Naloxone is a drug used to counter the effects of overdosing on opiates such as heroin or morphine. It is being offered under the trade names Narcan, Nalone, and Narcanti.
The drug is derived from thebaine and has an extremely high affinity for the opiate receptors on nerve cells in the brain, and blocks those receptors quickly, often throwing addicts into immediate withdrawal symptoms. It acts as a competitive antagonist, being structurally similar to morphine while lacking morphine-like effects.
Naloxone is injected, usually initially intravenously for fastest action. The drug acts after about two minutes, and its effects may last about 45 minutes.
Naloxone has been distributed as part of emergency kits to heroin addicts, which has been shown to reduce death rates.
The drug also blocks the action of pain-lowering endorphins which the body produces naturally. The likely reason for this is that these endorphins operate on the same opiate receptors. In one experiment, women treated with naloxone reported higher pain levels during childbirth than women not so treated; in another experiment, the pain lowering effect of placebos was blocked if the placebos were administered along with naloxone.
While naloxone is still often used in emergency treatments for opiate overdose, its clinical use in ongoing treatment of users with opiate addiction is being increasingly superseded by naltrexone. Naltrexone blocks a wider range of opiate receptors and blocks the receptors for a significantly longer time.
Frequently Asked Questions About Naltrexone
- What is naltrexone? -- Naltrexone is a medication that blocks the effects of drugs known as opioids (a class that includes morphine, heroin or codeine). It competes with these drugs for opioid receptors in the brain. It was originally used to treat dependence on opioid drugs but has recently been approved by the FDA as treatment for alcoholism. In clinical trials evaluating the effectiveness of naltrexone, patients who received naltrexone were twice as successful in remaining abstinent and in avoiding relapse as patients who received placebo-an inactive pill.
- Why does naltrexone help for alcoholism? -- While the precise mechanism of action for naltrexone's effect is unknown, reports from successfully treated patients suggest three kinds of effects. First, naltrexone can reduce craving, which is the urge or desire to drink. Second, naltrexone helps patients remain abstinent. Third, naltrexone can interfere with the tendency to want to drink more if a recovering patient slips and has a drink.
- Does this mean that naltrexone will "sober me up" if I drink? -- No, naltrexone does not reduce the effects of alcohol that impair coordination and judgement.
- If I take naltrexone, does it mean that I don't need other treatment for alcoholism? -- No, naltrexone is only one component of a program of treatment for alcoholism including counseling, help with associated psychological and social problems and participation in self-help groups. In both studies where naltrexone \was shown to be effective, it was combined with treatment from professional psychotherapists.
- How long does naltrexone take to work? -- Naltrexone's effects on blocking opioids occurs shortly after taking the first dose. Findings to date suggest that the effects of naltrexone in helping patients remain abstinent and avoid relapse to alcohol use also occur early.
- Are there some people who should not take naltrexone? -- Naltrexone should not be used with pregnant women, individuals with severe liver or kidney damage or with patients who cannot achieve abstinence for at least 5 days prior to initiating medications. Also, people who are dependent on opioid drugs, like heroin or morphine must stop their drug use at least 7 days prior to starting naltrexone.
- What does it feel like to be on naltrexone? -- Aside from side effects, which are usually short-lived and mild, patients usually report that they are largely unaware of being on medications. Naltrexone usually has no psychological effects and patients don't feel either "high" or "down" while they are on naltrexone. It is not addicting. While it does seem to reduce alcohol craving, it does not interfere with the experience of other types of pleasure.
- What are the side effects of naltrexone? -- In the largest study, the most common side effect of naltrexone affected only a small minority of people and included the following: nausea (10%), headache (7%), dizziness (4%), fatigue (4%), insomnia (3%), anxiety (2%), and sleepiness (2%). These side effects were usually mild and of short duration. As treatment for alcoholism, naltrexone side effects, predominantly nausea, have been se vere enough to discontinue the medication in 5-10% of the patients starting it. For most other patients side effects are mild or of brief duration. One serious possibility is that naltrexone can have toxic effects on the liver. Blood tests of liver function are performed prior to the onset of treatment and periodically during treatment to determine whether naltrexone should be started and whether it should be discontinued if the relatively rare side effect of liver toxicity is taking place.
- Do I need to get blood tests while I'm on naltrexone? How often? -- To ensure that naltrexone treatment is safe, blood tests should be obtained prior to initial treatment. Following that, retesting generally occurs at monthly intervals for the first three months, with less frequent testing after that point. More frequent testing may be requested depending on the health of your liver prior to beginning treatment. Blood tests are needed to make sure that liver function is adequate prior to taking naltrexone and to evaluate whether naltrexone is having adverse effects on the liver.
- Can I take other medications with naltrexone? -- The major active effect of naltrexone is on opioid drugs, which is one class of drugs used primarily to treat pain but is also found in some prescription cough preparations. Naltrexone will block the effect of normal doses of this type of drug. There are many non-narcotic pain relievers that can be used effectively while you are on naltrexone. Otherwise, naltrexone is likely to have little impact on other medications patients commonly use such as antibiotics, non-opioid analgesics (e.g., aspirin, acetaminophen, ibuprofen), and allergy medications. You should inform your physician of whatever medication you are currently taking so that possible interactions can be evaluated. Because naltrexone is broken down by the liver, other medications that can affect liver function may affect the dose of naltrexone.
- Will I get sick If I drink while on naltrexone? -- No. Naltrexone may reduce the feeling of intoxication and the desire to drink more, but it will not cause a severe physical response to drinking.
- Will I get sick If I stop naltrexone suddenly? -- Naltrexone does not cause physical dependence and it can be stopped at any time without withdrawal symptoms. In addition, available findings regarding cessation do not show a "rebound" effect to resume alcohol use when naltrexone is discontinued.
- What should I do If I need an operation or pain medication? -- You should carry a card explaining that you are on naltrexone and that also instructs physicians on pain management. Many pain medications that are not opioids are available for use. If you are going to have elective surgery, naltrexone should be discontinued at least 72 hours beforehand.
- What Is the relationship of naltrexone to AA? -- There is no contradiction between participation in AA and taking naltrexone. Naltrexone is not addictive and does not produce any "high" or pleasant effects. It can contribute to achievement of an abstinence goal by reducing the craving or compulsion to drink, particularly during early phases of recovery. It is most likely to be effective when the patient's goal is to stop drinking altogether.
- How long should I stay on naltrexone? -- If naltrexone is tolerated and the patient is successful in reducing or stopping drinking, the recommended initial course of treatment is 3 months. At that time the patient and clinical staff should evaluate the need for further treatment on the basis of degree of improvement, degree of continued concerns about relapse and level of improvement in areas of functioning other than alcohol use.
*From the Pamphlet "Guidelines for the Use of Naltrexone in the Treatment of Alcoholism" by Bruce J. Rounsaville, M.D., Stephanie O'Malley, Ph.D., and Patrick O'Connor, M.D. - The APT Foundation, 904 Howard Avenue, New Haven, CT 06519.