Dulcolax vs. Miralax

Main Difference

The main difference between Dulcolax and Miralax is that Dulcolax contains Bisacodyl and Miralax contains polyethylene glycol.

Dulcolax vs. Miralax — Is There a Difference?

Difference Between Dulcolax and Miralax

Dulcolax vs. Miralax

Dulcolax contains Bisacodyl as an active therapeutic agent, on the other hand, Miralax contains polyethylene glycol

Dulcolax vs. Miralax

Dulcolax pills and suppositories are available while Miralax liquids are available.

Dulcolax vs. Miralax

Dulcolax half-life is 16 hrs; on the other hand, Miralax half-life is 4-6 hrs.

Dulcolax vs. Miralax

Dulcolax is not the treatment of chronic constipation, while Miralax is the treatment of chronic constipation.

Dulcolax vs. Miralax

Dulcolax causes bowel movement in 6-12 hrs, on the other hand, Miralax takes 1-3 days for a bowel movement.

Dulcolax vs. Miralax

Dulcolax treats constipation after spinal cord injury, on the other hand, Miralax cannot treat constipation after spinal cord injury.


Comparison Chart

Dulcolax is stimulant laxative and used to treat constipation.Miralax is a drug that treats constipation.
Drug Category
Stimulant LaxativeStimulant Laxative
Active Therapeutic Moiety
BisacodylPolyethylene glycol
Mechanism of Action
Increases the bowel movementIncreases the bowel movement
Therapeutic Uses
Treats constipation
Clean out intestine before a bowel examination
Clean out intestine before bowel surgery
Treats occasional constipation
Stimulates bowel movements
Chronic constipation

Dulcolax vs. Miralax

Dulcolax is a brand of Bisacodyl; on the other hand, Miralax is a brand of polyethylene glycol. Dulcolax is available as a pill and suppository while Miralax is available as a liquid. Dulcolax has a half-life of 16hrs; on the other hand, Miralax has a half-life of 4-6 hrs. Dulcolax cannot relieve chronic constipation, whereas Miralax relieves chronic constipation. Dulcolax treats constipation caused by spinal cord injury. On the other hand, Miralax can not treat constipation caused by spinal cord injury. Dulcolax starts to show its therapeutic action in 6-12 hrs; on the other hand, Miralax starts to show its therapeutic action in 1-3 days.

What is Dulcolax?

Dulcolax contains Bisacodyl which is derivative of the triphenylmethane. Dulcolax is the stimulant laxative and is used to relieve constipation. Dulcolax increases the bowel movement so treats the chronic type of constipation and manages the neurogenic bowel dysfunction by evacuating the colon. Dulcolax also prepares the bowel for the colonoscopy. Dulcolax causes the peristalsis by stimulating the enteric nerves. Dulcolax is also classified under contact laxative because it increases salt and fluid secretion. The action of Dulcolax on small intestine is almost negligible. Dulcolax is taken by mouth and when using without the recommendation of a doctor, then follow all the instructions on the package. Do not take Dulcolax within 1 hr of the use of milk or dairy products and antacid because if taken with these, then it may lead to the removal of coating of the tablet and can upset the stomach. Dulcolax may take 6-12 hrs before it causes the bowel movement and does not use this drug for more than seven days. Unwanted effects may occur if this drug is used in excess, and these include nausea, abdominal pain, cramping, diarrhea, and weakness. If unwanted effects get worse, then inform pharmacist or doctor. Inform the doctor as soon as possible if dizziness, fainting, irregular heartbeats, mood changes, and allergic reaction appears. Dulcolax evacuates intestine in two phases. After a few hrs of the ist evacuation, there would be a secondary action phase, and it will continue until all drug eliminates from the body.

What is Miralax?

Miralax is the drug that relieves constipation. Miralax has polyethylene glycol as an active drug, which is the basis of many laxatives. Polyethylene Glycol is hydrophilic, and due to its hydrophilic nature, Polyethylene Glycol holds water in the stool, and it helps softens the stool. Polyethylene Glycol increases bowel movements. Miralax belongs to osmotic laxatives. Miralax does not cause cramps, and due to this reason, Miralax is different from other available laxatives. Miralax is considered the most prescribed drug by physicians for constipation. The unique feature of the Miralax is that Miralax is free of sugar and gluten. Miralax can be used by dissolving in favorite beverages. Miralax is easy to take than engulfing a pill for relieving constipation. Miralax is not used in the children. Miralax is not prescribed to 16 years of age or younger than 16 years children. Miralax does not show therapeutic action quickly; rather, Miralax takes 2-4 days. Miralax is not recommended for more than seven days and in case of constipation is not relieved in this period, then it should be discontinued and inform the prescriber. Miralax is prescribed once daily, but its dose can be adjusted according to the condition of the patient. Miralax intake may cause nausea or gas trouble as the unwanted effect or in the rare case an abdominal cramp. If the patient is found to be allergic to polyethylene Glycol, then Miralax use must be stopped.


The conclusion of the above discussion is that Dulcolax and Miralax both are used to treat constipation, and they contain two different active moieties.