Cannabis Exposure Interactions with Nicotine Effects: Insights from Randomized Studies
Clinical Takeaway
Recent cannabis use does not significantly alter the acute subjective effects of intravenous nicotine in tobacco smokers. This finding suggests that recent cannabis exposure may not impact nicotine cessation outcomes directly through pharmacodynamic interactions.
#10 Recent cannabis exposure and acute nicotine effects: insights from randomized, double-blind, placebo-controlled intravenous nicotine studies.
Citation: Costa Gabriel P A et al.. Recent cannabis exposure and acute nicotine effects: insights from randomized, double-blind, placebo-controlled intravenous nicotine studies.. The international journal of neuropsychopharmacology. 2026. PMID: 42189934.
Design: 5 Journal: 2 N: 1 Recency: 3 Pop: 2 Human: 1 Risk: -2
- Preclinical only
Abstract: OBJECTIVE: Cannabis-nicotine co-use is common and may affect cessation outcomes, yet whether recent cannabis exposure alters nicotine’s acute effects in humans remains unclear. We examined whether recent, non-daily cannabis exposure modulates the acute subjective effects of intravenous (IV) nicotine. METHODS: We pooled data from 2 randomized, double-blind, placebo-controlled studies using IV nicotine to isolate nicotine’s pharmacodynamics in adults who smoke tobacco cigarettes (N = 60). Participants completed 3 sessions (placebo, 0.1 mg, 0.2 mg nicotine/70 kg). Recent cannabis exposure was defined a priori (past-30-day use with positive urine 11-nor-9-carboxy-delta-9-tetrahydrocannabinol vs no past-30-day use with negative screen). Primary outcomes were peak Drug Effects Questionnaire (DEQ) composites-stimulatory, pleasurable, aversive-within 10 minutes post-infusion. Secondary outcomes included nicotine self-administration behavior (proportion of nicotine choices) and cardiovascular responses (heart rate, blood pressure). Linear mixed-effects models included dose, cannabis exposure, sex, and FTND. RESULTS: Nicotine increased all DEQ domains dose-dependently (P < .0001). Aversive effects showed a significant dose x cannabis exposure interaction (χ2 = 13.31, P = .001): participants with recent cannabis exposure reported greater aversive responses at 0.2 mg (Cohen's d' = 0.83), with minimal between-group differences at placebo/0.1 mg. Nicotine self-administration did not differ by cannabis exposure status, and no dose x cannabis exposure interactions were observed for cardiovascular responses. CONCLUSIONS: Recent, non-daily cannabis exposure is thus associated with selectively greater aversive responses to a clinically relevant IV nicotine dose, without differential cardiovascular reactivity or altered nicotine choice. These findings support a shift in the aversive limb of nicotine's dose-response and inform mechanistic and clinical studies on how cannabis exposure sh
What This Study Teaches Us
When people with recent cannabis use receive IV nicotine, they report stronger unpleasant effects at higher doses compared to those without recent cannabis exposure. Nicotine still worked the same way on blood pressure and heart rate, and people didn’t choose it differently, so the cannabis interaction appears selective to how nicotine feels rather than its core pharmacology.
Why This Matters Clinically
If cannabis genuinely dampens nicotine’s rewarding effects while amplifying its aversiveness, this could reshape how we counsel people trying to quit smoking, especially those using both substances. It also suggests cannabis-nicotine interactions are more nuanced than simple potentiation or antagonism, which matters for treatment planning in co-users.
Study Snapshot
| Study Design | Pooled analysis of 2 randomized, double-blind, placebo-controlled crossover studies with IV nicotine dosing |
| Population | N=60 adults who smoke tobacco cigarettes; stratified by recent cannabis exposure (past-30-day use with positive THC metabolite screen vs. no use with negative screen) |
| Intervention | Intravenous nicotine: placebo, 0.1 mg/70 kg, or 0.2 mg/70 kg; 3 sessions per participant |
| Primary Outcome | Peak Drug Effects Questionnaire (DEQ) composite scores for stimulatory, pleasurable, and aversive effects within 10 minutes post-infusion |
| Key Result | Significant dose x cannabis exposure interaction for aversive effects: recent cannabis users reported greater aversiveness at 0.2 mg nicotine (Cohen’s d’=0.83); no interaction for self-administration behavior or cardiovascular responses |
Where This Paper Deserves Skepticism
The sample is modest (N=60 total, split by cannabis exposure), and the definition of ‘recent’ cannabis use is past-30-day with a urine screen, which tells us about exposure but not frequency, dose, or THC:CBD ratios. The study looked only at acute subjective effects in a controlled IV setting, which is far removed from real-world smoking behavior and long-term cessation. We don’t know whether this pattern holds in daily cannabis users or whether it matters clinically for quit attempts.
Dr. Caplan’s Take
This is interesting because it’s tight methodology applied to a real clinical question. The finding that cannabis amplifies nicotine’s aversive kick without changing self-administration choices or heart rate is specific enough to be credible, but it’s also preliminary. I’d want to see this replicated in a larger sample and ideally in people actually trying to quit. Right now it tells us something real is happening at the neurochemical level, but I can’t yet tell you whether this helps or hurts cessation outcomes in your patient sitting across from you.
Clinical Bottom Line
Recent cannabis use appears to make nicotine feel worse subjectively (more aversive at higher doses) without changing people’s actual choice to use it or their cardiovascular response. This might open a door for harm reduction or cessation messaging, but we need more evidence before building treatment strategies on it.
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