Use of Guanfacine for Cannabis Use Disorder and Related Symptomology.

BACKGROUND AND OBJECTIVES: No medication has Food and Drug Administration approval for cannabis use disorder (CUD), and most medication development focuses on the withdrawal syndrome. We evaluated the effects of short-term treatment using the α-2A-adrenergic receptor agonist, guanfacine, on withdrawal symptoms in volunteers with CUD and a history of early onset of cannabis use. METHODS: Non-treatment-seeking healthy volunteers (n = 7) who met the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition criteria for CUD participated in a two-phase, within-subjects study. Volunteers received placebo or guanfacine (3 mg/day) for the first 8-day inpatient study and the alternative medication for the second 8-day inpatient study. On day 1 of both treatment periods, participants received 30 mg of synthetic Δ9 -tetrahydrocannabinol for standardization of abstinence onset. On days 2 to 7, participants received study medication. Cannabis withdrawal symptoms, sleep, craving, and physiology were assessed on all inpatient days. RESULTS: Compared with placebo, guanfacine did not show significant effects on withdrawal, craving, or sleep, although there were trends for guanfacine to increase positive mood symptoms and decrease craving-associated compulsivity. DISCUSSION AND CONCLUSIONS: Compared with former studies, we could not prove significant improvement in sleep or decrease of negative symptoms, but we found trends for increased positive mood symptoms. Our data did not show significant effects of guanfacine on withdrawal symptoms or craving. Due to early and longer cannabis use, our subjects indicate a great severity of illness increasing the likelihood of treatment resistance. SCIENTIFIC SIGNIFICANCE: On the basis of trends demonstrated here and other lines of evidence, further investigation is warranted regarding the utility of guanfacine as a potential treatment for CUD. (Am J Addict 2019;00:1-10).

Guanfacine Attenuates Adverse Effects of Dronabinol (THC) on Working Memory in Adolescent-Onset Heavy Cannabis Users: A Pilot Study.

The cannabinoid-1 receptor (CB1R) agonist Δ9-tetrahydrocannabinol (THC), the main psychoactive constituent of cannabis, adversely effects working memory performance in humans. The α2A-adrenoceptor (AR) agonist guanfacine improves working memory performance in humans. The authors aimed to determine the effects of short-term (6 days) treatment with guanfacine on adverse cognitive effects produced by THC. Employing a double-blind, placebo-controlled crossover design, the cognitive, subjective, and cardiovascular effects produced by oral THC (20 mg) administration were determined twice in the same cannabis users: once after treatment with placebo and once after treatment with guanfacine (3 mg/day). Compared with performance at baseline, THC negatively affected accuracy on spatial working memory trials while participants were maintained on placebo (p=0.012) but not guanfacine (p=0.497); compared with placebo, accuracy was significantly (p=0.003, Cohen's d=-0.640) improved while individuals were treated with guanfacine. Similarly, compared with baseline, THC increased omission errors on an attentional task while participants were maintained on placebo (p=0.017) but not on guanfacine (p=0.709); compared with placebo, there were significantly (p=0.034, Cohen's d=0.838) fewer omissions while individuals were maintained on guanfacine. Although THC increased visual analog scores of subjective effects and heart rate, these increases were similar during treatment with placebo and guanfacine. THC did not significantly affect performance of a recognition memory task or blood pressure while individuals were maintained on either treatment. Although preliminary, these results suggest that guanfacine warrants further testing as a potential treatment for cannabis-induced cognitive deficits.