Topiramate

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: Topiramate

Examples of brand names: Topamax [DE]

ATC code: N03AX11

Main use (for orientation): Epilepsy; migraine prevention

Documented research summary

CBD dose and topiramate concentrations were associated in the open-label expanded-access programme (CLF053/CLF076, overlapping cohorts). Smaller controlled CBD studies show no apparent effect or insufficient topiramate data. In-vitro polytherapy model 40315023 alters CBD clearance but does not allow an isolated quantitative topiramate effect. CNS/cognitive risk plausible; do not quantify clinically from cannabis use disorder treatment or animal memory effects.

Uncertainties and limitations

Does not establish safety for less-studied cannabinoids or untested formulations/doses.

Do not infer clinical dosage from preclinical effects or enzyme hypotheses.

Separately recorded findings

4 separately recorded findings. Each statement applies to its documented study context.

CBD – clinical signals

Finding ID: B0053

Type of result: Positive finding / indication

Observation: Serum concentrations ↑; p=0.0003.

Mechanism: Mechanism uncertain

Study type: Observational study

Context studied: n=32; total.

Clinical interpretation: Clinical significance unclear

Limitations and uncertainties: Association; CL20 context/limitations.

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]

CBD – clinical signals

Finding ID: B0076

Type of result: Positive finding / indication

Observation: Concentration increase associated with CBD dose.

Mechanism: Mechanism uncertain

Study type: Open-label observational study

Context studied: 81 overall; children/adults.

Clinical interpretation: Unclear

Limitations and uncertainties: Consider CL20 as a later analysis; not an independent replication.

Original sources for this finding: Interactions between cannabidiol and commonly used antiepileptic drugs [CL21]

Cannabis/THC (use) – clinical signals

Finding ID: B0366

Type of result: Clinical signals

Observation: In the ecological momentary assessment substudy abstract, topiramate was associated with a lower subjective high; the indirect effect through the reduced high on daily cannabis smoked was significant. Indirect effects through other subjective responses were not significant.

Mechanism: Pharmacodynamic change in subjective cannabis effects.

Study type: Secondary analysis of a randomised pharmacotherapy study

Context studied: 40 adolescents/young adults aged 15–24 during cannabis use; momentary subjective ratings and amount used.

Clinical interpretation: No safety or interaction-dose evidence

Limitations and uncertainties: Non-standardised cannabis amount, not an individual cannabinoid; secondary analysis, full-text access failed. Do not equate cannabis use disorder treatment outcomes with a pharmacokinetic interaction.

Original sources for this finding: Using Ecological Momentary Assessment to Identify Mechanisms of Change: An Application From a Pharmacotherapy Trial With Adolescent Cannabis Users. [C_PR_29553345]

CBD – laboratory and animal studies

Finding ID: B0367

Type of result: Preclinical evidence

Observation: CBD attenuated topiramate-induced memory deficits in the rat model; NMDA/CREB/BDNF investigated.

Mechanism: Preclinical pharmacodynamic interaction in memory parameters.

Study type: Animal experiment

Context studied: Topiramate 50–100 mg/kg and CBD 20/40 mg/kg intraperitoneally; abstract evaluated.

Clinical interpretation: No human dose can be inferred

Limitations and uncertainties: No clinical confirmation; full text inaccessible through the DOI.

Original sources for this finding: Ameliorative Effect of Cannabidiol on Topiramate-Induced Memory Loss: The Role of Hippocampal and Prefrontal Cortical NMDA Receptors and CREB/BDNF Signaling Pathways in Rats. [C_PR_37814133]

References and access status

[C_LABEL_D0051] TOPAMAX (TOPIRAMATE) TABLET, COATED TOPAMAX (TOPIRAMATE) CAPSULE, COATED PELLETS [JANSSEN PHARMACEUTICALS, INC.]

Original source / bibliographic reference

Authors: JANSSEN PHARMACEUTICALS, INC.

Year: 2026

Source type: US Structured Product Label

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

Bibliographic attribution or source identity cross-checked.

[CA_P_40315023] Cannabidiol metabolism in vitro: the role of antiseizure medications and CYP2C19 genotypes.

Original source / bibliographic reference

Authors: Jaisupa N, Ashton M, Birgersson S.

Year: 2025

Source type: Journal Article

DOI: 10.1080/00498254.2025.2498696

PMID: 40315023

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)

[C_PR_37814133] Ameliorative Effect of Cannabidiol on Topiramate-Induced Memory Loss: The Role of Hippocampal and Prefrontal Cortical NMDA Receptors and CREB/BDNF Signaling Pathways in Rats.

Original source / bibliographic reference

Authors: Aghamiri H, Jafari-Sabet M, Hoormand M.

Year: 2024

Source type: Primary source, abstract read

DOI: 10.1007/s11064-023-04041-4

PMID: 37814133

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)

[C_PR_29553345] Using Ecological Momentary Assessment to Identify Mechanisms of Change: An Application From a Pharmacotherapy Trial With Adolescent Cannabis Users.

Original source / bibliographic reference

Authors: Treloar Padovano H, Miranda R.

Year: 2018

Source type: Primary source, abstract read

DOI: 10.15288/jsad.2018.79.190

PMID: 29553345

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

PubMed Central – archived text

DOI – publisher access (access restrictions may apply)

[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.

[CL21] Interactions between cannabidiol and commonly used antiepileptic drugs

Original source / bibliographic reference

Authors: Gaston TE; Bebin EM; Cutter GR; Liu Y; Szaflarski JP; UAB CBD Program

Year: 2017

Source type: Open-label observational study

DOI: 10.1111/epi.13852

PMID: 28782097

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