Comparing biomarkers in regular cannabis users and non-users to find signs of recent inhalation

CANBiome: Pilot-Study for the Comparison of Biomarkers Between Regular Cannabis Users and Non-Users

We will test whether specific blood or other biological markers can indicate how recently regular cannabis smokers last inhaled by comparing them with non-users.

Quick facts

• Phase: NA
• Study type: Interventional
• Enrollment: 120 (estimated)
• Ages: 18 Years to 65 Years
• Sex: All
• Sponsor: University of Basel (other)
• Locations: 1 site (Basel)
• Trial ID: NCT06975020 on ClinicalTrials.gov

What this trial studies

This pilot interventional study recruits regular cannabis smokers and a comparison group of non-users to search for markers that approximate the timing of the last inhalation. Participants will prepare and inhale their usual cannabis product (up to 15 minutes) and provide blood and possibly other biological samples for measurement of THC, metabolites, and candidate biomarkers. The study focuses on factors that might explain individual differences in THC pharmacokinetics and pharmacodynamics. Results will guide future research to better distinguish impaired from unimpaired cannabis users in road-traffic settings.

Who should consider this trial

Good fit: Ideal candidates are adults aged 18–65 who smoke cannabis about once a week (may mix with tobacco), hold a driving license, speak German, and can avoid cannabis, nicotine, and alcohol before the visit.

Not a fit: People with current or past major psychiatric disorders, pregnant or breastfeeding individuals, those taking strong CYP2C9/2C19/3A4 inducers or inhibitors, or people who do not match the regular-use or non-use groups are unlikely to gain direct benefit from participation.

Why it matters

Potential benefit: If successful, the study could identify objective markers that help determine how recently someone inhaled cannabis, improving road-safety decisions and legal guidance.

How similar studies have performed: Previous research has shown that THC blood levels poorly predict impairment and studies of alternative markers are limited and have not yet produced a reliable, widely accepted test.

Eligibility criteria

Inclusion Criteria:

* Experience of smoking cannabis products, on average once a week. This may be in combination with tobacco.
* Age 18-65 years Possession of driving license in at least one of the categories A, B, A1; B1, F, G or M
* Sufficient knowledge of German
* No cannabis inhalation or nicotine consumption on study day
* No alcohol consumption within the last 24 h

Exclusion Criteria:

* Participation in a trial with investigational drugs within 30 days
* Current or previous major psychiatric disorder (e.g., major depression, schizophrenia spectrum disorder)
* Pregnancy or breastfeeding
* Intake of CYP2C9, CYP2C19, and CYP3A4-inducers in the last 4 weeks before the study visit, e.g. rifampicin (antibiotic), carbamazepine (anticonvulsant), phenobarbital (anticonvulsant), phenytoin (anticonvulsant) or inhibitors, such as amiodarone (class III antiarrhythmic medication), antifungal drugs such as fluconazole, miconazole, voriconazole and itraconazole, antibiotics such as clarithromycin and sulfamethoxazole, ritonavir (protease inhibitor) and grapefruit juice.
* The following conditions: vasopressin deficiency, pituitary tumor, active malignancy, severe hyponatremia requiring treatment, congestive heart failure, liver cirrhosis.

Where this trial is running

Basel

• Insitute of forensic medicine — Basel, Switzerland (RECRUITING)

Study contacts

• Study coordinator: Urs Duthaler, PhD

Conditions: Driving Under the Influence of Cannabis, Cannabis, Driving, Biomarker