In treating addiction to alcohol, opioids, cannabis, and cocaine, doctors might prescribe a drug to the client to help with the detoxification process. These prescribed drugs might be given a short or long time depending on individual need. In some cases, these drugs block receptors so that if the client uses the drug, no feeling of "high" would occur (e.g. methadone blocks heroin). In other cases, the client takes the prescribed drug knowing that he/she will become ill if also taking the illicit drug or alcohol. Occasionally, the drugs used in pharmacotherapy can be addictive (e.g. methadone).

To respond to the discussion questions, please complete the assigned reading including Agonist Therapies: One Person's Cure Is Another's Addiction (below) of your text.

1. Do you think that agonist therapies should be continued despite the danger that some people become addicted to the agonist drug? Support your position using the text or other academic resource.
2. Choose one of the treatment drugs listed in the 18.2 Table (below) and research its use in treatment for alcohol, nicotine, opioid, cocaine, or cannabis treatment. Explain its action in the brain (e.g. does it block receptors).
3. Would you recommend the drug that you researched for use in pharmacotherapy? Support your opinion with information from your research.

 

Taking Sides Agonist Therapies: One Person's Cure Is Another's Addiction

In the mid-1960s, Drs. Vincent Dole and Marie Nyswander reported that methadone, a long-acting opioid agonist, was an effective treatment for reducing heroin dependence. Subsequently, a plethora of studies have shown that methadone treatment also reduces high-risk injecting and sexual behaviors, increases HIV treatment retention, and improves antiretroviral medication adherence. The idea is that maintaining patients on a medication pharmacologically similar to the abused drug (e.g., heroin) will, in turn, decrease the desire for the illicit substance. An added benefit is that methadone and most other maintenance medications are administered via the oral route, which is safer and produces diminished psychoactive effects. Thus, although methadone is not a cure and must be taken by patients indefinitely, arguably it is the most effective substance-abuse treatment medication. The rationale for nicotine replacement therapies in treating nicotine dependence is based in large part on the success of methadone maintenance treatment.

Given the fact that methadone maintenance has been largely successful in treating heroin dependence, it seems peculiar that a similar strategy has not been implemented to address cocaine dependence or methamphetamine dependence. In opioid and nicotine dependence, the neurobiological mechanisms mediating reinforcement are fairly well understood, making the development of treatment medications relatively straightforward. In contrast, the neuronal mechanisms of action for cocaine and amphetamines are more complicated, rendering the development of effective pharmacotherapies more difficult. As such, there is currently no "methadone for cocaine" per se. However, the knowledge that methamphetamine and other amphetamines produce considerable overlapping effects has led to investigations of oral d-amphetamine for treating methamphetamine dependence. Initial results have been encouraging, but the verdict is still out on this approach.

Despite the successes described above, agonist treatments have been contentious since their inception, and they remain a source of controversy today. Some argue, for example, that methadone entraps patients in lifelong drug dependence such that they are merely trading one "addiction" for another. Indeed, patients receiving methadone are required to take daily doses of the drug. Interestingly, this argument is rarely mentioned when discussing the use of insulin for diabetes or antihypertensive medications for high blood pressure. Patient afflicted with these conditions are required to take their medication on a daily basis but are not considered "addicted" to these medications. Similarly, many individuals currently take medications daily to treat psychiatric disorders, including depression and ADHD, but they are not viewed as disparagingly as methadone-maintained individuals.

Considering the potential benefits and concerns associated with agonist treatments, do you think greater emphasis should be placed on expanding this strategy for treating substance dependence? Or should agonist therapies be curtailed to prevent creating another type of drug dependence?

 

 

 

 

Table 18.2

Medications Used to Treat Substance Abuse and Dependence

Substance Treatment Medication Proposed Mechanism(s) of Action

Alcohol Benzodiazepines Increase the activity of GABA

Disulfiram Inhibits aldehyde dehydrogenase

Naltrexone Opioid receptor antagonist

Acamprosate Normalizes basal GABA concentrations; blocks alcohol-withdrawal-induced glutamate increases

Nicotine Nicotine replacements Full agonists at nicotine receptors

Bupropion Inhibits the reuptake of dopamine and norepinephrine; acetylcholine receptors antagonist

Varenicline Partial nicotine-receptor agonist

Opioids Methadone Full agonist at opioid receptors

Buprenorphine Partial agonist at opioid receptors

Naltrexone Opioid receptor antagonist

Cocaine Modafinil * Increases the activity of dopamine, norepinephrine, and glutamate; decreases the release of GABA Cannabis

Dronabinol * Full agonist at cannabinoid receptors

 

* Not FDA approved to treat substance abuse or dependence.