MiraLAX is a brand-name, over-the-counter (OTC) medication. It’s classified as an osmotic laxative.

MiraLAX is used to treat constipation. It’s typically used for short-term treatment, but in some cases, it’s used long-term to treat chronic (long-lasting) constipation. MiraLAX is also sometimes used for colonoscopy bowel preparation.

For most people, taking MiraLAX will cause a bowel movement within one to three days of taking it. One study of its effectiveness focused on people who had fewer than two bowel movements per week. MiraLAX increased their number of bowel movements to 4.5 per week, compared to 2.7 per week in people taking a placebo.

Another study found that 52 percent of people with chronic constipation were successfully treated with MiraLAX.

MiraLAX comes as a flavorless powder that you mix with four to eight ounces of water, juice, or other liquid. The powder comes in bottles or single-serve packets.

MiraLAX contains the ingredient polyethylene glycol 3350 (PEG 3350).

MiraLAX is also available in generic versions, which are usually store brands. These store brands often cost less than brand-name MiraLAX.

MiraLAX is approved for over-the-counter (OTC) use in adults and adolescents aged 17 years and older. It’s also effective for treating constipation in younger children, including babies younger than 2 years of age.

According to the North American Society of Pediatric Gastroenterology, MiraLAX is a first-choice medication for treating and preventing constipation in children. However, it shouldn’t be used in young children without the direction of your child’s doctor.

MiraLAX dosage will depend on several factors. These include:

  • the reason MiraLAX is being used
  • the age of the person using MiraLAX

Typically, you should use the smallest dosage that provides the desired effect.

The following information describes dosages that are commonly used or recommended. If you’re unsure about what dosage to use, ask your doctor or pharmacist.

Dosage for kids, toddlers, and infants

Before giving MiraLAX to your child, talk with your child’s doctor. They can recommend the most appropriate dosage of MiraLAX for your child. The manufacturer of MiraLAX doesn’t provide this information. They advise getting a doctor’s recommendation for children’s dosage.

It’s also important to talk to your child’s doctor because they may want to evaluate your child to determine the cause of constipation. Depending on the cause, other treatments may be needed.

Dosage for adults

The typical dosage of MiraLAX for adults is 17 grams. The product will come with a measuring cap or device to help you determine the correct dose.

The powder is mixed and dissolved in four to eight ounces of water or another beverage and consumed once daily.

What if I miss a dose?

If you miss a dose, take it as soon as you remember. If it’s almost time for your next dose, just take that one dose. Don’t try to catch up by taking two doses at once.

Will I need to use this drug long-term?

MiraLAX is intended for the short-term treatment of constipation. If you have chronic (long-lasting) constipation, you should be evaluated by your doctor. Your doctor will decide the best treatment for you, which may include long-term treatment with MiraLAX.

MiraLAX can cause mild or serious side effects. The following list contains some of the key side effects that may occur while taking MiraLAX. This list does not include all possible side effects.

For more information on the possible side effects of MiraLAX, or tips on how to deal with a troubling side effect, talk with your doctor or pharmacist.

More common side effects

The more common side effects of MiraLAX include:

  • diarrhea or loose stools
  • gas (flatulence)
  • nausea
  • stomach pain
  • bloating

These side effects may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk to your doctor or pharmacist.

Serious side effects

Call your doctor right away if you have serious side effects. Call 911 if your symptoms feel life-threatening or if you think you’re having a medical emergency. Serious side effects and their symptoms can include the following:

  • Dehydration. Diarrhea caused by MiraLAX can cause fluid loss and dehydration. Seniors have a higher risk of diarrhea and dehydration. Symptoms of dehydration include:
    • thirst
    • fatigue
    • dizziness
    • confusion
    • dry mouth
    • irritability
    • no tears when crying (in children)
    • no wet diapers for several hours (in children)
  • Allergic reactions. Although not common, some people can have an allergic reaction to MiraLAX. In rare cases, allergic reactions can be severe and include anaphylaxis. Symptoms of allergic reaction can include:
    • rash
    • itchy skin
    • runny nose
    • trouble breathing
    • swollen lips, tongue, or throat

Diarrhea

Diarrhea or loose stools are side effects of MiraLAX. Diarrhea is more likely to happen if you take more than the recommended dosage. Seniors also have a higher risk of diarrhea.

In one study, about 11 percent of those taking MiraLAX for chronic constipation had diarrhea as a side effect. In seniors, about 13 percent had diarrhea. For those who have diarrhea, the dosage may need to be reduced.

Bloating

Some people who take MiraLAX have bloating. In one study, about 3 percent of people taking MiraLAX for chronic constipation had bloating as a side effect. This side effect may decrease or go away with continued use of MiraLAX.

Nausea

Some people who take MiraLAX have nausea. In one study, about 6 percent of people taking MiraLAX for chronic constipation had nausea as a side effect. This side effect may decrease or go away with continued use of MiraLAX.

Weight gain

Some people have said they gained weight while taking MiraLAX. However, it’s not clear if MiraLAX is the cause of weight gain.

Headache

Some people have said they had headaches while taking MiraLAX. However, it’s not clear if MiraLAX is the cause of headaches.

Long-term side effects

The short-term and long-term side effects of MiraLAX are similar. In a study lasting 12 months, the most common side effects of MiraLAX were:

  • diarrhea or loose stools
  • gas (flatulence)
  • nausea
  • stomach pain
  • bloating

Side effects are more likely to occur in the first weeks of MiraLAX use and may decrease over time.

Side effects in children

The same side effects that occur in adults can also happen in children.

There’s also some concern about other safety problems in children who take MiraLAX. There have been reports to the Food and Drug Administration (FDA) about unusual side effects in some children, such as:

  • anger
  • aggression
  • mood swings
  • tremors
  • seizure

The FDA found that MiraLAX may contain small amounts of chemicals such as ethylene glycol that could cause these side effects if ingested in large amounts. However, a study funded by the FDA found that children taking MiraLAX did not have higher levels of these chemicals in their blood compared to children who weren’t taking MiraLAX.

These side effects have not occurred in clinical studies of MiraLAX in children, and it’s not clear if they’re caused by MiraLAX or something else. The FDA is funding additional research to investigate the concerns.

Despite these concerns, the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition continues to consider MiraLAX a first-choice medication for short- and long-term treatment of constipation in children.

If you have concerns about these side effects, talk with your doctor.

MiraLAX only comes as a powder. You mix MiraLAX powder into four to eight ounces of water or another beverage and drink it as a liquid. MiraLAX itself doesn’t come in a liquid form. It also doesn’t come as a tablet or pill.

Bottles of MiraLAX powder contain either 7 doses, 14 doses, 30 doses, or 45 doses. Also available are boxes containing single-serve packets of MiraLAX powder. The boxes contain 10 or 20 packets each.

According to the American Gastroenterological Association, MiraLAX is considered a first-choice laxative for use during pregnancy. This means it’s safe to use MiraLAX while you’re pregnant.

Although human studies have not evaluated MiraLAX during pregnancy, we know that very little MiraLAX is absorbed by the body. Therefore, it’s unlikely to affect the fetus of a pregnant woman taking MiraLAX. In studies of pregnant animals given MiraLAX, no harm to a fetus was found.

According to the American Gastroenterological Association, MiraLAX is considered low-risk for use during breastfeeding.

Although human studies have not evaluated MiraLAX during breastfeeding, we know that very little MiraLAX is absorbed by the body. Therefore, it’s unlikely to affect a child who breastfeeds while the mother takes MiraLAX.

MiraLAX is an over-the-counter (OTC) drug that’s approved by the Food and Drug Administration (FDA) for certain purposes.

Recommended uses for MiraLAX

MiraLAX is approved for treating short-term constipation. It’s also recommended for other uses.

MiraLAX for constipation

MiraLAX is approved for the short-term treatment of constipation in adults and adolescents aged 17 years and older.

Your doctor may also recommend it for treating constipation in younger children, including babies younger than 2 years of age.

Don’t take MiraLAX for more than seven days without talking to your doctor. Your doctor may want to evaluate the cause of your constipation. Your doctor may find that you need other treatments.

MiraLAX is often recommended by doctors for treating chronic (long-lasting) constipation. The American College of Gastroenterology and the American Society of Colon and Rectal Surgeons recommend MiraLAX as an effective first-choice treatment for chronic constipation.

MiraLAX for colonoscopy prep

MiraLAX may be recommended by your doctor for colonoscopy bowel preparation. This is a procedure to clear out the contents of your gastrointestinal tract before you have a colonoscopy. According to one study, using MiraLAX is effective for this use, but may not be as effective as other options.

If your doctor recommends MiraLAX for bowel prep, you’ll be given specific instructions on how to use it. You may also need to take other medications for this purpose.

MiraLAX for IBS

MiraLAX is sometimes used by people with irritable bowel syndrome (IBS) who have constipation. MiraLAX may improve symptoms of constipation, but it hasn’t been found to improve other symptoms of IBS, such as stomach upset or pain.

MiraLAX for diverticulitis

Some people with diverticulitis also have constipation. If you have diverticulitis and constipation, talk with your doctor. Your doctor may recommend MiraLAX or other laxative options for your constipation. You may also need other treatments.

Uses that are not recommended

Not all potential uses for MiraLAX are recommended.

MiraLAX for weight loss

Some people take laxatives, including MiraLAX, with the hope of losing weight. However, MiraLAX and other laxatives are not effective for weight loss. In addition, they may cause harmful side effects if they’re used inappropriately. These can include diarrhea, dehydration, and electrolyte imbalances.

If you would like to lose weight, don’t use MiraLAX for that purpose. Instead, talk to your doctor about weight-loss approaches that can work well for you.

Take MiraLAX according to the instructions on the package or according to the directions you’ve received from your doctor.

Timing

MiraLAX can be taken at any time of the day. However, it may be best to take it in the morning. That way, if it causes you to have a bowel movement, you’ll be able to go during the day rather than during the night. You should only take MiraLAX once a day, unless your doctor gives you different instructions.

Taking MiraLAX with food

MiraLAX can be taken with or without food.

Your doctor may recommend MiraLAX for colonoscopy bowel preparation. This is a procedure that’s used to clear out the contents of your gastrointestinal tract before you have a colonoscopy. For this purpose, MiraLAX is sometimes used by itself or in combination with other laxatives.

If your doctor would like you to use MiraLAX for bowel prep, they’ll recommend a specific way to use it. Be sure to follow your doctor’s instructions. To give you an idea of what they might be like, here’s an example of bowel prep instructions:

  • The day before your colonoscopy:
    • Begin a clear liquid diet.
    • At 12 pm (noon), take two laxative tablets such as Dulcolax. Also at this time, mix 8.3 ounces of MiraLAX in 64 ounces of a liquid such as Gatorade. This mixture should be refrigerated.
    • At 5:00 pm, drink an 8-ounce glass of the MiraLAX-Gatorade mixture. Do this every 15 minutes until you’ve consumed a total of four 8-ounce glasses of the mixture (total of 32 ounces).
  • The day of your colonoscopy:
    • Five hours before the procedure, drink the remaining 32 ounces of the MiraLAX-Gatorade mixture.
    • Two hours before the procedure, stop all eating and drinking.

Bowel prep procedures will cause diarrhea. Therefore, you should stay near a toilet as you conduct the procedure.

MiraLAX is classified as an osmotic laxative. This means that it works by drawing water into the colon. The water softens the stool and may naturally stimulate the colon to contract. These actions help ease bowel movements.

How long does it take to work?

MiraLAX doesn’t usually cause a bowel movement immediately after it’s taken. For most people, it causes a bowel movement within one to three days after it’s taken. (The timing will be different if it’s used for colonoscopy bowel prep, as described above).

MiraLAX is an osmotic laxative used to treat constipation. There are other osmotic laxatives, and other types of laxatives, that can also be used to treat constipation. Examples of these laxatives include:

  • Osmotic laxatives. These products work by drawing water into the colon (large intestine), which softens the stool and can cause the colon to contract. These effects help to produce a bowel movement. Examples of osmotic laxatives include:
    • lactulose (Enulose, Kristalose)
    • magnesium citrate
    • magnesium hydroxide (Milk of Magnesia)
  • Bulk-forming laxatives. These products work like osmotic laxatives, drawing water into the colon to make the stool softer. But in addition to that, they contain fiber to bulk up the stool, which naturally stimulates movement of the colon to pass the stool. Examples of bulk-forming laxatives include:
    • calcium polycarbophil (FiberCon, Fiber-Lax)
    • wheat dextrin (Benefiber)
    • methylcellulose (Citrucel)
    • psyllium (Konsyl, Metamucil, others)
  • Stool softeners. These products work by drawing water into the stool itself to make it softer and easier to pass. They don’t stimulate a bowel movement, as many laxatives do. Examples of stool softeners include:
    • docusate (Colace, Kao-Tin, Surfak, others)
  • Stimulant laxatives. These products work by irritating the intestines and causing them to contract. They also work by increasing water in the intestines. Both of these actions help cause a bowel movement. Examples of stimulant laxatives include:
    • bisacodyl (Dulcolax, others)
    • senna (Ex-Lax, Senokot, others)

You may wonder how certain products compare to MiraLAX. Below are comparisons between MiraLAX and several other treatments.

MiraLAX vs. Metamucil

MiraLAX and Metamucil are both laxatives, but they work in different ways.

MiraLAX is an osmotic laxative. That means it draws water into the colon, which softens the stool and may naturally stimulate the colon to contract. These actions help ease bowel movements.

Metamucil is a psyllium fiber supplement that works as a bulk-forming laxative. Like osmotic laxatives, Metamucil draws water into the colon and makes the stool softer. But in addition to that, its fiber content bulks up the stool, which naturally stimulates movement of the colon to pass the stool.

Uses

MiraLAX is used for short-term treatment of constipation and long-term treatment of chronic constipation. It’s also used for bowel prep before colonoscopy.

Metamucil is primarily used for preventing constipation. However, it may also be used for short-term treatment of constipation, as well as long-term treatment of chronic constipation. Metamucil is also used to help treat diarrhea, irritable bowel syndrome (IBS), diverticulosis, and high cholesterol.

Drug forms

MiraLAX comes as a powder in bottles and single-serve packets. You mix the powder with four to eight ounces of liquid and drink it once daily.

Metamucil is available as a powder and as a capsule. You mix the powder with 8 ounces of water and drink it one to three times daily. For the capsule, you typically take two to five capsules up to four times daily.

Side effects and risks

MiraLAX and Metamucil have very similar common side effects. These can include:

  • diarrhea or loose stools
  • stomach pain
  • bloating
  • gas (flatulence)
  • nausea

Some people may have more gas or bloating with Metamucil compared to MiraLAX. However, this side effect may decrease or go away with continued use of either product.

Taking Metamucil without adequate liquid can cause choking. Be sure to take Metamucil with at least 8 ounces of liquid. If you have swallowing problems, don’t take Metamucil.

Effectiveness

MiraLAX and Metamucil are both effective for treating constipation, but they have not been compared in clinical studies.

Guidelines from the American College of Gastroenterology and American Society of Colon and Rectal Surgeons recommend increasing dietary fiber or using fiber supplements such as Metamucil as a first-choice option to prevent and treat constipation, including chronic constipation.

They also recommend osmotic laxatives such as MiraLAX for treating constipation, including chronic constipation.

Both MiraLAX and Metamucil usually take one to three days to cause a bowel movement.

MiraLAX vs. Colace

MiraLAX is an osmotic laxative. That means it draws water into the colon, which softens the stool and may naturally stimulate the colon to contract. These actions help ease bowel movements.

Colace is a stool softener. It helps to draw water into the stool itself to make it softer and easier to pass. It doesn’t stimulate a bowel movement, as many laxatives do.

Uses

MiraLAX is used for short-term treatment of constipation and long-term treatment of chronic constipation. It’s also used for bowel prep before colonoscopy.

Colace is used short-term to prevent and to treat constipation. It’s not currently recommended for long-term treatment of chronic constipation. Colace is commonly used after surgical procedures to help prevent constipation.

Drug forms

MiraLAX comes as a powder in bottles and single-serve packets. You mix the powder with four to eight ounces of liquid and drink it once daily.

Colace comes as a capsule you typically take twice daily.

Side effects and risks

Common MiraLAX side effects include:

  • diarrhea or loose stools
  • stomach pain
  • bloating
  • gas (flatulence)
  • nausea

Colace doesn’t commonly cause side effects. In some cases, it causes loose stools. Diarrhea is considered a rare side effect.

Effectiveness

MiraLAX and Colace are both effective for treating constipation. However, their effectiveness hasn’t been compared in clinical studies.

Guidelines from the American College of Gastroenterology and the American Society of Colon and Rectal Surgeons recommend osmotic laxatives, including MiraLAX, for treating constipation, including chronic constipation.

Although Colace is very commonly used to treat constipation, these guidelines don’t recommend it for this use due to a lack of evidence showing benefit.

Both MiraLAX and Colace usually take one to three days to cause a bowel movement.

MiraLAX vs. Dulcolax

MiraLAX is an osmotic laxative. That means it draws water into the colon, which softens the stool and may naturally stimulate the colon to contract. These actions help ease bowel movements.

Dulocolax (bisacodyl) is a stimulant laxative. It works by irritating the intestines and causing them to contract. It also works by increasing water in the intestines. Both of these actions help cause a bowel movement.

Uses

MiraLAX is used for short-term treatment of constipation and long-term treatment of chronic constipation. It’s also used for bowel prep before colonoscopy.

Dulcolax is used for short-term treatment of constipation. It should not be used long-term. Dulcolax may also be used in combination with other laxatives (including MiraLAX) for bowel prep before colonoscopy or other procedures.

Drug forms

MiraLAX comes as a powder in bottles and single-serve packets. You mix the powder with four to eight ounces of liquid and drink it once daily.

Dulcolax comes as tablets and rectal suppositories. Both forms are used once per day.

Side effects and risks

Common side effects from both MiraLAX and Dulcolax include:

  • diarrhea or loose stools
  • bloating
  • gas (flatulence)
  • nausea

The following side effects can occur with both MiraLAX and Dulcolax, but are more common with Dulcolax:

  • stomach pain
  • cramping
  • vomiting
  • diarrhea
  • electrolyte problems such as low potassium

Stimulant laxatives, including Dulcolax, are also more likely to cause laxative dependence when used long-term. This can cause severe constipation when the medication is stopped.

Effectiveness

MiraLAX and Dulcolax are both effective for treating constipation. However, their effectiveness hasn’t been compared in clinical studies.

Guidelines from the American College of Gastroenterology and the American Society of Colon and Rectal Surgeons recommend osmotic laxatives such as MiraLAX for treating constipation, including chronic constipation.

Dulcolax is considered a second-choice option for short-term treatment of constipation. Also, it shouldn’t be used long-term.

Another difference is how long these products take to work. MiraLAX usually takes one to three days to cause a bowel movement. Dulcolax tablets, on the other hand, usually cause a bowel movement within 6 to 12 hours. And Dulcolax suppositories typically do so within 15 minutes to an hour.

MiraLAX vs. milk of magnesia

MiraLAX is an osmotic laxative. That means it draws water into the colon, which softens the stool and may naturally stimulate the colon to contract. These actions help ease bowel movements.

Milk of magnesia (Phillip’s Milk of Magnesia and others) is another name for magnesium hydroxide. It works like an osmotic laxative.

Uses

MiraLAX is used for short-term treatment of constipation and long-term treatment of chronic constipation. It’s also used for bowel prep before colonoscopy.

Milk of magnesia is used for short-term treatment of constipation. It’s not currently recommended for long-term treatment of chronic constipation.

Drug forms

MiraLAX comes as a powder in bottles and single-serve packets. You mix the powder with four to eight ounces of liquid and drink it once daily.

Milk of magnesia is the liquid form of magnesium hydroxide. Milk of magnesia products come as liquid suspensions. They’re usually taken once daily, but may be taken more often if needed.

Magnesium hydroxide products also come as oral tablets or caplets that are typically taken once daily.

Side effects and risks

Common side effects of MiraLAX include:

  • diarrhea or loose stools
  • stomach pain
  • bloating
  • gas (flatulence)
  • nausea

Milk of magnesia and other magnesium hydroxide products can cause the same side effects as MiraLAX, as well as:

  • cramping
  • vomiting
  • chalky taste

If you have kidney problems, you should not use milk of magnesia or other magnesium hydroxide products. These products can cause high magnesium levels in the body, which can cause dangerous side effects such as:

  • muscle weakness
  • low blood pressure
  • confusion
  • heart rhythm changes

Effectiveness

An analysis of studies comparing MiraLAX and milk of magnesia for constipation in children found conflicting results. Some of these studies show that MiraLAX might be slightly more effective than milk of magnesia. However, another study in the analysis found that milk of magnesia may be more effective.

Guidelines for treating constipation in children recommend MiraLAX as a first choice for short- and long-term treatment of constipation. Milk of magnesia is considered a second-choice option.

For adults, guidelines from the American College of Gastroenterology and the American Society of Colon and Rectal Surgeons recommend osmotic laxatives such as MiraLAX for treating constipation, including chronic constipation.

Even though milk of magnesia and other magnesium hydroxide products are very commonly used for treating constipation in adults, these guidelines don’t recommend them for this purpose because there’s not a lot of evidence showing benefit.

Another difference between MiraLAX and milk of magnesia is how long they take to work. MiraLAX usually takes one to three days to cause a bowel movement. Milk of magnesia, on the other hand, usually causes a bowel movement within 30 minutes to 6 hours.

MiraLAX vs. Benefiber

MiraLAX and Benefiber are both laxatives but work in different ways.

MiraLAX is an osmotic laxative. That means it draws water into the colon, which softens the stool and may naturally stimulate the colon to contract. These actions help ease bowel movements.

Benefiber is a wheat dextrin fiber supplement that works as a bulk-forming laxative. Like osmotic laxatives, Benefiber draws water into the colon and makes the stool softer. But in addition to that, its fiber content bulks up the stool, which naturally stimulates movement of the colon to pass the stool.

Uses

MiraLAX is used for short-term treatment of constipation and long-term treatment of chronic constipation. It’s also used for bowel prep before colonoscopy.

Benefiber is primarily used for preventing constipation. However, it may also be used for short-term treatment of constipation, as well as long-term treatment of chronic constipation.

Drug forms

MiraLAX comes as a powder in bottles and single-serve packets. You mix the powder with four to eight ounces of liquid and drink it once daily.

Benefiber comes as a bulk powder and in single-serving packets. The powder is mixed with 4 to 8 ounces of water or another non-carbonated beverage and taken 1 to 3 times daily. It can also be mixed into soft foods such as yogurt, pudding, or applesauce.

Side effects and risks

MiraLAX and Benefiber have very similar common side effects. These can include:

  • diarrhea or loose stools
  • stomach pain
  • bloating
  • gas (flatulence)
  • nausea

People with gluten intolerance may want to avoid using Benefiber. This is because Benefiber contains wheat dextrin. The manufacturer says that it contains less than 20 ppm of gluten.

Effectiveness

MiraLAX and Benefiber are both effective for treating constipation. However, no clinical studies have directly compared their effectiveness.

Guidelines from the American College of Gastroenterology and the American Society of Colon and Rectal Surgeons recommend increasing dietary fiber or using fiber supplements such as Benefiber as a first-choice treatment to prevent and treat constipation, including chronic constipation.

They also recommend osmotic laxatives such as MiraLAX for treating constipation, including chronic constipation.

Both MiraLAX and Benefiber usually take one to three days to cause a bowel movement.

MiraLAX vs. Lactulose

Both MiraLAX and lactulose are osmotic laxatives. They work by drawing water into the colon, which softens the stool and can naturally cause the colon to contract. These actions help ease bowel movements.

MiraLAX is available over-the-counter. Lactulose requires a prescription from your doctor.

Uses

MiraLAX is used for short-term treatment of constipation and long-term treatment of chronic constipation. It’s also used for bowel prep before colonoscopy.

Lactulose is used for short-term treatment of constipation and long-term treatment of chronic constipation. Lactulose is also used for people with severe liver disease who have a condition called hepatic encephalopathy.

Drug forms

MiraLAX comes as a powder in bottles and single-serve packets. You mix the powder with four to eight ounces of liquid and drink it once daily.

Lactulose comes as an oral solution and as a powder that you mix with water and drink. You take either form once daily.

Side effects and risks

MiraLAX and lactulose have very similar common side effects. These can include:

  • diarrhea or loose stools
  • stomach pain
  • bloating
  • gas (flatulence)
  • nausea

These side effects may be more common with lactulose. Lactulose may also be more likely to cause electrolyte imbalances as a result of diarrhea. Decreasing the dosage of lactulose may reduce these side effects.

Effectiveness

MiraLAX and lactulose are both effective for treating constipation. Both usually take one to three days to cause a bowel movement.

Guidelines from the American College of Gastroenterology and the American Society of Colon and Rectal Surgeons recommend osmotic laxatives such as these products for treating constipation, including chronic constipation, in adults.

An analysis of studies in children with constipation found that MiraLAX may be more effective than lactulose for increasing bowel movements.

Guidelines for treating constipation in children recommend MiraLAX as a first-choice option for short- and long-term treatment of constipation. Lactulose is considered a second-choice option.

MiraLAX vs. GoLytely

MiraLAX and GoLytely are both osmotic laxatives. That means they draw water into the colon, which softens the stool and may naturally stimulate the colon to contract. These actions help ease bowel movements.

MiraLAX and GoLytely also contain the same main ingredient, polyethylene glycol. In addition, GoLytely contains the electrolytes potassium and sodium.

MiraLAX is an over-the-counter, brand-name product. GoLytely requires a prescription from your doctor.

Uses

MiraLAX is used for short-term treatment of constipation and long-term treatment of chronic constipation. It’s also used for bowel prep before colonoscopy.

GoLytely is only used for bowel prep before colonoscopy or other procedures.

Drug forms

MiraLAX comes as a powder in bottles and single-serve packets. You mix the powder with four to eight ounces of liquid and drink it once daily when used for constipation. When used for bowel prep, larger doses are taken over a period of two days.

GoLytely comes as a powder in a large 4-liter jug. You need to add water to the jug, and then drink the solution as part of a bowel preparation procedure.

Side effects and risks

MiraLAX and GoLytely share some similar side effects, but GoLytely also has additional effects.

More common side effects

Using MiraLAX and GoLytely for bowel prep before colonoscopy or other procedures can cause similar common side effects, such as:

  • bloating
  • stomach pain
  • nausea
  • thirst

Loose stools and diarrhea are expected to occur with bowel prep procedures.

Serious side effects

Although uncommon, some serious side effects have happened in people using GoLytely bowel preparation, such as:

  • electrolyte imbalances, resulting in seizures or heart arrhythmias
  • fluid retention
  • dehydration
  • kidney problems
  • ischemic colitis (inflammation of the colon)

Other considerations

If you have certain health problems, your doctor may do special tests before prescribing GoLytely. Or, they may recommend other products. These health problems include:

  • heart arrhythmia
  • heart failure
  • seizures
  • kidney problems
  • ulcerative colitis
  • blockage in the intestine

Effectiveness

MiraLAX and GoLytely have been directly compared in clinical studies. In one study, GoLytely was more effective than MiraLAX mixed with Gatorade for bowel cleansing before colonoscopy.

In another study, a combination of MiraLAX in Gatorade plus Dulcolax worked as well as GoLytely for bowel cleansing before colonoscopy.

MiraLAX vs. Citrucel

MiraLAX and Citrucel are both laxatives but work in different ways.

MiraLAX is an osmotic laxative. That means it draws water into the colon, which softens the stool and may naturally stimulate the colon to contract. These actions help ease bowel movements.

Citrucel is a methylcellulose fiber supplement that works as a bulk-forming laxative. Like osmotic laxatives, Citrucel draws water into the colon and makes the stool softer. But in addition to that, its fiber content bulks up the stool, which naturally stimulates movement of the colon to pass the stool.

Uses

MiraLAX is used for short-term treatment of constipation and long-term treatment of chronic constipation. It’s also used for bowel prep before colonoscopy.

Citrucel is primarily used for preventing constipation. However, it may also be used for short-term treatment of constipation, as well as long-term treatment of chronic constipation.

Drug forms

MiraLAX comes as a powder in bottles and single-serve packets. You mix the powder with four to eight ounces of liquid and drink it once daily.

Citrucel is available as a bulk powder and in caplets (coated oval tablets). You mix the powder with eight ounces of liquid and drink it one to three times daily. You take the caplet one to six times daily.

Side effects and risks

MiraLAX and Citrucel have very similar common side effects. These can include:

  • diarrhea or loose stools
  • stomach pain or bloating
  • gas or flatulence
  • nausea

These side effects may decrease or go away with continued use of the products.

Taking Citrucel without adequate liquid can cause choking. Be sure to take Citrucel with at least eight ounces of liquid. If you have swallowing problems, don’t take Citrucel.

Effectiveness

MiraLAX and Citrucel are both effective for constipation. Both products usually take one to three days to cause a bowel movement.

Guidelines from the American College of Gastroenterology and the American Society of Colon and Rectal Surgeons recommend increasing dietary fiber or using fiber supplements such as Citrucel as a first-choice option to prevent and treat constipation, including chronic constipation.

The guidelines also recommend osmotic laxatives such as MiraLAX for treating constipation, including chronic constipation.

MiraLAX vs. PediaLax

MiraLAX is an osmotic laxative. That means it draws water into the colon, which softens the stool and may naturally stimulate the colon to contract. These actions help ease bowel movements.

PediaLax (magnesium hydroxide) reduces acid levels in the stomach. It also works like an osmotic laxative. It draws water into the colon, which softens the stool and can naturally stimulate the colon to contract. These effects help produce a bowel movement. (This comparison addresses only the chewable tablet form of PediaLax.)

Uses

MiraLAX is used for short-term treatment of constipation and long-term treatment of chronic constipation. It’s also used for bowel prep before colonoscopy.

MiraLAX is approved for over-the-counter use in adults and children aged 17 years and older. When recommended or prescribed by a doctor, it may also be used in younger children with ages ranging from under 2 years to 16 years.

PediaLax is used for short-term treatment of constipation. It’s not recommended for long-term treatment of chronic constipation.

PediaLax is approved for over-the-counter use in children ages 2 to 11 years.

Drug forms

MiraLAX comes as a powder in bottles and single-serve packets. You mix the powder with four to eight ounces of liquid and drink it once daily.

PediaLax comes as a chewable tablet that may be taken one to six times daily, depending on the child’s age.

Side effects and risks

Common side effects of MiraLAX include:

  • diarrhea or loose stools
  • stomach pain or bloating
  • gas or flatulence
  • nausea

PediaLax can cause the same side effects as MiraLAX, as well as:

  • cramping
  • vomiting
  • chalky taste

If your child has kidney problems, they should not use PediaLax. This product can cause high magnesium levels in the body, which can cause dangerous side effects such as:

  • muscle weakness
  • low blood pressure
  • confusion
  • heart rhythm changes

Effectiveness

MiraLAX and PediaLax are both effective for treating constipation in children. According to the North American Society of Pediatric Gastroenterology, MiraLAX is a first-choice medication for treating and preventing constipation in children.

Products that contain magnesium hydroxide, such as PediaLax, are recommended as second-choice options.

Another difference between the two products is how long they take to work. MiraLAX usually takes one to three days to cause a bowel movement. PediaLax, on the other hand, usually causes a bowel movement within 30 minutes to 6 hours.

Before giving MiraLAX or PediaLax to your child, talk with your child’s doctor. They may want to evaluate your child to determine the cause of constipation. Depending on the cause, other treatments may be needed.

If you’re taking MiraLAX to treat or prevent constipation, you should avoid drinking alcohol. Drinking alcohol, especially excessive drinking, can cause stomach problems and might worsen side effects caused by MiraLAX, such as:

  • diarrhea
  • stomach pain
  • bloating
  • dehydration
  • nausea

If you’re using MiraLAX for bowel prep before colonoscopy or another procedure, you shouldn’t drink alcohol. Bowel prep procedures usually allow drinking clear liquids but don’t allow alcoholic drinks.

MiraLAX can interact with several other medications. You may also wonder how it might interact with fiber and certain foods.

MiraLAX and other medications

Below is a list of medications that can interact with MiraLAX. This list does not contain all drugs that may interact with MiraLAX.

Different drug interactions can cause different effects. For instance, some can interfere with how well a drug works, while others can cause increased side effects.

Before taking MiraLAX, be sure to tell your doctor and pharmacist about all prescription, over-the-counter, and other drugs you take. Also tell them about any vitamins, herbs, and supplements you use. Sharing this information can help you avoid potential interactions.

If you have questions about drug interactions that may affect you, ask your doctor or pharmacist.

Diuretics

MiraLAX and other laxatives can sometimes cause electrolyte imbalances. Certain diuretics can also cause these problems. Taking laxatives with diuretics might increase the risk of serious side effects caused by electrolyte imbalances, such as muscle weakness and heart rhythm problems.

Examples of these diuretics include:

Drugs that prolong the QT interval

Certain medications prolong your QT interval, which means they might affect the rhythm of your heartbeat.

Although it’s not common, MiraLAX and other laxatives can cause electrolyte imbalances. These imbalances can increase the risk of a serious heart arrhythmia in people who have a prolonged QT interval. If you have electrolyte imbalances caused by MiraLAX or other laxatives, you should not take medications that prolong the QT interval.

Examples of these medications include:

Oral medications

You shouldn’t take oral medications (drugs you take by mouth) during the hour before you use MiraLAX for bowel prep before colonoscopy or other procedures. MiraLAX bowel prep procedures may decrease the amount of these drugs that your body absorbs.

MiraLAX and fiber

Many people take daily fiber products to prevent constipation or for general digestive health. Fiber products are usually a first choice for preventing and treating constipation.

When fiber alone isn’t enough for preventing or treating constipation, MiraLAX may be taken along with it until constipation goes away.

MiraLAX and foods

MiraLAX powder should be added to four to eight ounces of water or other liquids. These other liquids can include milk or coffee.

MiraLAX and milk

MiraLAX can be mixed with and consumed in milk. Be sure to mix it with at least four to eight ounces of milk.

MiraLAX in coffee

MiraLAX can be mixed with and consumed in coffee. Be sure to mix it with at least four to eight ounces of coffee.

Here are answers to some common questions about MiraLAX.

Is MiraLAX a stool softener?

MiraLAX is classified as an osmotic laxative, not a stool softener. However, both products do soften the stool. Osmotic laxatives do this by drawing water into the colon (large intestine). Stool softeners do it by drawing water into the stool itself.

Is MiraLAX a laxative?

Yes, MiraLAX is a laxative. It’s called an osmotic laxative. This means it works by drawing water into the colon. The water softens the stool and may naturally stimulate the colon to contract. These actions help ease bowel movements.

MiraLAX is not a stimulant laxative.

Is MiraLAX fiber?

No, MiraLAX is not fiber.

Can I take MiraLAX with fiber?

Yes, you can take MiraLAX with fiber. Many people take fiber daily to prevent constipation and for general digestive health. Fiber products are usually a first choice for preventing and treating constipation.

When fiber isn’t enough for preventing or treating constipation, MiraLAX may also be taken until constipation goes away.

How fast does MiraLAX work?

MiraLAX usually causes a bowel movement within one to three days.

Is it safe to use MiraLAX long-term?

Over-the-counter MiraLAX and other laxatives are usually only recommended for short-term use, up to a week.

If your constipation lasts longer than a week, you should see your doctor. Your doctor may want to evaluate the cause of your constipation. Depending on the cause, your doctor may recommend long-term use of MiraLAX or other treatments.

Does MiraLAX come in a prescription form?

MiraLAX is not available in prescription form. Similar products such as GoLytely are available by prescription from a doctor.

Is MiraLAX safe for use after surgery?

MiraLAX is sometimes used after surgery to prevent and treat constipation. However, if you’ve had surgery and are having constipation, talk with your doctor. Your doctor may want to evaluate the cause of your symptoms. Depending on the cause, your doctor may recommend MiraLAX or other treatments.

Taking too much MiraLAX can increase your risk of side effects.

Overdose symptoms

Symptoms of an overdose can include:

  • bloating
  • stomach pain
  • nausea
  • excessive diarrhea
  • dehydration
  • electrolyte imbalances
  • thirst

What to do in case of overdose

If you think you’ve taken too much of this drug, call your doctor or seek guidance from the American Association of Poison Control Centers at 800-222-1222 or through their online tool. But if your symptoms are severe, call 911 or go to the nearest emergency room right away.

Before taking MiraLAX, talk with your doctor about your health history. MiraLAX may not be appropriate for you if you have certain medical conditions.

  • For people with kidney disease: Although it’s not common, MiraLAX and other laxatives can cause electrolyte imbalances. This problem can be worse in people with kidney disease. If you have kidney disease, talk with your doctor before using MiraLAX or other laxatives.
  • For people with stomach problems: If you have stomach problems such as nausea, vomiting, bloating, or stomach pain, talk with your doctor before using MiraLAX or other laxatives. Your doctor may need to evaluate the cause of your symptoms to see if MiraLAX or other laxatives are safe for you.
  • For people with irritable bowel syndrome (IBS): MiraLAX and other laxatives may worsen some symptoms of IBS. If you have IBS, talk with your doctor before taking MiraLAX or other laxatives.
  • For people with swallowing problems: MiraLAX may cause choking when used by people with swallowing problems. If you have swallowing problems, talk with your doctor before using MiraLAX.

Each MiraLAX package is given an expiration date by the manufacturer of the product. This date is printed on the package. The purpose of the expiration date is to guarantee the effectiveness of the medication during this time.

The current stance of the Food and Drug Administration (FDA) is to avoid using expired medications. However, an FDA study showed that many medications may still be good beyond the expiration date listed on the bottle.

How long a medication remains good can depend on many factors, including how and where the medication is stored. MiraLAX should be stored at room temperature in its original container.

If you have unused medication that has gone past the expiration date, talk to your pharmacist about whether you might still be able to use it.

The following information is provided for clinicians and other healthcare professionals.

Mechanism of action

MiraLAX is an osmotic laxative. In the gastrointestinal tract, it retains water in the colon and within the stool. The increased water in the colon may also naturally stimulate contraction. MiraLAX increases stool weight, softens the stool, and increases stool frequency.

Pharmacokinetics and metabolism

When taken orally, less than 0.2 percent of MiraLAX is absorbed through the gastrointestinal tract. The remainder of the oral dose is recovered in the stool. MiraLAX is not fermented or metabolized in the gastrointestinal tract.

Contraindications

MiraLAX is contraindicated in patients with:

  • known or suspected gastrointestinal obstruction
  • known hypersensitivity to polyethylene glycol

Storage

MiraLAX should be stored at room temperature, 68 degrees F to 77 degrees F, in its original container.

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up-to-date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.