Naloxegol is a peripherally acting μ-opioid receptor antagonist developed by AstraZeneca, licensed from Nektar Therapeutics, for the treatment of opioid-induced constipation. It was approved in 2014 in adult patients with chronic, non-cancer pain. Mechanistically, naloxegol is a polyethylene glycol conjugate of a naloxone derivative that reduces central nervous system penetration and selectively blocks peripheral μ-opioid receptors in the gastrointestinal tract to restore intestinal motility without reversing central analgesia. Typical clinical dosing is 25 mg orally once daily; patients who do not tolerate 25 mg may be reduced to 12.5 mg once daily. Pharmacokinetic characteristics include oral absorption with median Tmax around 2 hours, elimination half-life in the range of approximately 6 to 11 hours, clearance influenced by P-glycoprotein transport and CYP3A4-mediated metabolism, and primary excretion in feces with limited renal elimination. Concomitant use with strong CYP3A4 inhibitors is contraindicated because of marked exposure increases, and dose adjustment or caution is required with moderate CYP3A4 inhibitors.
Technical specifications for naloxegol active substance (commonly supplied as the oxalate salt) include an assay for potency and limits for related substances and degradation products; typical impurity control criteria used by manufacturers and quality control laboratories set individual unspecified impurities at or below 0.1 to 0.2% by area and total impurities not to exceed approximately 1.0% by area, with tighter limits applied to specified known impurities. Relevant related compounds and potential degradants consist of PEG chain-length homologues (shorter or longer PEG adducts), N-dealkylated and demethylated analogues, N-oxide species, des-PEG or partially cleaved PEG impurities, ring-opened or hydrolytic products, residual solvents within ICH Q3C limits, and trace metal and water content controlled per pharmacopeial limits. Analytical methods typically include HPLC with validated impurity profiling, mass spectrometric confirmation for specified degradants, and stability-indicating assays to monitor formation of related substances during storage and manufacturing.
Naloxegol is used to treat opioid-induced constipation in adult patients receiving opioids for chronic, non-cancer pain who have had inadequate response to laxative therapy. It targets peripheral μ-opioid receptors in the gut to increase bowel motility without reversing central opioid analgesia.
Naloxegol is not a traditional laxative class such as osmotic or stimulant agents. It is a peripherally acting μ-opioid receptor antagonist, often described as a PAMORA, that alleviates opioid-induced constipation by blocking peripheral opioid receptors in the gastrointestinal tract.
Yes. MOVANTIK is the brand name under which naloxegol oxalate is marketed by AstraZeneca. Naloxegol is the active ingredient in MOVANTIK.
Onset of effect is commonly reported within 24 hours after the first dose; many patients experience a bowel movement within about 6 to 12 hours. Individual response times vary based on factors such as opioid use, concomitant medications, and gastrointestinal status.
