BLOCKING CANNABINOID CB1 RECEPTORS FOR THE TREATMENT OF NICOTINE DEPENDENCE: INSIGHTS FROM PRECLINICAL AND CLINICAL STUDIES

Abstract

“Tobacco use is one of the leading preventable causes of death in developed countries. Since existing medications are only partially effective in treating tobacco smokers, there is a great need for improved medications for smoking cessation. It has been recently proposed that cannabinoid CB(1) receptor antagonists represent a new class of therapeutic agents for drug dependence, and notably, nicotine dependence. Here, we will review current evidence supporting the use of this class of drugs for smoking cessation treatment. Pre-clinical studies indicate that nicotine exposure produces changes in endocannabinoid content in the brain. In experimental animals, N-piperidinyl-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methylpyrazole-3-carboxamide (rimonabant, SR141716) and N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide (AM251), two cannabinoid CB(1) receptor antagonists, block nicotine self-administration behavior, an effect that may be related to the blockade of the dopamine-releasing effects of nicotine in the brain. Rimonabant also seems efficacious in decreasing the influence of nicotine-associated stimuli over behavior, suggesting that it may act on two distinct neuronal pathways, those implicated in drug-taking behavior and those involved in relapse phenomena. The utility of rimonabant has been evaluated in several clinical trials. It seems that rimonabant is an efficacious treatment for smoking cessation, although its efficacy does not exceed that of nicotine-replacement therapy and its use may be limited by emotional side effects (nausea, anxiety and depression, mostly). Rimonabant also appears to decrease relapse rates in smokers. These findings indicate significant, but limited, utility of rimonabant for smoking cessation.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2752688/

Cannabinoid type 1 receptor antagonists (rimonabant) for smoking cessation.

“BACKGROUND:

Rimonabant is a selective type 1 cannabinoid (CB1) receptor antagonist. It may assist with smoking cessation by restoring the balance of the endocannabinoid system, which can be disrupted by prolonged use of nicotine. Rimonabant also seeks to address many smokers’ reluctance to persist with a quit attempt because of concerns about weight gain.”

“OBJECTIVES:

To determine whether selective CB1 receptor antagonists increase the numbers of people stopping smoking. To assess their effects on weight change in successful quitters and in those who try to quit but fail.”

“AUTHORS’ CONCLUSIONS:

From the preliminary trial reports available, rimonabant 20 mg may increase the odds of quitting approximately 1(1/2)-fold. Adverse events include nausea and upper respiratory tract infections; the risk of serious adverse events is reported to be low. However, there is current concern (August 2007) over rates of depression and suicidal thoughts in people taking rimonabant for weight control. The evidence for rimonabant in maintaining abstinence is inconclusive. Rimonabant 20 mg may moderate weight gain in the long term.”

http://www.ncbi.nlm.nih.gov/pubmed/17943852

Cannabinoid type 1 receptor antagonists for smoking cessation.

Abstract

“BACKGROUND:

Selective type 1 cannabinoid (CB1) receptor antagonists may assist with smoking cessation by restoring the balance of the endocannabinoid system, which can be disrupted by prolonged use of nicotine. They also seeks to address many smokers’ reluctance to persist with a quit attempt because of concerns about weight gain.”

“OBJECTIVES:

To determine whether selective CB1 receptor antagonists (currently rimonabant and taranabant) increase the numbers of people stopping smoking To assess their effects on weight change in successful quitters and in those who try to quit but fail.”

“AUTHORS’ CONCLUSIONS:

From the trial reports available, rimonabant 20 mg may increase the chances of quitting approximately 1½-fold. The evidence for rimonabant in maintaining abstinence is inconclusive. Rimonabant 20 mg may moderate weight gain in the long term. Taranabant 2-8 mg may moderate weight gain, at least in the short term. In 2008, development of both rimonabant and taranabant was discontinued by the manufacturers.”

http://www.ncbi.nlm.nih.gov/pubmed/21412887