The concept of dependence
When an individual consumes alcohol steadily over a long period, physiological processes gradually change so that the body can still function more or less normally despite the effects of alcohol. Subsequently, the body can only function properly when the alcohol is present. Alcohol effects the brain in a number of different ways and acamprosate and naltrexone act on different pathways in the brain.

When someone who is dependent on alcohol stops drinking, usually the symptoms of withdrawal become evident. These can be mild to severe and include the following: sweating, tremors, heart palpitations, increased body temperature, feelings of anxiety and agitation, and in severe cases hallucinations and loss of orientation. The symptoms of withdrawal can be present for up to months even when abstinent this whole period.



The effect of alcohol and acamprosate ("CampralĘ) on the brain

Short-term exposure to alcohol increases the actions of GABA on the GABA receptors and decreases those of excitatory amino acids such as glutamate on NMDA receptors. The result is that the electrical impulses triggered in the neurones are reduced, and activity in the brain and the nerves is depressed. With long term exposure, the body adapts by decreasing the activity of the GABA-ergic system and increasing the activity of the glutamate system.

When alcohol intake ceases, the depressant effect disappears, however, the neurones remain hyperexcitable. It takes many months for the brain to readapt and during this time alcohol withdrawal symptoms are experienced. Acamprosate acts to restore the GABA-ergic and glutamate neurone activity to 'normal' levels.

Acamprosate does not act like disulfram (antabuse), it does not block the rewarding effects of alcohol (like naltrexone), it is not a substitute for alcohol (like a tranquilliser or methadone in the case of heroin dependence), nor does it alter the effects of alcohol.

Physical symptoms: Acamprosate can protect against the CNS effects induced by alcohol withdrawal, such as shaking, cerebellar tremors, nervous twitches, and convulsions. Acamprosate has no effects on the cardiovascular, haemodynamic, respiratory, gastrointestinal or renal systems.

Absorption: After a single dose the maximum concentration is reached in 5 hours. At recommended dose (two 333mg tabs three times per day) steady state (or blood concentration levels) is reached at the end of 7 days. After this is achieved, the half life of Campral is 20.8 hours. Acamprosate is mainly eliminated unchanged in the urine, it is not metabolised.


When should I start taking Campral? It's recommended that patients should stop drinking for between 2-7 days before commencing treatment.

How long do the tablets take to work? Steady blood concentrations are reached after 7 days.

What are the side effects? Diarrhoea is the most common, followed by nausea, stomach pains, and an allergic skin reaction. Most side effects remit after a few weeks of treatment.

What will I feel taking these tablets? Unless you experience any of the side effects, you may not notice anything. Campral will not make you feel 'high' or sedated.

Will I have any cravings while taking Campral? Yes, Campral is not a magic tablet. It will help take the edge off the cravings and support your hard work in achieving abstinence.

What happens if I drink whilst taking Campral? Nothing. Campral does not alter the effects of alcohol. It is important to keep taking Campral even on days when you have had a drink. As Campral is quickly eliminated by the body, all doses (two tablets three times a day) need to be taken to maintain optimal blood concentration levels.

Is Campral addictive? You can stop taking Campral at any time without feeling symptoms of withdrawal from Campral. It is not habit forming.

What if I miss a dose? If you miss a dose, do not take extra tablets to make up for it. Take the next dose at the usual time.

Do I have to take Campral with food? It is best to take Campral with food, as this can help any stomach upset that you might experience.

Can I take other medications if needed? There are no known interactions with other medications. If necessary, Campral can be used with antidepressants, tranquillisers or disulfram. Taking Campral will not interfere with medication taken for long term illness such as diabetes, high blood pressure or peptic ulcers.

Do I have to take Campral for the rest of my life? No, the standard course of treatment is 6 months.

This information has been adapted from the Campral Product Monograph and the Campral Product Information forms, produced by Alphapharm, Pty Ltd.



The effect of alcohol and naltrexone on the brain

How does Naltrexone help me stop drinking? The naltrexone block the effects of drugs known as opioids. It competes with these drugs for opioid receptors in the brain. While the precise mechanism of action for the medications effect in alcohol treatment is unknown, there are 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 may interfere with the tendency to want to drink more if a recovering patient has a drink.

Does Naltrexone work? In research evaluating the effects of medication for alcohol dependence, people with alcohol dependence who received medication were twice as successful in remaining abstinent and in avoiding relapse as those who received placebo-an inactive pill.

If I drink, will naltrexone make me sober if I take it? No, naltrexone will not stop you being drunk if you drink. It does not reduce the effects of alcohol that impair coordination and judgement.

How long does naltrexone take to work take to work? Naltrexone effects on blocking opiate receptors will occur shortly after you have taken the first dose. The effects of naltrexone in helping patients remain abstinent and avoid relapse to alcohol use also occur early after first use.

Are there some people who should not take naltrexone? Naltrexone for alcohol dependence 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.

Is naltrexone addictive? No, naltrexone is not addictive.

Will naltrexone effect my ability to feel pleasure? While it does seem to reduce alcohol craving, it does not interfere with the experience of other types of pleasure such as sexual pleasure.

What does it feel like on naltrexone? Patients usually report that they are largely unaware of being on naltrexone. Naltrexone usually has no psychological effects and patients don't feel either "high" or "down"

What are the side effects of naltrexone? In the large studies of naltrexone side effects occurred in less than 1 in 10 people. The side effects that occurred were nausea, headache, dizziness, fatigue, insomnia, anxiety, and sleepiness. These side effects were usually mild and of short duration. In treating alcohol abuse nausea has been severe enough to discontinue naltrexone in less than 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.

Can I take other medications with naltrexone? 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. The major active effect of naltrexone for alcohol dependence is on opioid drugs. This class of drug is used to treat pain. The medication may therefore block the effect of any painkillers. Tell your physician if you are taking painkillers and they can prescribe non-narcotic pain reliever which can be used effectively while you are on the medication for alcohol dependence.

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.

Some answers adapted 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.