Information about Naloxegol
Liver safety of Naloxegol
Naloxegol has not been linked to serum enzyme elevations during therapy or to clinically apparent liver injury.
Mechanism of action of Naloxegol
Naloxegol (nal ox' ee gol) is a pegylated, semisynthetic opiate receptor antagonist which is similar structurally to naltrexone, but is peripherally restricted and thus has few if any effects on the central nervous system. Naloxegol is a polyethylene glycol (PEG) derivative of alpha-naloxol, an opiate antagonist. The addition of the large PEG molecule to naloxol does not block its engagement with opioid receptors, but does prevent the drug from crossing the blood brain barrier. As a consequence, the opioid antagonist reverses the peripheral but not the central nervous system effects of opiates, such as pain relief and euphoria. In large, preregistration trials, naloxegol was found to increase spontaneous bowel movement frequency and reduce constipation related side effects of opiates used for analgesia in patients with chronic pain.
FDA approval information for Naloxegol
Naloxegol was approved for use in the United States in 2014 and is available as tablets of 12.5 and 25 mg under the brand name Movantik. The recommended dosage is 25 mg once daily, reducing the dose to 12.5 mg daily for intolerance.
Side effects of Naloxegol
Side effects include abdominal pain, diarrhea, nausea, flatulence, anxiety, restlessness and sweating. Withdrawal symptoms can occur, but are rare. In persons not taking opioids, naloxegol has minimal effects on constipation.