lactulose vs polyethylene glycol 3350
Side-by-side comparison of lactulose and polyethylene glycol 3350 Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.
Enulose, Kristalose
MiraLAX
Lactulose is a medicine that helps treat and prevent problems with your brain caused by liver disease. It works by reducing the amount of ammonia in your blood.
MiraLAX is a laxative medicine. It helps to relieve constipation by drawing water into your stool, making it easier to pass.
This medicine treats and prevents portal-systemic encephalopathy. This condition can happen when your liver isn't working well. Lactulose helps lower ammonia levels in your blood, which can improve your mental state and brain function.
MiraLAX treats occasional constipation, which means you have irregular bowel movements. It usually helps you have a bowel movement within 1 to 3 days. Do not use for more than 7 days.
Lactulose is a sugar that is not digested in your body. It travels to your colon where it is broken down by bacteria. This process makes the colon more acidic, which helps to draw ammonia from the blood into the colon, where it is then removed from the body through bowel movements.
MiraLAX is an osmotic laxative. It works by drawing water into your colon. This softens the stool and makes it easier to pass, relieving constipation.
- • Gas
- • Bloating
- • Belching
- • Abdominal discomfort
- • Cramping
- • Diarrhea
- • Nausea
- • Headache
- • Abdominal pain
- Feeling sick to your stomach 2,523
- Having trouble passing stool 2,497
- Accidentally losing your balance and hitting the ground 2,240
- Throwing up 2,047
- Feeling very tired 2,028
- Problem with using the product 9,862
- The medicine did not work 9,563
- Using the medicine for something it's not approved for 8,883
- Diarrhea 6,828
- Nausea 5,306
If you need a low-galactose diet, you should not take this medicine. Lactulose solution contains galactose.
Do not use more than directed unless your doctor tells you to. Ask a doctor if you are 16 years old or younger.
Tell your doctor if you are pregnant or breastfeeding before taking this medicine. It is not known if lactulose can harm your unborn baby. It is also not known if lactulose passes into breast milk.
It is not known if MiraLAX is safe to use during pregnancy or while breastfeeding. Talk to your doctor before using this medicine if you are pregnant or breastfeeding.
How to Read This lactulose vs polyethylene glycol 3350 Comparison
lactulose is classified in the Osmotic Laxative drug class, while polyethylene glycol 3350 sits within the Osmotic Laxative class. Because both drugs share the same classification, they are often considered interchangeable in theory — but clinical outcomes rarely track that cleanly. Both drugs are split between OTC and prescription status, which affects access and supervision.
Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, lactulose has 11,335 submissions while polyethylene glycol 3350 has 40,442. Those figures reflect cumulative reporting volume — not per-patient risk — so older, widely dispensed drugs typically look worse on count alone. No direct interaction between these two drugs is listed in our FDA-derived dataset, though co-prescription still warrants pharmacist review. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.
A table cannot substitute for clinical judgment. Effectiveness, tolerability, drug-drug interactions with your other medications, kidney and liver function, pregnancy status, insurance formulary, and price all feed into a decision that only a licensed prescriber can make responsibly. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This page is for educational purposes only, is not medical advice, and should not be used to self-switch between lactulose and polyethylene glycol 3350 — always consult your physician or pharmacist first.
Important: This comparison is for informational purposes only. Drug effects vary between individuals. Always consult your doctor or pharmacist for personalized medical advice.