Evidence-based treatment options: Pharmacology

Opioid addiction


Methadone is a medication used to treat Opioid Use Disorder (OUD). Methadone is a long-acting full opioid agonist, and a schedule 7 medication. (South Africa)

Methadone is dispensed as a medication-assisted-treatment (MAT) for the addiction of heroin. Methadone reduces opioid cravings and withdrawal symptoms and blocks the effects of opioids if used. The medication has an extended history in treating opioid dependence in adults. Methadone maintenance treatment is not a substitution for heroin / opioid use but rather helps people to sustain long-term recovery and regain productive and meaningful lives.

Comprehensive combined treatment: Methadone is prescribed as part of a comprehensive treatment plan that includes counselling and participation in support programs. Research indicates that methadone maintenance has even better outcomes when all medical, psychological, Psychiatric and /or social needs are assessed and referred for treatment.


Buprenorphine is a synthetic opioid medication that acts as a partial agonist at mu opioid receptors. The medication does not produce euphoria or sedation as caused by heroin or other opioids. Buprenorphine reduces withdrawal symptoms and carries a low risk of overdose.

Buprenorphine is available in its pure form or more commonly prescribed as Suboxone which combines buprenorphine with naloxone (an antagonist or opioid blocker) Naloxone has no effect unless the suboxone is injected in which case the naloxone will cause severe withdrawal symptoms. This formulation lessens the likelihood of abuse.

Medically- assisted- treatment NOT substitution

Methadone and buprenorphine are synthetic opioids and for this reason a view exists that in using these treatments the individual essentially replaces one drug for another. In reality, the use of these medications as prescribed and as part of treatment maintenance allows the person to live a normal life free of the behavioral and medical problems caused by the abuse of illicit drugs.


Naltrexone is a synthetic opioid antagonist that blocks opioids from binding to their receptors and prevents euphoria and sedative effects associated with the use of heroin, morphine and, codeine. Naltrexone works differently to Methadone and Buprenorphine in that instead of activating opioid receptors in order to suppress cravings its binds and blocks and through this mechanism reduces cravings. There is no deviation or abuse potential with naltrexone.

Naltrexone is usually prescribed as part of an outpatient treatment plan although this should begin after medical detox in an inpatient setting in order to prevent rapid withdrawal.

If the person relapses and uses heroin or other opioids, the mechanism of naltrexone prevents the euphoric feeling and this can be problematic if a person attempts to use more of the drug in an attempt to get high as this may end in overdose. People using naltrexone should not use any other opioids or illicit drugs; drink alcohol; or take sedatives, tranquilizers, or other drugs.

If patients on naltrexone discontinue use, they may have reduced tolerance to opioids and may be unaware of their potential sensitivity to the same, or lower, doses of opioids than they were used to. If patients who are treated with naltrexone relapse after a period of abstinence, it is possible that the dosage of opioid that was previously used may have life-threatening consequences, including respiratory arrest and circulatory collapse.

Clinicians with vast experience with this form of treatment find that naltrexone is better suited to highly motivated, recently detoxified patients who desire total abstinence due to external circumstances.

Alcohol addiction


Disulfiram (Antabuse®) causes unpleasant effects when even the smallest amount of alcohol is consumed. The effects begin approximately 10 minutes after alcohol enters the body and lasts for an hour or more. Disulfiram is not a cure for alcoholism, but discourages drinking.  The utility and effectiveness of disulfiram are considered limited because of poor adherence. However, it can be beneficial to strongly motivated individuals. Some people use it in high-risk situations, such as social occasions where alcohol is present. It can also be administered in a monitored fashion, such as in a clinic or by a spouse, improving its efficacy.


Acamprosate (Campral®) acts on the gamma-aminobutyric acid (GABA) and glutamate neurotransmitter systems and is thought to reduce symptoms of protracted withdrawal, such as insomnia, anxiety, restlessness, and dysphoria. Acamprosate has been shown to help dependent drinkers maintain abstinence for several weeks to months, and it may be more effective in patients with severe dependence.


Naltrexone blocks opioid receptors that are involved in the rewarding effects of drinking and the craving for alcohol. It has been shown to reduce relapse to problem drinking in some patients. An extended release version, Vivitrol—administered once a month by injection—is also FDA-approved for treating alcoholism, and may offer benefits regarding compliance.