1. Chronic constipation where daily dosing is needed without the risk of habit‑forming stimulant laxatives.
2. Hepatic encephalopathy management, because the same osmotic action traps ammonia.

Because it’s a prescription medication in Australia, you’ll need a doctor’s approval. The Therapeutic Goods Administration (TGA) rates it as a Schedule 4 drug, reflecting its safety profile when used under supervision.

Overview of Common Alternatives

Below are the most frequently used alternatives, each with a quick snapshot.

• Miralax (polyethylene glycol 3350) - an OTC osmotic laxative that holds water in the stool.
• Senna (stimulant laxative derived from the Senna plant) - promotes bowel muscle contractions.
• Bisacodyl (synthetic stimulant laxative) - works quickly, often within 6‑12 hours.
• Magnesium Hydroxide (commonly known as Milk of Magnesia) - an osmotic laxative that also supplies magnesium.
• Fiber supplements (e.g., psyllium husk) - increase stool bulk and improve regularity.

Detailed Comparison Table

Pros and Cons at a Glance

Duphalac (Lactulose)

• Pros: gentle, safe for long‑term use, dual benefit for liver patients, low risk of tolerance.
• Cons: slower onset, prescription needed, taste can be unpleasant for some.

Miralax

• Pros: fast‑acting, easy powder form, widely available.
• Cons: may cause bloating, less suited for hepatic encephalopathy.

Senna & Bisacodyl

• Pros: rapid results, inexpensive.
• Cons: can cause cramping, not ideal for daily use, risk of electrolyte imbalance.

Magnesium Hydroxide

• Pros: adds magnesium, useful for people with low Mg levels.
• Cons: can lead to hypermagnesemia in kidney disease, may worsen diarrhea.

How to Choose the Right Laxative for You

Consider these three decision points:

1. Underlying health condition: If you have liver cirrhosis, Duphalac’s ammonia‑trapping effect is a game‑changer.
2. Frequency of constipation: Chronic cases merit a daily, gentle agent (Duphalac, Miralax, fiber). Sporadic flare‑ups can be managed with stimulants.
3. Medication interactions: Stimulants may interfere with anticholinergic drugs, while magnesium can clash with certain antibiotics or heart meds.

Always run new choices past your GP or pharmacist, especially if you’re on blood thinners, diuretics, or have renal issues.

Practical Tips for Using Laxatives Safely

• Start low: For Duphalac, begin with 15 mL and increase only if stool remains hard after a week.
• Stay hydrated: Osmotic agents pull water into the colon, so drink at least 2 L of fluid daily.
• Combine with fiber: Adding 5 g of psyllium husk can improve stool bulk without extra medication.
• Avoid long‑term stimulant use: More than two weeks of senna or bisacodyl can cause dependency.
• Watch electrolytes: If you use magnesium‑based laxatives for > 2 weeks, get a serum magnesium check.

Frequently Asked Questions

Bottom line: if you need a gentle, long‑term solution and have any liver concerns, Duphalac remains the solid choice. For quick fixes or budget‑friendly options, Miralax, senna, or magnesium‑based products can fill the gap-just respect the dosage and watch for side effects.