What topics does this cannabis study cover?

This study covers research on: Pain.

Where was this research published?

Published in Clinical pharmacology and therapeutics on February 1, 2026.

Pain

CBD's surprising effects on common medications revealed

Q: What did this research study find?

**CBD increased citalopram plasma concentration by 43%** through enzyme interaction mechanisms

Clinical Study to Evaluate Drug Interactions of Cannabidiol with Citalopram and Morphine in Healthy Adults.

Clinical pharmacology and therapeutics • February 1, 2026 • Highly Relevant

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AI Summary

This clinical study investigated potential drug interactions between cannabidiol (CBD) and two commonly prescribed medications: citalopram (an antidepressant) and morphine (a pain medication). Researchers examined how daily CBD consumption at typical unregulated product doses might affect the way these drugs are processed in the human body.

The study revealed significant interactions with citalopram, where CBD notably increased the drug's plasma concentration. Specifically, the area under the plasma concentration-time curve (AUC) for citalopram increased by 43% when taken alongside CBD. In contrast, the interactions with morphine were less pronounced, with only modest changes in drug metabolism observed.

These findings have important implications for patients using CBD alongside other medications. The research highlights the potential need for careful medication management when consuming CBD, particularly with drugs metabolized by specific liver enzymes. Cytochrome P450 enzyme interactions suggest that CBD could potentially alter the effectiveness or side effects of certain medications, emphasizing the importance of consulting healthcare providers before combining CBD with prescription drugs.

💡 Key Findings

CBD increased citalopram plasma concentration by 43% through enzyme interaction mechanisms

High

85%

Morphine interactions were minimal, with only slight changes in drug metabolism

Good

75%

Potential for significant pharmacokinetic interactions with cytochrome P450 enzymes

High

80%

📄 Original Abstract

Cannabidiol (CBD) is one of the most abundant bioactive cannabinoids. Research has demonstrated CBD's ability to inhibit metabolic enzymes like cytochrome P450 (CYP) and UDP-glucuronosyltransferase (UGT), potentially leading to drug interactions. However, clinical knowledge gaps remain, particularly with regard to drugs that are more commonly taken by consumers of unregulated CBD products. This study aimed to characterize the effects of daily CBD consumption, at doses typical of unregulated CBD products, on the pharmacokinetics of citalopram and morphine. These two commonly prescribed medications are metabolized by CYPs and UGTs, respectively. This open-label, sequential study involved two cohorts of 20 healthy participants. Cohort one received a single dose of citalopram (20 mg) on days 1 and 13, with CBD (2.5 mg/kg twice daily) administered for 12 days. Cohort two received a single dose of morphine (15 mg) on days 1, 4, and 11, with CBD (2.5 mg/kg twice daily) given for 9 days. The geometric mean ratio (GMR, [90% confidence interval]) for citalopram with and without CBD for 12 days was 1.43 (1.34-1.52) for the area under the plasma concentration-time curve (AUC0-inf) and 1.12 (1.06-1.17) for the maximum observed plasma concentration (Cmax). The GMR for AUC0-inf and Cmax for morphine coadministered with CBD compared to morphine alone was 1.06 (0.96-1.16) and 1.19 (1.05-1.35), respectively. For morphine with CBD for 9 days compared to morphine alone, the GMR for AUC0-inf and Cmax was 1.12 (1.00-1.26) and 1.11 (0.94-1.30), respectively. While a significant pharmacokinetic interaction between CBD and citalopram was observed, interactions between CBD and morphine, as well as its metabolites, were limited.

Paper Type

📄 Research

Publication

Journal: Clinical pharmacology and therapeutics
Published: February 1, 2026
PMID: 41622700
DOI: 10.1002/cpt.70219

Authors (12)

Pablo Salcedo Division of Applied Regulatory Science, Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA.
Donna A Volpe Division of Applied Regulatory Science, Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA.
Anik Chaturbedi Division of Applied Regulatory Science, Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA.
Aanchal Shah Division of Applied Regulatory Science, Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA.
Ashok Krishna Division of Applied Regulatory Science, Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA.
+7 more authors