Movantik vs Miralax

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For patients dealing with constipation, particularly opioid-induced constipation (OIC), certain drugs that influence the functioning of gastrointestinal tract can help in managing symptoms. Movantik and Miralax are two such medications frequently prescribed for this purpose. They each impact different processes within the digestive system but both aid in relieving constipation. Movantik is a peripherally acting mu-opioid receptor antagonist (PAMORA) that specifically targets opioid receptors in the gut without affecting those in the brain, thereby reducing OIC while preserving pain relief from opioids. On the other hand, Miralax works by increasing water retention in the colon to soften stools and increase bowel movements, making it more suitable for general forms of constipation rather than OIC specifically.

What is Movantik?

Naloxegol (the generic name for Movantik) was a significant advancement in the class of drugs known as peripherally-acting mu-opioid receptor antagonists (PAMORAs). Naloxegol was first approved by the FDA in 2014. It is designed to counteract opioid-induced constipation by blocking the binding of opioids to peripheral receptors in the gastrointestinal tract, thus increasing bowel movements. Movantik specifically acts on these peripheral receptors without influencing central nervous system activity.

On the other hand, Polyethylene Glycol 3350 (commonly known as Miralax), which has been available over-the-counter since 1999, works differently. This osmotic laxative draws water into your colon from surrounding body tissues to allow for easier bowel movements. Unlike Movantik that specifically targets opioid-induced constipation, Miralax can be used more broadly for occasional constipation and irregularity.

Movantik's specific action results in it having fewer side effects compared to general osmotic laxatives like Miralax that work throughout your digestive tract.

What conditions is Movantik approved to treat?

Movantik is approved for the treatment of opioid-induced constipation in adults with chronic non-cancer pain, including patients with chronic pain related to prior cancer or its treatment who do not require frequent (e.g., weekly) opioid dosage escalation:

  • Opioid-induced constipation
  • Chronic non-cancer pain

Meanwhile, Miralax is primarily used as a laxative to treat occasional constipation or irregular bowel movements:

  • Occasional Constipation
  • Irregular bowel movements.

How does Movantik help with these illnesses?

Movantik functions to alleviate opioid-induced constipation by blocking the effects of opioids on mu-receptors in the gut. Opioids are known to reduce gastric motility and increase absorption of water from feces, leading to constipation. Movantik acts as a peripherally acting mu-opioid receptor antagonist (PAMORA). In simple terms, it blocks the action of opioids specifically at receptors located in your gastrointestinal tract without affecting their pain-relieving properties elsewhere in your body.

On the other hand, Miralax works differently; it's an osmotic laxative that draws water into your intestines which helps soften stools and stimulate bowel movements. It does not directly interact with opioid receptors or any specific neurotransmitters but rather relies on physicochemical properties to retain more fluid within the stool.

Both these drugs aim for improving bowel habits but through different mechanisms - while Movantik counteracts negative effects of opioids on bowels, Miralax simply increases the water content in stool making them easier to pass.

What is Miralax?

Miralax, also known by its generic name polyethylene glycol 3350, is an osmotic laxative that increases the water content in your intestines to stimulate bowel movements. It was first approved by the FDA in 1999 and can be purchased over-the-counter without a prescription. Unlike Movantik which specifically targets opioid-induced constipation, Miralax has a broader application as it aids general constipation regardless of cause. Miralax works differently from stimulant-type laxatives, as it does not cause contraction of intestinal muscles to move stool along. Instead, it functions by retaining water in the stool to soften it and increase its size, which triggers natural contractions of your intestines. The side-effect profile for Miralax typically includes bloating or feelings of fullness, gas or mild diarrhea but lacks severe adverse effects such as dependency risk seen with other types of laxatives like stimulants.

What conditions is Miralax approved to treat?

Miralax is approved for the treatment of occasional constipation. It works by bringing water into your bowels, which helps to soften stools and increase the frequency of bowel movements. Conditions that Miralax effectively addresses include:

  • Chronic or occasional constipation
  • Irregular bowel movements

How does Miralax help with these illnesses?

Miralax is a type of medication known as an osmotic laxative, and plays roles in many processes within the digestive system. It works by retaining water in the stool to soften it and increase bowel movements, thus alleviating constipation symptoms. Its effects on electrolyte levels and hydration may also influence its role as a laxative. Miralax does not directly affect opioid receptors like Movantik does, which makes it suitable for general use when patients are suffering from occasional constipation. Since it doesn't interact with opioid receptors, Miralax can be used safely by those who are not taking opioids or have chronic idiopathic constipation (CIC), whereas Movantik is specifically designed for people with Opioid-Induced Constipation (OIC).

How effective are both Movantik and Miralax?

Both naloxegol (Movantik) and polyethylene glycol 3350 (Miralax) are approved by the FDA for treating constipation, but they were developed to address different types of this condition and work in distinct ways. Naloxegol is specifically designed for opioid-induced constipation in adults with chronic non-cancer pain, whereas Miralax is an osmotic laxative used to treat occasional constipation.

The effectiveness of Movantik and Miralax was directly studied in separate clinical trials; both drugs exhibited efficacy in managing symptoms of constipation with promising safety profiles. Movantik works by blocking the effect of opioids on the gut without affecting pain relief provided by these drugs, while Miralax works by drawing water into the colon which helps increase bowel frequency.

A review indicated that Movantik starts working within a few hours after intake and its maximal effect occurs around 12 hours post-dose. Its most common side effects include abdominal pain, diarrhea, nausea, flatulence and vomiting. It's also important to note that patients should not take certain medications like grapefruit juice or St John’s Wort while using Movantik as these can affect how it works.

On the other hand, a study reported that Miralax usually produces a bowel movement within one to three days of starting treatment. The same study reports that it has minimal side effects due to very limited systemic absorption but sometimes may cause bloating, gas or feeling full or stuffed.

In summary: While both medicines are effective at treating constipation symptoms; their choice depends largely on what type of condition you're trying to treat - if you have opioid-induced constipation then consider naloxegol otherwise polyethylene glycol would be more appropriate for regular cases of occasional constipation.

abstract image of a researcher studying a bottle of drug.

At what dose is Movantik typically prescribed?

Dosage for Movantik usually starts at 25 mg once daily, taken orally. If side effects become bothersome, the dose can be reduced to 12.5 mg per day. For individuals with severe kidney problems or those taking certain other medications, starting with a lower dose of 12.5 mg is recommended. On the other hand, Miralax dosages typically involve one capful (17 grams) dissolved in four to eight ounces of beverage and consumed once daily as needed for constipation relief. Always consult your healthcare provider before making any changes to medication use or dosage.

At what dose is Miralax typically prescribed?

Miralax treatment usually begins with a dose of 17 grams (about one heaping tablespoon) per day. This can be mixed into any beverage, such as water or juice, and should be consumed immediately after mixing. The dosage may then be adjusted according to the response to treatment and individual patient needs but should not exceed once daily dosing. For some patients, the effects are noticed within just one to three days of starting treatment. However, it's important to continue taking Miralax even if there is no immediate response - full benefits are often seen only after a couple weeks of consistent use.

What are the most common side effects for Movantik?

Common side effects of Movantik may include:

  • Abdominal pain and discomfort
  • Nausea
  • Diarrhea
  • Excessive gas in stomach or intestines
  • Headache
  • Vomiting

In contrast, Miralax may have these common side effects:

  • Bloated or full feeling
  • Increased bowel movements, diarrhea
  • Nausea or upset stomach -Stomach cramps

These are not all the possible side effects of these drugs. It's important to consult with a healthcare provider for detailed information.

abstract image of a patient experiencing side effect

Are there any potential serious side effects for Movantik?

While taking Movantik, it's important to monitor for potential serious side effects which may include:

  • Severe stomach pain or diarrhea
  • Signs of allergic reactions: hives, difficulty breathing, swelling in your face or throat
  • Opioid withdrawal symptoms: anxiety, irritability, sweating, fever, chills
  • Unusual tiredness or weakness

In rare cases individuals have experienced more severe symptoms such as:

  • Fast or irregular heartbeat
  • Symptoms of dehydration (e.g., dry mouth/throat/eyes), decreased urination
  • Loss of appetite due to changes in taste

If you experience any of these symptoms while taking Movantik please reach out to a healthcare professional immediately. It's important not to confuse the normal functioning of this medication (which is designed to alleviate constipation) with potentially harmful side effects.

What are the most common side effects for Miralax?

Miralax, while generally well-tolerated, can lead to some side effects such as:

  • Bloating
  • Gas or mild stomach upset
  • Diarrhea
  • Nausea or vomiting
  • Stomach cramps In rare cases, it may cause an allergic reaction that could manifest as a rash. It is essential to note that these side effects are relatively uncommon and the majority of users tolerate Miralax without significant discomfort. However, if you experience severe or persistent symptoms after taking this medication, please consult your healthcare provider promptly.

Are there any potential serious side effects for Miralax?

Miralax is a commonly used over-the-counter medication for constipation relief. However, like any drug, it can also cause adverse effects in certain situations:

  • Signs of allergic reactions such as skin rash, itching or hives; swelling of the face, lips or tongue
  • Breathing problems
  • Feeling faint or lightheaded
  • Changes in mood or emotions
  • Unusual bloating or abdominal pain
  • Diarrhea with unusual color and odor

It's important to contact your healthcare provider right away if you experience these symptoms after taking Miralax. While these side effects are rare, they may indicate a more serious issue that requires immediate medical attention.

Contraindications for Movantik and Miralax?

Both Movantik and Miralax, along with most other laxative medications, may exacerbate symptoms in some individuals. If you notice your condition worsening or an increase in abdominal pain or discomfort, seek immediate medical attention.

Neither Movantik nor Miralax should be taken if you are currently taking, or have recently been on a regimen of certain types of medications like opioids without consulting your doctor. Always inform your healthcare provider about any medicines you're taking; this is particularly important for those on opioid medication due to potential interactions with Movantik that can cause opioid withdrawal symptoms.

Movantik requires caution when used by people who have stomach problems such as gastric retention or perforation risk. Similarly, care must be taken when using Miralax if you have kidney disease or electrolyte imbalance issues. In all cases it's crucial to discuss these concerns with your physician before starting either drug.

How much do Movantik and Miralax cost?

For the brand-name versions of these drugs:

  • The price for a month supply (30 tablets) of Movantik (25 mg) averages around $380, which works out to about $12.67/day.
  • The price for 30 doses of Miralax (17 g each), averages around $20, working out to approximately $0.67/day.

Thus, if you are using the maximum recommended dose for each product daily, then brand-name Miralax is significantly less expensive on a per-day treatment basis compared to Movantik. However, please remember that cost should not be your primary consideration in determining which of these medications is right for you.

In terms of generic versions:

  • There's currently no generic version available for Movantik.
  • For polyethylene glycol 3350 - the active ingredient in Miralax - costs are lower than its branded counterpart with prices ranging from as low as about $10-$15 per bottle equivalent to a month’s supply ($0.33–$0.50/day).

Popularity of Movantik and Miralax

Naloxegol, available under the brand name Movantik, is a peripherally acting mu-opioid receptor antagonist (PAMORA) used to treat opioid-induced constipation. It was prescribed to about 1.7 million people in the United States in 2020. This accounted for approximately 15% of all prescriptions for PAMORAs during that year.

Polyethylene glycol 3350 or PEG 3350, known by its brand name Miralax among others, is an osmotic laxative which increases the amount of water in the gut and has been commonly used as a first-line treatment for occasional constipation. In contrast to Movantik's usage trend, Miralax was prescribed to an estimated whopping figure of around 20 million people in USA in 2020 alone thus making it one of most popular over-the-counter remedies against constipation.


Both Movantik (naloxegol) and Miralax (polyethylene glycol 3350) have been proven to be effective in managing constipation, particularly opioid-induced constipation. They function differently, with Movantik specifically designed to counteract the constipating effects of opioids on the gut, while Miralax works by drawing water into the intestines to soften stools.

Movantik is a prescription medication often used when over-the-counter laxatives like Miralax are not effective enough. It's usually considered as an option for patients who are taking opioids for non-cancer related pain and suffering from opioid-induced constipation.

Miralax is generally available without a prescription and can be used by most adults and children above 17 years old. It's typically recommended as first-line therapy for occasional bouts of constipation due to its gentle mechanism of action.

While both medications have good safety profiles, they do come with possible side effects such as bloating or diarrhea. Movantik may also cause withdrawal symptoms in people dependent on opioids; hence it should only be taken under close medical supervision. As always, it's essential that patients discuss their symptoms thoroughly with a healthcare professional before starting any new medication regimen.