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NALDEMEDINE

Naldemedine is a medication being studied as a treatment for opioid-induced constipation (OIC), a common side effect experienced by patients taking opioid medications for pain management. As a peripherally acting μ-opioid receptor antagonist (PAMORA), naldemedine works by blocking opioid receptors in the gastrointestinal tract without affecting pain relief. Clinical trials are investigating the safety and effectiveness of naldemedine across different patient populations, including adults with chronic non-cancer pain, cancer patients, and even children. This article explores the current research on naldemedine and what it may mean for patients suffering from opioid-related digestive issues.

Table of Contents

What is Naldemedine?

Naldemedine (also known by the brand names Symproic® and Rizmoic) is a medication specifically designed to treat opioid-induced constipation (OIC) in adults with chronic pain[1]. It belongs to a class of drugs called peripherally acting mu-opioid receptor antagonists (PAMORAs). Unlike regular laxatives, naldemedine works directly on the cause of constipation that happens when patients take opioid pain medications[2].

Naldemedine is typically available as a 0.2 mg tablet that is taken once daily with or without food[3]. For children, it may also be available as an oral suspension, which makes it easier to administer to younger patients[4].

How Naldemedine Works

To understand how naldemedine works, it’s important to first understand why opioid medications cause constipation. Opioids relieve pain by binding to receptors called mu-opioid receptors in the brain. However, these same receptors are also found throughout your digestive system. When opioids bind to these receptors in your gut, they slow down the natural movement of your intestines, reducing water secretion and making bowel movements difficult[5].

Naldemedine specifically targets and blocks these mu-opioid receptors in your digestive tract, but an important feature is that it does not cross the blood-brain barrier. This means it works only in your gut and does not interfere with the pain-relieving effects of your opioid medication in your brain[6]. By blocking the opioid receptors in your gut, naldemedine helps restore normal bowel function while allowing your pain medication to continue working effectively.

Understanding Opioid-Induced Constipation

Opioid-induced constipation (OIC) is a common side effect experienced by up to 90% of patients taking opioid medications for pain management[6]. Unlike regular constipation, OIC occurs specifically because of how opioids affect your digestive system and often doesn’t respond well to standard laxative treatments.

Common symptoms of OIC include:

  • Reduced frequency of bowel movements
  • Hard, dry stools that are difficult to pass
  • Straining during bowel movements
  • Incomplete evacuation (feeling like you haven’t completely emptied your bowels)
  • Abdominal bloating and discomfort
  • Abdominal pain

OIC can significantly impact quality of life and may even cause some patients to reduce or stop their pain medication, which can lead to inadequate pain control[2]. This is why treatments specifically targeting OIC, like naldemedine, are important for patients requiring long-term opioid therapy.

Benefits of Naldemedine

Clinical studies have shown several benefits of naldemedine for patients with opioid-induced constipation:

  • Increased frequency of bowel movements: Research shows that naldemedine significantly increases the number of spontaneous bowel movements (bowel movements that occur without the use of rescue laxatives) per week compared to placebo[2].
  • Faster relief: Studies indicate that many patients experience their first spontaneous bowel movement within 24-48 hours after starting treatment with naldemedine[5].
  • Improved stool consistency: Naldemedine helps improve stool consistency, making bowel movements easier to pass[7].
  • Reduced straining: Patients taking naldemedine report less straining during bowel movements[8].
  • Better quality of life: By reducing constipation symptoms, naldemedine helps improve overall quality of life for patients on long-term opioid therapy[1].
  • Maintains pain relief: Because naldemedine doesn’t cross into the brain, it doesn’t interfere with the pain-relieving effects of opioid medications[6].

Dosage and Administration

For adults with chronic non-cancer pain, the standard recommended dose of naldemedine is 0.2 mg taken orally once daily with or without food[3]. The medication can be taken at any time of day, but taking it at the same time each day helps establish a routine.

For children, dosing is weight-based and may range from 0.05 mg to 0.2 mg. In pediatric patients, naldemedine may be administered either as tablets (for the 0.2 mg dose level only) or as an oral suspension (for all dose levels)[4].

Important administration points:

  • Naldemedine can be taken with or without food
  • If you miss a dose, take it as soon as you remember. If it’s almost time for your next dose, skip the missed dose and continue with your regular schedule
  • Do not take more than one dose in a 24-hour period
  • Tablets should be swallowed whole and not crushed or chewed
  • For patients who have difficulty swallowing tablets, an oral suspension may be available through your healthcare provider

Clinical Research on Naldemedine

Naldemedine has been extensively studied in multiple clinical trials to evaluate its efficacy and safety for treating opioid-induced constipation.

Short-Term Efficacy Studies

Several 12-week studies have demonstrated that naldemedine significantly improves bowel function in patients with OIC. In these studies, participants receiving naldemedine were more likely to have regular, spontaneous bowel movements compared to those receiving placebo[8]. The studies measured what’s called a “responder,” defined as a person who had at least 3 spontaneous bowel movements per week and an increase of at least 1 spontaneous bowel movement from their baseline[2].

Long-Term Safety Studies

A 52-week study evaluated the long-term safety of naldemedine. This study showed that naldemedine maintained its effectiveness over the extended period and did not lead to significant withdrawal symptoms or loss of pain control in patients taking opioids[1]. Importantly, the long-term use of naldemedine continued to show improvements in quality of life measurements related to constipation symptoms[1].

Dose-Finding Studies

Early research on naldemedine tested various doses ranging from 0.1 mg to 0.4 mg. These studies helped determine that the 0.2 mg dose provides the optimal balance of efficacy and safety for most patients[7]. Lower doses (0.1 mg) showed less efficacy, while higher doses (0.4 mg) did not provide significant additional benefits but had a slightly higher rate of side effects[7].

Research on Special Uses

Beyond treating OIC, naldemedine is being studied for other potential uses. For example, one study is investigating naldemedine’s effects on gastrointestinal recovery following surgeries that include bowel resection or transection[9]. Another study is exploring whether naldemedine can help prevent opioid-induced nausea and vomiting in patients with cancer starting opioid analgesics[10]. Additional research is examining its potential benefits in recurrent acute pancreatitis[11].

Safety Profile and Side Effects

Clinical trials have shown that naldemedine is generally well-tolerated, but like all medications, it can cause side effects in some patients.

Common Side Effects

The most common side effects reported in clinical trials include[1]:

  • Abdominal pain: This is typically mild to moderate and tends to decrease over time as your body adjusts to the medication
  • Diarrhea: Some patients experience loose stools, especially when first starting treatment
  • Nausea: Feelings of queasiness may occur, particularly during the initial days of treatment
  • Vomiting: Less common than nausea but can occur in some patients
  • Gastroenteritis: Inflammation of the stomach and intestines causing discomfort

Most of these side effects are mild to moderate and often improve after the first week of treatment as your body adjusts to the medication[1].

Serious Side Effects

Though rare, more serious side effects can occur and require immediate medical attention[5]:

  • Opioid withdrawal symptoms: Though uncommon since naldemedine doesn’t cross the blood-brain barrier, some patients may experience symptoms like sweating, chills, diarrhea, stomach pain, anxiety, irritability, and yawning
  • Gastrointestinal perforation: Very rare but serious, this is more likely in patients with certain gastrointestinal conditions or taking medications that may increase the risk

Drug Interactions

Naldemedine may interact with certain medications[7]:

  • Strong CYP3A inhibitors (like clarithromycin, ketoconazole, or grapefruit juice): These may increase naldemedine levels in your body
  • Strong CYP3A inducers (like rifampin, carbamazepine, or St. John’s wort): These may decrease naldemedine levels and make it less effective
  • P-glycoprotein inhibitors (like cyclosporine): These may increase naldemedine exposure

Always inform your healthcare provider about all medications, supplements, and herbal products you are taking before starting naldemedine.

Naldemedine in Special Populations

Pediatric Patients

Research on naldemedine use in children is ongoing. A current clinical trial is evaluating the pharmacokinetics, safety, and tolerability of naldemedine in pediatric patients who are receiving opioids[4]. This study involves different age cohorts, starting with adolescents (≥12 to <18 years) and progressively including younger children (≥6 to <12 years, and then ≥2 to <6 years) as safety is established. For children, the medication may be administered as an oral tablet (0.2 mg dose level only) or as an oral suspension (all dose levels)[4].

Elderly Patients

Clinical studies have included patients over 65 years of age, and no dose adjustment is generally necessary for elderly patients based solely on age. However, as kidney and liver function may decline with age, monitoring for side effects may be more important in this population[1].

Patients with Liver or Kidney Impairment

For patients with mild to moderate liver impairment, no dose adjustment is typically required. However, naldemedine has not been extensively studied in patients with severe liver impairment. Similarly, patients with mild to moderate kidney impairment usually don’t need dose adjustments, but those with severe kidney impairment should be monitored more closely[1].

Naldemedine Compared to Other Medications

Several medications are available to treat opioid-induced constipation. Understanding how naldemedine compares to these alternatives can help patients and healthcare providers make informed decisions.

Comparison with Other PAMORAs

Naldemedine belongs to the same class of medications (PAMORAs) as naloxegol (Movantik®) and methylnaltrexone (Relistor®). All three work by blocking opioid receptors in the gut without affecting pain relief. Some differences include:

  • Administration: Naldemedine and naloxegol are taken orally once daily, while methylnaltrexone may be given as an injection or oral tablet
  • Food interactions: Naldemedine can be taken with or without food, while naloxegol should be taken on an empty stomach
  • Cardiovascular safety: A study is currently investigating the comparative cardiovascular safety of naldemedine versus other OIC medications[3]

Comparison with Traditional Laxatives

Unlike traditional laxatives (such as stimulant laxatives, stool softeners, or osmotic agents), naldemedine addresses the specific mechanism of opioid-induced constipation by targeting opioid receptors in the gut. Traditional laxatives work through different mechanisms:

  • Stimulant laxatives (like bisacodyl): Increase intestinal contractions
  • Stool softeners (like docusate): Make stool softer by increasing water content
  • Osmotic laxatives (like polyethylene glycol): Draw water into the intestine
  • Bulk-forming laxatives (like psyllium): Add bulk to stool to stimulate bowel movements

While traditional laxatives may provide some relief, they often don’t fully address OIC because they don’t target the underlying mechanism. Naldemedine may be more effective for OIC because it specifically blocks the effects of opioids on the gut[2].

Studies have shown that many patients with OIC continue to experience constipation despite using traditional laxatives, suggesting that medications like naldemedine may provide better relief for these patients[8].

Future Research Directions

Research on naldemedine continues to explore its potential benefits beyond treating OIC in patients with chronic non-cancer pain.

Expanded Applications

Several ongoing and planned studies are investigating naldemedine for:

  • Postoperative gastrointestinal recovery: A study is examining whether naldemedine can improve recovery of gastrointestinal function following surgeries involving bowel resection or transection[9]
  • Opioid-induced nausea and vomiting: Research is exploring whether naldemedine can help prevent opioid-induced nausea and vomiting in patients starting opioid analgesics for cancer pain[10]
  • Pediatric populations: Studies are ongoing to establish safety, efficacy, and appropriate dosing for children who require opioid therapy[4]
  • Recurrent acute pancreatitis: Investigation into whether naldemedine can reduce disease recurrence and progression in patients with recurrent acute pancreatitis[11]
  • Opioid-induced bowel dysfunction: Beyond constipation, research is looking at how naldemedine affects the broader spectrum of gastrointestinal issues caused by opioids[6]

Long-term Outcomes

Future research will likely continue to evaluate the long-term safety and efficacy of naldemedine, particularly focusing on:

  • Long-term impact on quality of life for patients requiring chronic opioid therapy
  • Potential effects on opioid dosing requirements and pain management
  • Safety outcomes with extended use beyond the current studies of up to 52 weeks
  • Comparative effectiveness against other PAMORAs and traditional laxatives

As research continues, our understanding of how best to use naldemedine will continue to evolve, potentially offering more patients relief from the challenging side effects of opioid therapy while maintaining effective pain control.

Study Feature Details
Patient Populations – Adults with non-malignant chronic pain receiving opioid therapy
– Pediatric patients (ages 2 to <18 years) receiving opioids
– Patients with cancer starting opioid analgesics
– Patients undergoing bowel surgery
– Patients with recurrent acute pancreatitis
Dosing Regimens – Standard adult dose: 0.2 mg once daily
– Alternative adult doses tested: 0.01 mg, 0.03 mg, 0.1 mg, 0.3 mg, 0.4 mg, 1 mg, 3 mg
– Pediatric doses: 0.05 mg to 0.2 mg based on body weight
– Postoperative setting: 1.25 mg, 2.5 mg, or 5 mg twice daily
Administration Forms – Oral tablets
– Oral suspension (especially for pediatric patients)
– Oral solution (for very low doses)
Primary Efficacy Outcomes – Changes in spontaneous bowel movement (SBM) frequency
– Response rate (patients achieving ≥3 SBMs per week and ≥1 increase from baseline)
– Time to first bowel movement after dosing
– Changes in complete spontaneous bowel movement (CSBM) frequency
Secondary Outcomes – Stool consistency (Bristol Stool Scale)
– Straining during bowel movements
– Abdominal symptoms (bloating, discomfort)
– Quality of life measures
– Rescue medication use
– Patient global satisfaction
Safety Assessments – Adverse events monitoring
– Opioid withdrawal symptoms using COWS and WOWS scales
– Cardiovascular safety (MACE events)
– Long-term safety (up to 52 weeks)
Novel Applications – Prevention of opioid-induced nausea and vomiting
– Treating postoperative gastrointestinal dysfunction
– Potential effects on recurrent acute pancreatitis
– Pediatric applications
Pharmacokinetic Measurements – Maximum plasma concentration (Cmax)
– Time to maximum concentration (Tmax)
– Area under the curve (AUC)
– Terminal elimination half-life
– Metabolite (nor-naldemedine) levels

FAQ

  • What is naldemedine and how does it work? Naldemedine is a peripherally acting μ-opioid receptor antagonist (PAMORA) that blocks opioid receptors in the gastrointestinal tract. Opioid medications can cause constipation by binding to these receptors and slowing down bowel function. Naldemedine specifically targets these receptors in the gut without crossing the blood-brain barrier, which means it can relieve constipation without interfering with the pain-relieving effects of opioids.
  • What conditions is naldemedine being studied for? Naldemedine is primarily being studied for opioid-induced constipation (OIC) in patients with chronic non-cancer pain who are receiving opioid therapy. Some trials are also investigating its use in pediatric patients receiving opioids, patients with postoperative gastrointestinal dysfunction following bowel surgery, and for potentially preventing opioid-induced nausea and vomiting in cancer patients. One study is even exploring its effects in patients with recurrent acute pancreatitis.
  • What dosages of naldemedine are being tested in clinical trials? Various dosages are being tested in different trials. For adults with opioid-induced constipation, most studies use 0.2 mg once daily, which appears to be the standard therapeutic dose. Some trials have tested lower doses (0.1 mg) and higher doses (0.4 mg) to determine the optimal balance of effectiveness and safety. For pediatric patients, doses are adjusted based on body weight, ranging from 0.05 mg to 0.2 mg. In studies for postoperative gastrointestinal dysfunction, higher doses of 1.25 mg, 2.5 mg, and 5 mg twice daily are being investigated.
  • What are the main outcomes being measured in naldemedine trials? The main outcomes vary by study but typically include changes in bowel movement frequency (particularly spontaneous bowel movements), time to first bowel movement after treatment, stool consistency, straining during bowel movements, and completeness of bowel movements. Researchers also measure adverse events, quality of life impacts, and patient-reported symptoms such as abdominal bloating and discomfort. In long-term studies, they evaluate the safety of naldemedine over extended periods, sometimes up to 52 weeks. Some studies also measure pharmacokinetic parameters to understand how the drug moves through the body.
  • Are there any safety concerns with naldemedine being studied? Safety is a major focus in the clinical trials. Researchers are particularly monitoring for adverse events related to gastrointestinal issues, as well as potential opioid withdrawal symptoms. Some studies use specific measurement tools like the Clinical Opiate Withdrawal Scale (COWS) and Webster Opiate Withdrawal Scale (WOWS) to monitor for withdrawal symptoms. Long-term studies are evaluating the safety profile over periods up to 52 weeks. One study is specifically investigating cardiovascular safety by examining major adverse cardiovascular events in patients using naldemedine compared to other OIC medications.

Ongoing Clinical Trials on NALDEMEDINE

  • Study on the Effects of Naldemedine and Tramadol on Opioid-Induced Bowel Dysfunction in Patients Using Opioids

    Recruiting

    2 1 1
    Investigated diseases:
    Investigated drugs:
    Denmark

Glossary

  • Opioid-Induced Constipation (OIC): A common side effect of opioid medications where the drugs bind to receptors in the gut, slowing down digestive processes and causing constipation. Unlike typical constipation, OIC often doesn't respond well to standard laxative treatments.
  • Peripherally Acting μ-Opioid Receptor Antagonist (PAMORA): A type of medication that blocks opioid receptors specifically in peripheral tissues like the digestive tract, without crossing the blood-brain barrier. This allows the medication to treat opioid side effects in the gut without interfering with pain relief.
  • Spontaneous Bowel Movement (SBM): A bowel movement that occurs naturally without the use of rescue laxatives or other medications within the previous 24 hours. This is a key measurement in OIC clinical trials.
  • Complete Spontaneous Bowel Movement (CSBM): A spontaneous bowel movement that gives the patient a feeling of complete evacuation or emptying of the bowels. This is considered a more meaningful outcome than just counting any bowel movement.
  • Bristol Stool Scale: A visual chart used to classify stool into seven categories based on appearance and consistency. Type 1 (separate hard lumps) and Type 2 (lumpy sausage-shaped) indicate constipation, Types 3-4 are considered normal, and Types 5-7 indicate increasingly loose stools or diarrhea.
  • Pharmacokinetics (PK): The study of how a drug moves through the body, including its absorption, distribution, metabolism, and excretion. PK parameters include measurements like maximum concentration (Cmax) and time to maximum concentration (Tmax).
  • Clinical Opiate Withdrawal Scale (COWS): A clinical tool used to assess and rate symptoms of opioid withdrawal. It includes 11 items measuring various symptoms, with scores ranging from 0 (no symptoms) to more than 36 (severe withdrawal).
  • Patient Assessment of Constipation Symptoms (PAC-SYM): A questionnaire that asks patients to rate the severity of 12 constipation symptoms on a scale from 0 (absent) to 4 (very severe). The results help measure the impact of constipation on a patient's quality of life.
  • Patient Assessment of Constipation Quality of Life (PAC-QOL): A 28-item questionnaire designed to measure how constipation affects a patient's daily life, including physical discomfort, psychosocial discomfort, worries and concerns, and satisfaction with bowel function.
  • Bowel Function Index (BFI): A clinical tool that measures constipation severity on a scale from 0 to 100, with higher scores indicating worse constipation. A score under 28.8 is generally considered normal bowel function.
  • Rescue Medication: Medications (typically laxatives) that patients are allowed to take during a clinical trial if their symptoms become too severe, despite the study treatment. The use of rescue medications is tracked as it can affect the interpretation of results.
  • Major Adverse Cardiovascular Event (MACE): A composite endpoint that typically includes cardiovascular death, non-fatal heart attack (myocardial infarction), and non-fatal stroke. This is being evaluated in a safety study of naldemedine.
  • Nor-naldemedine: A metabolite of naldemedine, which means it's a compound formed when the body breaks down naldemedine. Researchers measure levels of both naldemedine and nor-naldemedine to understand how the drug is processed in the body.
  • Straining Score: A measure of how much effort is required during a bowel movement, typically rated on a scale from 0 (no straining) to 4 (very severe straining). Reduced straining is a desired outcome in OIC treatment.
  • Terminal Elimination Half-life: The time it takes for the concentration of a drug in the body to reduce by half during the elimination phase. This helps determine how long a drug remains active in the body.

References

  1. https://clinicaltrials.gov/study/NCT01965652
  2. https://clinicaltrials.gov/study/NCT01993940
  3. https://clinicaltrials.gov/study/NCT03720613
  4. https://clinicaltrials.gov/study/NCT05588323
  5. https://clinicaltrials.gov/study/NCT01122030
  6. https://clinicaltrials.gov/study/NCT06334198
  7. https://clinicaltrials.gov/study/NCT01443403
  8. https://clinicaltrials.gov/study/NCT01965158
  9. https://clinicaltrials.gov/study/NCT04355169
  10. https://clinicaltrials.gov/study/NCT07038551
  11. https://clinicaltrials.gov/study/NCT04966559