Drug Interaction Report

CONTRAINDICATED: Naltrexone can antagonize the effects of opioids via competitive inhibition of opioid receptors. Patients receiving naltrexone may not benefit from opioid-containing medications such as cough and cold products, antidiarrheal preparations, and narcotic analgesics. Likewise, patients dependent on opioids may experience withdrawal symptoms when given naltrexone. Following use of naltrexone, patients may have increased sensitivity to opioids.

**Note: This warning does not apply to opioid products that are specifically formulated with naltrexone to deter abuse via snorting or intravenous injection when crushed.**

MANAGEMENT: The use of naltrexone is considered contraindicated in patients receiving opioids or dependent on opioids, including those maintained on opiate agonists (e.g., methadone) or partial agonists (e.g., buprenorphine). Naltrexone should also not be given to patients in acute opioid withdrawal. In an urgent situation when analgesia may be required in a patient who has received full blocking doses of naltrexone, consideration should be given to regional analgesia, conscious sedation with a benzodiazepine, use of non-opioid analgesics, or general anesthesia. If opioid analgesia is required, the amount of opioid needed may be greater than usual, and the resulting respiratory depression may be deeper and more prolonged. A rapidly-acting opioid analgesic that minimizes the duration of respiratory depression is preferred. Clinicians should be aware that reversal of full naltrexone blockade by administration of large doses of opiates can cause histamine release. Therefore, patients may experience non-opioid receptor-mediated effects such as facial swelling, itching, generalized erythema, and bronchoconstriction. Irrespective of the drug chosen to reverse naltrexone blockade, the patient should be monitored closely by appropriately trained personnel in a setting equipped and staffed for cardiopulmonary resuscitation.

MONITOR CLOSELY: Concomitant use of esketamine with central nervous system (CNS) depressants may increase sedation and impairment of attention, judgment, thinking, reaction speed, and psychomotor skills. In clinical trials, 49% to 61% of esketamine-treated patients developed sedation based on the Modified Observer's Alertness/Sedation scale (MOAA/s), and 0.3% of esketamine-treated patients experienced loss of consciousness (MOAA/s score of 0). In the MOAA/s scale, 5 means "responds readily to name spoken in normal tone" and 0 means "no response after painful trapezius squeeze," and any decrease in MOAA/s from pre-dosing of esketamine is considered to indicate presence of sedation. Dose-related increases in the incidence of sedation were also observed in a fixed-dose study. Additionally, cognitive performance decline was reported in a study in healthy volunteers who received a single intranasal dose of esketamine. Compared to placebo-treated subjects, esketamine-treated subjects required a greater effort to complete cognitive tests at 40 minutes post-dose, although results were comparable between the two groups at 2 hours post-dose. Drowsiness was comparable after 4 hours post-dose.

MANAGEMENT: Caution is advised and patients should be closely monitored during concomitant use of esketamine with CNS depressants or other drugs that can cause sedation or dizziness. Due to the risk of delayed or prolonged sedation and other adverse effects, patients should be monitored for at least 2 hours after esketamine administration, followed by an assessment to determine when the patient is considered clinically stable and ready to leave the healthcare setting. Patients should be instructed not to engage in potentially hazardous activities that require complete mental alertness and motor coordination, such as driving a motor vehicle or operating machinery, until the next day after a restful sleep.

GENERALLY AVOID: Alcohol may potentiate the central nervous system (CNS) depressant effects of opioid analgesics including morphine and diamorphine. Concomitant use may result in additive CNS depression and impairment of judgment, thinking, and psychomotor skills. In more severe cases, hypotension, respiratory depression, profound sedation, coma, or even death may occur.

GENERALLY AVOID: Consumption of alcohol while taking some sustained-release formulations of morphine may cause rapid release of the drug, resulting in high systemic levels of morphine that may be potentially lethal. Alcohol apparently can disrupt the release mechanism of some sustained-release formulations. The interaction was observed in in vitro studies using a 24-hour morphine formulation (Avinza 30 mg capsule, available in the U.S. from Ligand Pharmaceuticals). When the capsule was mixed with 900 mL of buffer solutions containing ethanol 20% and 40%, the dose of morphine that was released was alcohol concentration-dependent, leading to a more rapid release of morphine. Although the clinical relevance of this finding is unknown, 'dose-dumping' into the bloodstream is conceivable.

MANAGEMENT: Until more information is available, patients taking sustained-release formulations of morphine should not consume alcohol or use medications that contain alcohol. In general, potent narcotics such as morphine or diamorphine should not be combined with alcohol.

GENERALLY AVOID: Concomitant use of esketamine with central nervous system (CNS) depressants such as alcohol may increase sedation and impairment of attention, judgment, thinking, reaction speed, and psychomotor skills.

ADJUST DOSING INTERVAL: Nausea and vomiting may occur following intranasal administration of esketamine. In clinical studies, nausea and vomiting were reported in approximately 25% and 10% of esketamine-treated patients, respectively.

MANAGEMENT: Patients receiving esketamine should be advised to avoid or limit the consumption of alcohol. In addition, to help prevent nausea and vomiting, patients should be advised not to eat for at least 2 hours before intranasal administration of esketamine and not to drink liquids for at least 30 minutes prior to administration.

GENERALLY AVOID: Coadministration of naltrexone with other agents known to induce hepatotoxicity may potentiate the risk of liver injury. Naltrexone, especially in larger than recommended doses (more than 50 mg/day), has been associated with hepatocellular injury, hepatitis, and elevations in liver transaminases and bilirubin. Other potential causative or contributory etiologies identified include preexisting alcoholic liver disease, hepatitis B and/or C infection, and concomitant usage of other hepatotoxic drugs.

MANAGEMENT: The use of naltrexone with other potentially hepatotoxic agents should be avoided whenever possible (e.g., acetaminophen; alcohol; androgens and anabolic steroids; antituberculous agents; azole antifungal agents; ACE inhibitors; cyclosporine (high dosages); disulfiram; endothelin receptor antagonists; interferons; ketolide and macrolide antibiotics; kinase inhibitors; minocycline; nonsteroidal anti-inflammatory agents; nucleoside reverse transcriptase inhibitors; proteasome inhibitors; retinoids; sulfonamides; tamoxifen; thiazolidinediones; tolvaptan; vincristine; zileuton; anticonvulsants such as carbamazepine, hydantoins, felbamate, and valproic acid; lipid-lowering medications such as fenofibrate, lomitapide, mipomersen, niacin, and statins; herbals and nutritional supplements such as black cohosh, chaparral, comfrey, DHEA, kava, pennyroyal oil, and red yeast rice). Patients should be advised to seek medical attention if they experience potential signs and symptoms of hepatotoxicity such as fever, rash, itching, anorexia, nausea, vomiting, fatigue, malaise, right upper quadrant pain, dark urine, pale stools, and jaundice. Periodic monitoring of hepatic function is advisable.