Compare Dulcolax vs. lactulose

Head-to-head comparisons of medication uses, side effects, ratings, and more.

Dulcolax
(bisacodyl)

Generlac
(lactulose)

Treats constipation. Dulcolax (Bisacodyl) works fast and the suppositories work even faster to relieve your constipation, as long as you're okay with it "cramping" your style a bit.Relieves constipation and gets rid of ammonia in people with liver problems. Generlac (lactulose) relieves constipation and high ammonia levels, but it can take up to 48 hours to work.
Reviews & ratings
Filter group. All currently selected
Filter group. All currently selected
5.14Dulcolax
Reviews for Dulcolax
65%
of people (All ages) say Dulcolax is worth it
49%
say it works well
16%
say it's a big hassle
160 reviews
Have you used Dulcolax (bisacodyl)?
Worth itNot sureNot worth it

Not enough reviews for this treatment. Help someone out, leave a review!

Have you used Generlac (lactulose)?
Worth itNot sureNot worth it
Side effects
Dulcolaxlactulose

We haven’t found good data for Dulcolax side effects.

FDA side effect reports for Dulcolax »

The lactulose FDA package insert doesn’t have numbers about how common side effects are.

More about lactulose side effects »
How it works
Dulcolaxlactulose
Dulcolax (Bisacodyl) is a stimulant laxative that you can take by mouth or in a suppository. It causes waves of contractions (peristalsis) in your intestine muscles to push stool through. It also makes stool more watery.Generlac (lactulose) draws water into the intestines to soften your stool for easier passing. It also helps draw ammonia into your stool for removal from the body.
Type of medication
Dulcolaxlactulose
Over-the-counterPrescription only
Available as
Dulcolaxlactulose
  • Pill
  • Suppository
  • Liquid
  • Powder
Used for
Dulcolaxlactulose
Risk factors for serious side effects
Dulcolaxlactulose
  • Age 60 or older
  • Malignancy
  • Other condition that causes blockage or narrowing of bowel
  • Taking medications that cause constipation
  • Age 60 or greater
Detailed Dulcolax (bisacodyl) risks & warnings »
  • Taking Generlac (lactulose) for more than 6 months
  • Elderly
  • Taking medications that cause mineral imbalance
  • Not exercising regularly
  • Diabetes
Detailed Generlac (lactulose) risks & warnings »
Pregnancy

Research studies with animals found harmful effects on unborn babies. It hasn’t been properly studied in humans. The benefits might outweigh the risks even if you’re pregnant. Talk with your doctor.

Food
Dulcolaxlactulose
  • Talk to you doctor about eating certain foods and getting more exercise to help prevent your constipation.
No food related info.
Pain
Dulcolaxlactulose
  • Don't take if you have stomach pain, nausea, vomiting, or had sudden changes in your stool for more than 2 weeks.
No pain related info.
Upsides and benefits
Dulcolaxlactulose
  • Most people said it was worth taking and it wasn't too much of a hassle.
  • Tablets give overnight relief of your constipation.
  • Dulcolax can also be used to treat constipation caused by spinal cord injury.
  • Suppositories give you quick relief without having to drink a large amount of liquid medicine.
  • Generlac (lactulose) is the first-choice treatment for brain conditions caused by high ammonia levels.
  • Can be used if you have severe chronic constipation leading to blockage.
  • Available in generic.
  • Can be taken orally or rectally.
Downsides and risks
Dulcolaxlactulose
  • Dulcolax can cause cramping, stomach upset, feeling faint, and the feeling that you "have to go right now".
  • You have to be comfortable with putting the medicine in your rectum.
  • Suppositories can cause slight rectal burning.
  • Should not be used if you are on a galactose-restricted diet.
  • Does not provide rapid relief of constipation. Talk to your doctor or pharmacist if you need quick relief.
  • Generlac (lactulose) has a very sweet flavor that most people don't like.
Tips from our pharmacists for people taking the medication
Dulcolaxlactulose
  • Swallow tablets whole (don't chew or crush) at bedtime, but not for more than one week.
  • Tablet works in 6 to 12 hours. Suppository works in 15 minutes to an hour, so make sure you're near a bathroom.
  • Don't take tablets within 1 hour of taking antacids, milk or dairy products.
  • Be sure to remove the wrapper from the suppository before inserting it into your rectum.
  • Ask your doctor about giving Dulcolax to anyone younger than 6 years.
  • Don't take if you have stomach pain, nausea, vomiting, or had sudden changes in your stool for more than 2 weeks.
  • Check with your baby doctor before using or if you're breast-feeding.
  • Talk to you doctor about eating certain foods and getting more exercise to help prevent your constipation.
  • Generlac (lactulose) works within 24 to 48 hours to produce a bowel movement.
  • If you are taking this for constipation, it is usually taken once a day.
  • The goal is for you to have 2 to 3 stools a day.
  • You can mix the oral solution in juice, water, or milk for better taste.
  • Generlac (lactulose) can cause you to be dehydrated, so make sure you drink plenty of fluids.
  • Maintaining a healthy diet, regular exercise, and drinking plenty of fluids can help you prevent constipation.
Learn more
More about DulcolaxSide effectsReviews & ratingsAlternativesFDA package insert
Have you used Dulcolax (bisacodyl)?
Worth itNot sureNot worth it
More about lactuloseSide effectsReviews & ratingsAlternativesFDA package insert
Have you used Generlac (lactulose)?
Worth itNot sureNot worth it