Carbamazepine

For an informed discussion with your doctor or pharmacist. This information collection is not a clinically validated interaction checker. Missing data do not establish safety. Do not change or stop prescribed medicines on the basis of this information. The findings apply to the specific conditions studied; laboratory and animal studies cannot be directly extrapolated to humans.

Active substance: Carbamazepine

Examples of brand names: Tegretal [DE]

ATC code: N03AF01

Main use (for orientation): Epilepsy; neuralgia

Documented research summary

A cannabis-smoking case involving cessation/resumption shows concentration changes, but changing carbamazepine doses and unknown cannabinoid composition limit causal interpretation. CL20 found no significant association between CBD dose and concentrations.

Uncertainties and limitations

A rat study shows different directions for acute/chronic exposure, not a quantitative human prediction. Do not categorise the case value of 9.1 µg/ml generally as supratherapeutic.

Separately recorded findings

1 separately recorded finding. Each statement applies to its documented study context.

CBD – clinical signals

Finding ID: B0057

Type of result: No / minor effect under the conditions studied

Observation: No concentration signal; p=0.6576.

Mechanism: PK observation

Study type: Observational study: no signal detected

Context studied: n=7.

Clinical interpretation: Not ruled out

Limitations and uncertainties: Context / limitations of CL20; a lack of statistical significance does not establish equivalence.

Original sources for this finding: Final analysis of potential drug-drug interactions between highly purified cannabidiol and anti-seizure medications in an open-label expanded access program [CL20]

References and access status

[CA_L_D0041] CARBATROL (CARBAMAZEPINE) CAPSULE, EXTENDED RELEASE [TAKEDA PHARMACEUTICALS AMERICA, INC.]

Original source / bibliographic reference

Authors: Takeda Pharmaceuticals America, Inc.

Year: 2026

Source type: Current published human-use SPL / product information

Source access – 23 October 2026: Source destination was accessible when checked.

Bibliographic attribution or source identity cross-checked.

[CL20] Final analysis of potential drug-drug interactions between highly purified cannabidiol and anti-seizure medications in an open-label expanded access program

Original source / bibliographic reference

Authors: Gaston TE; Bebin EM; Cutter GR; Grayson L; Szaflarski JP

Year: 2023

Source type: Open-label longitudinal observational study

DOI: 10.1002/epi4.12815

PMID: 37593907

Source access – 23 October 2026: Automated direct retrieval was restricted; this does not establish that the link is broken.

Bibliographic attribution or source identity cross-checked.

PubMed – bibliographic reference / abstract

DOI – publisher access (access restrictions may apply)

Europe PMC – full-text access according to the literature database – Listed as freely available HTML full text in the official Europe PMC metadata. Direct retrieval was not fully verified here.

[CA_P_34004090] A Change in Blood Carbamazepine Levels Associated With Cannabis Use: Implications for Clinical Practice.

Original source / bibliographic reference

Authors: Ridout KK, Young-Wolff KC, Ridout SJ.

Year: 2021

Source type: Research Support, Non-U.S. Gov't; Journal Article; Case Reports

DOI: 10.4088/jcp.20cr13777

PMID: 34004090

Source access – 23 October 2026: Direct retrieval could not be fully verified; availability remains unresolved.

Bibliographic attribution or source identity cross-checked.

DOI – publisher access (access restrictions may apply)

[CA_P_32424477] The effect of cannabidiol on the pharmacokinetics of carbamazepine in rats.

Original source / bibliographic reference

Authors: Darweesh RS, Khamis TN, El-Elimat T.

Year: 2020

Source type: Research Support, Non-U.S. Gov't; Journal Article

DOI: 10.1007/s00210-020-01878-2

PMID: 32424477

Source access – 23 October 2026: Source destination was accessible when checked.

Bibliographic attribution or source identity cross-checked.

DOI – publisher access (access restrictions may apply)

Research as of 23 October 2026. Not all original full texts could be reviewed in full. Source accessibility and the strength of scientific evidence must be assessed separately. An accessible link does not establish medical approval; a bibliographic record with an abstract does not replace the original full text.

Drug search and explanation of the evidence · Guide: cannabinoids and medicines · Author and responsibility