THC Made Chemotherapy Side Effects Worse in Some Ways, Better in Others

THC combined with the chemotherapy drug irinotecan worsened white blood cell drops in rats but appeared to protect against liver enzyme elevation.

Prester, Ljerka et al.·Chemico-biological interactions·2018·Preliminary EvidenceAnimal StudyAnimal Study
RTHC-01799Animal StudyPreliminary Evidence2018RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Animal Study
Evidence
Preliminary Evidence
Sample
Not reported

What This Study Found

Co-administration of THC with irinotecan in rats caused greater leukopenia than irinotecan alone, but the expected rise in the liver enzyme AST seen with irinotecan alone did not occur in the combination group.

Key Numbers

THC dose was 7 mg/kg orally. Irinotecan dose was 100 mg/kg. Urinary THC metabolite concentrations were higher in the irinotecan + THC group compared to THC-only, suggesting a pharmacokinetic interaction.

How They Did This

Male rats received single-dose irinotecan alone or with repeated oral THC (1, 3, or 7 days). Blood and urine were analyzed for blood counts, liver enzymes, inflammatory markers, and THC metabolites.

Why This Research Matters

Many cancer patients use cannabis to manage chemotherapy side effects. This study suggests THC may have both helpful and harmful interactions with at least one chemo drug, highlighting the need to understand these interactions before combining treatments.

The Bigger Picture

As cannabis use among cancer patients increases, understanding how cannabinoids interact with chemotherapy drugs becomes critical. This study provides early evidence that THC may alter both the effectiveness and toxicity profile of irinotecan.

What This Study Doesn't Tell Us

Animal study using a single chemo drug and relatively high doses. Results may not translate directly to humans. Only male rats were studied. Short follow-up period.

Questions This Raises

  • ?Does THC interact similarly with other chemotherapy drugs?
  • ?Would lower, more clinically relevant THC doses produce the same effects?
  • ?What mechanism drives the protective liver effect versus the worsened blood cell counts?

Trust & Context

Key Stat:
THC metabolite levels were higher when combined with irinotecan, suggesting a pharmacokinetic interaction between the two drugs.
Evidence Grade:
Preliminary - single animal study with a small sample.
Study Age:
Published in 2018. More research has since explored cannabinoid-chemotherapy interactions.
Original Title:
Effects of Δ9-tetrahydrocannabinol on irinotecan-induced clinical effects in rats.
Published In:
Chemico-biological interactions, 294, 128-134 (2018)
Database ID:
RTHC-01799

Evidence Hierarchy

Meta-Analysis / Systematic Review
Randomized Controlled Trial
Cohort / Case-Control
Cross-Sectional / Observational
Case Report / Animal StudyOne case or non-human subjects
This study

Tests effects in animals (usually mice or rats), not humans.

What do these levels mean? →

Frequently Asked Questions

Can you use cannabis while on chemotherapy?

This rat study suggests THC may interact with the chemo drug irinotecan in complex ways - reducing some side effects while worsening others. Human data is limited, and interactions likely vary by drug.

Does THC affect how chemo drugs are processed in the body?

This study found that THC metabolite levels were higher when THC was given alongside irinotecan, suggesting the drugs may affect each other's metabolism.

Read More on RethinkTHC

Cite This Study

RTHC-01799·https://rethinkthc.com/research/RTHC-01799

APA

Prester, Ljerka; Mikolić, Anja; Jurič, Andreja; Fuchs, Nino; Neuberg, Marijana; Lucić Vrdoljak, Ana; Brčić Karačonji, Irena. (2018). Effects of Δ9-tetrahydrocannabinol on irinotecan-induced clinical effects in rats.. Chemico-biological interactions, 294, 128-134. https://doi.org/10.1016/j.cbi.2018.08.009

MLA

Prester, Ljerka, et al. "Effects of Δ9-tetrahydrocannabinol on irinotecan-induced clinical effects in rats.." Chemico-biological interactions, 2018. https://doi.org/10.1016/j.cbi.2018.08.009

RethinkTHC

RethinkTHC Research Database. "Effects of Δ9-tetrahydrocannabinol on irinotecan-induced cli..." RTHC-01799. Retrieved from https://rethinkthc.com/research/prester-2018-effects-of-9tetrahydrocannabinol-on

Access the Original Study

Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.

This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.