Re: some interaction stuff

[Guest guest]

This is the offical list of interactions for the normal dose of naltrexone. One probably will not encounter any interactions at low dose, except fot the opioid thing. If you need any more info, please put something like attention Dr. Skip in the subject line. I had to read over 300 emails last week, most of them didn't concern me. tanks skip

Interactions

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Patients receiving phenothiazines, specifically thioridazine, and naltrexone concomitantly have had symptoms of somnolence and lethargy.[5887]

The safety and efficacy of concomitant use of naltrexone and disulfiram is unknown. Possible additive hepatotoxicity may occur. Concurrent use of these agents is not recommended unless the probable benefits outweigh the known risks. Naltrexone is contraindicated for use in patients who have acute hepatitis or liver failure. Before naltrexone is initiated, no active liver disease or severe liver problems should be present. Typical guidelines suggest liver function tests no greater than 3 times the upper limit of normal and normal bilirubin serum concentrations.[6993]

Naltrexone is contraindicated for use in patients who are in acute opioid withdrawal or who are dependent on opioids. If naltrexone is accidentally administered to a patient who takes methadone 50 mg/day or less on a daily basis, clonidine may attenuate withdrawal symptoms and lessen the time required for opiate withdrawal.[7033]

Naltrexone is contraindicated for use in patients currently receiving opiate agonists or mixed opiate agonists/antagonists (e.g., buprenorphine, butorphanol, nalbuphine, and pentazocine) including analgesics, antidiarrheal, or cough preparations or maintenance medications (e.g., methadone or levomethadyl).[6993] Naltrexone will antagonize the therapeutic benefits of opiate agonists or mixed opiate agonists/antagonists and will induce a withdrawal reaction in patients with physical dependence to opioids. Also, patients should be opiate-free for at least 7-10 days prior to initiating naltrexone therapy. If there is any question of opioid use in the past 7-10 days and the patient is not experiencing opioid withdrawal symptoms and/or the urine is negative for opioids, a naloxone challenge test needs to be performed. A negative test is defined as no evidence of withdrawal for 20 minutes after 0.8 mg naloxone SC or 0.2 mg naloxone IV followed 30 seconds later (if no symptoms) by 0.6 mg IV. If a patient receives naltrexone and an opiate agonist is needed for an emergency situation, large doses of opiate agonists may ultimately overwhelm naltrexone antagonism of opiate receptors. Immediately following administration of exogenous opiate agonists, the opiate plasma concentration may be sufficient to overcome naltrexone competitive blockade, but the patient may experience deeper and more prolonged respiratory depression and thus, may be in danger of respiratory arrest and circulatory collapse. Non-receptor mediated actions like facial swelling, itching, generalized erythema, or bronchoconstriction may occur presumably due to histamine release. A rapidly acting opiate agonist is preferred as the duration of respiratory depression will be shorter. Patients receiving naltrexone may also experience opiate side effects (respiratory insufficiency or arrest or circulatory collapse) with low doses of opiate agonists. If the opiate agonist is taken in such a way that high concentrations remain in the body beyond the time naltrexone exerts its therapeutic effects, serious side effects may occur.