Pilot trial finds guanfacine feasible for cannabis use disorder with significant use reductions | Research

The takeaway

In a small open-label pilot trial, guanfacine extended-release was feasible and well-tolerated for cannabis use disorder, with significant reductions in daily cannabis amount, spending, and use days over 8 weeks.

Addiction medicine clinicians, researchers studying cannabis use disorder treatments

Significant reductions in cannabis use (grams, dollars, days); 41% retention at 8 weeks

What the researchers found

Among 22 cannabis-dependent individuals, daily cannabis use in grams (p = .004), dollars spent (p < .001), and days of use (p = .007) significantly decreased over the 8-week study. Retention at week 8 was 41%. Three participants achieved 3+ weeks of total abstinence. No significant differences between two titration schedules.

Why it matters

No approved pharmacotherapy exists for cannabis use disorder. This pilot suggests guanfacine, an alpha-2 adrenergic agonist already approved for ADHD, warrants further study as a potential treatment.

The numbers in context

22 participants; 41% retention at 8 weeks; significant reductions in grams (p = .004), dollars (p < .001), and days of use (p = .007); 3 participants achieved 3+ weeks abstinence.

How the study worked

Eight-week open-label outpatient pilot trial of guanfacine extended-release (G-XR) in 22 cannabis-dependent adults. Two titration schedules tested (gradual to 4 mg or highest tolerated dose). Standard medication management provided.

What this study cannot tell us

Open-label without placebo control; very small sample; 41% retention suggests tolerability challenges; natural reduction over time cannot be excluded.

How to read the evidence

Small open-label pilot without placebo control; designed as a feasibility study.

When this study was published

Published in 2020.

The bigger picture

With cannabis use disorder increasing alongside legalization, the absence of effective medications is a major treatment gap. Repurposing existing medications like guanfacine offers a faster path to potential treatments.

Questions still open

Would a placebo-controlled trial confirm these reductions? Could guanfacine be combined with behavioral interventions for better outcomes?

Common questions

What is guanfacine and why might it help cannabis addiction?

Guanfacine is an alpha-2 adrenergic agonist approved for ADHD and hypertension. It may help cannabis use disorder by reducing withdrawal symptoms and improving behavioral control, which are key challenges in cannabis cessation.

Is this now a treatment for cannabis addiction?

Not yet. This was a small pilot study to test feasibility. The results are promising enough to warrant a larger, placebo-controlled trial to determine if guanfacine truly reduces cannabis use beyond what would happen naturally.

Read the original research

Guanfacine extended-release for cannabis use disorder: a pilot feasibility trial.

The American journal of drug and alcohol abuse, 46(1), 44-48

View on PubMed ↗Publisher’s paper ↗

Citation

Dakwar, Elias; Mahony, Amy; Choi, C Jean; Pavlicova, Martina; Brooks, Daniel; Mariani, John P; Levin, Frances R. (2020). Guanfacine extended-release for cannabis use disorder: a pilot feasibility trial.. The American journal of drug and alcohol abuse, 46(1), 44-48. https://doi.org/10.1080/00952990.2019.1620259