What to Know About Prescription Laxatives

If you're constipated and an over-the-counter (OTC) laxative isn't doing the trick, you may need to talk to your healthcare provider about a prescription laxative.

OTC products—especially stimulant laxatives—are meant for very short-term use only, and over-using them could make your constipation worse and lead to very serious medical problems. They can even be addictive.

Also, constipation that won't clear up may be a symptom of a serious illness, so you have plenty of reason to see your healthcare provider.

Using prescription laxatives under a healthcare provider's supervision is much safer for long-term use, so if you have regular constipation, this may be a better option for you. Several types are on the market that work differently, so if one type doesn't work for you, another might.

Uses

Prescription laxatives are most often prescribed for treating:

• Chronic constipation that's idiopathic (not due to any known cause)
• Constipation related to a condition, including that from constipation-predominant irritable bowel syndrome (IBS-C)
• Opioid-induced constipation

Unlike OTC laxatives, prescription drugs aren't meant for rapid relief of occasional constipation, but rather to keep you regular when constipation is an ongoing problem.

Medications Available

Four classes of prescription laxatives are on the market. Each one works differently and may be prescribed in different situations, depending on what's believed to be causing your constipation. They are:

• Osmotic agents
• Prokinetic agents
• Secretagogues
• Opioid antagonists

Osmotic Agents

Available in both OTC and prescription products, osmotic laxatives draw water into the bowel to help soften your stool so it passes more easily.

Osmotics that are available OTC and by prescription include:

• Polyethylene glycol (PEG) 3350: Approved for occasional constipation. Brand names include Miralax, GlycoLax, Healthylax, Smooth LAX, Vita Health.
• Sorbitol: Approved for occasional constipation and irregularity. Brand names include Arlex.

Prescription-only osmotics include:

• Cholac/Generlac (lactulose): Approved for constipation, including that related to barium retention
• Pizensy (lactitol): Approved for chronic idiopathic constipation in adults

Prokinetic Agents

Prokinetic agents cause your gastrointestinal tract to contract and push materials through. The only drug in this class that's currently available in the United States is:

• Motegrity (prucalopride): Approved for chronic idiopathic constipation in adults

This drug is marketed in other countries under the brand name Resolor. It's also classified as a serotonin receptor agonist.

The similar drug Zelnorm (tegaserod) was withdrawn from the U.S. market in 2007 due to serious cardiovascular side effects; however, Motegrity is not associated with this risk.

Secretagogues

Secretagogues pull more water into the bowel to soften the stool, like osmotics, but through a different mechanism of action. Drugs in this class include:

• Amitiza (lubiprostone): Approved for chronic constipation in adults and constipation from IBS-C in adult women
• Linzess (linaclotide): Approved for chronic constipation, including that from IBS-C, in adults
• Trulance (plecantide): Approved for chronic constipation in adults

Opioid Antagonists

Opioid painkillers frequently cause constipation. Several medications have been developed to relieve this type of constipation by partially blocking the actions of opioid medications. They include:

• Relistor (methylnaltrexone): Approved for opioid-induced constipation (OIC) in adults with non-cancer pain (an injectable form is available for adults in palliative care)
• Movantik (naloxegol): Approved for opioid-induced constipation in adults with non-cancer pain
• Symproic (naldemedine): Approved for opioid-induced constipation in adults with non-cancer pain

Before Taking

You may want to try lifestyle remedies before turning to laxatives for constipation. These include:

• Exercising regularly
• Drinking more water
• Increasing dietary fiber
• Not holding in bowel movements

You shouldn't use OTC laxatives for more than a week without talking to your healthcare provider. Prescription medications are considered safer for long-term use.

When you go to the healthcare provider for constipation, expect them to ask about your:

• Medical history, including medications, medical conditions, previous surgeries, diet, and physical activity
• Symptoms, including those that may indicate a medical condition such as IBS, pelvic floor dysfunction, or colon cancer
• Stool, including appearance, shape, and consistency

In addition to checking your vital signs and weight, a physical exam for constipation may include:

• Pressing on your abdomen to evaluate pain, swelling, and any lumps or masses
• Listening to your intestinal sounds with a stethoscope
• Examining your rectum for abnormalities
• Checking anal wink reflexes
• A digital rectal exam

Your healthcare provider may also order blood tests and imaging studies. A colonoscopy is less common but it may be ordered if certain symptoms are present.

Contraindications

Not all prescription laxatives are safe for everyone. Some medical conditions or other circumstances may make a drug unsuitable for you. These are called contraindications.

GI Problems

If you have a known or suspected intestinal obstruction, your healthcare provider will likely not prescribe any of these drugs for you:

• Amitiza
• Linzess
• Motegrity
• Movantik
• PEG
• Pizensy
• Relistor
• Symproic
• Trulance

GI problems including obstructions, perforations, Crohn's disease, Hirschsprung's disease, ulcerative colitis, toxic megacolon/megarectum, irritable bowel syndrome, gut wall disorders, and obstructive ileus are contraindications for:

• Motegrity
• PEG

Kidney Function

Special consideration should be taken for people with impaired kidney function when it comes to:

• Movantik (lower dosage required)
• PEG (used only under a healthcare provider's supervision)
• Relistor (lower dosage required)

Dietary Issues

If you have diabetes, caution is urged due to the sugar content of:

• Cholac/Generlac

Galactosemia is a condition requiring a special diet that's low in galactose. These laxatives contain galactose:

• Cholac/Generlac
• Pizensy (lactitol)

If you have fructose intolerance, you should avoid:

• Sorbitol

Special Populations

Some prescription laxatives require special monitoring or altered dosages in geriatric (older) people. Your healthcare provider can help guide you to the safest drug for you based on your complete medical history.

Most prescription laxatives are minimally absorbed by the bloodstream, meaning they're considered safe during pregnancy and breastfeeding. However, for the safety of your child, you should check with your healthcare provider about any drugs you're considering.

Other

If you're having surgery, you should avoid Cholac/Generlac beforehand.

If you take a strong CYP3A4 inhibitor drug (such as clarithromycin or ketoconazole), you shouldn't take Movantik. Symproic may interact negatively with these medications as well.

If you have anuria (failure of kidneys to produce urine), you shouldn't take sorbitol.

Side Effects and Warnings

Each class of laxatives is associated with certain side effects and warnings. Individual medications may have some or all of those listed here and may also be associated with others; be sure you're familiar with all the possible risks of any medication you're taking.

Osmotics

Common side effects of osmotic laxatives include:

• Nausea
• Bloating
• Cramping
• Flatulence
• Diarrhea

Potentially serious side effects include:

• Dehydration
• Electrolyte imbalance

Prokinetics

Common side effects of Motegrity include:

• Headache
• Abdominal pain
• Nausea
• Diarrhea
• Abdominal distention
• Dizziness
• Vomiting
• Flatulence
• Fatigue

Motegrity comes with a warning about worsening depression and the emergence of suicidal thoughts and behaviors. You should stop taking this medication right away and contact your healthcare provider if you experience this.

Secretagogues

Common side effects of secretagogues include:

• Diarrhea, which may be severe
• Nausea
• Headache
• Abdominal pain and distention
• Flatulence

Opioid Antagonists

Common side effects of opioid antagonists include:  

• Abdominal pain
• Diarrhea
• Nausea
• Headache
• Flatulence
• Vomiting

These drugs also carry warnings about the possibility of gastrointestinal perforation in people with known or suspected lesions in the GI tract.

A Word From Verywell

Because it could be a symptom of a more serious problem, be sure to let your healthcare provider know about your constipation, especially if it lasts more than a few days or returns frequently.

You don't have to suffer from constipation. If you have regular or long-lasting bouts, prescription laxatives may be a safer and more effective option for you than over-the-counter medications.