Interactions Between Strattera (Atomoxetine) and Marijuana

Pharmacokinetic Considerations

Cannabis and cannabinoids inhibit several cytochrome P450 enzymes, specifically CYP3A4 and CYP2C19, but CYP2D6 inhibition by cannabis is not well-established, suggesting that significant pharmacokinetic interactions are unlikely 1
Cannabis products have highly variable THC and CBD content, making any potential drug interactions unpredictable 1
CBD at higher doses (>300 mg/day) presents risks for hepatotoxicity with dose-related, reversible transaminase elevations 1

Cannabis can cause tachycardia and orthostatic hypotension, particularly with more serious adverse effects 1
The combination of atomoxetine and cannabis may produce additive cardiovascular effects, including increased heart rate and blood pressure instability 2
Cannabis commonly causes dizziness, confusion, somnolence, and dry mouth 2
These overlapping side effect profiles may result in enhanced sedation, confusion, and impaired cognitive function when used together 5
Cannabis may exacerbate psychiatric disorders in vulnerable individuals and is associated with increased risk for developing depressive disorders 1

Assess for enhanced CNS depression: watch for excessive sedation, dizziness, confusion, or impaired coordination 2, 1
Screen for psychiatric symptoms: monitor for mood changes, anxiety, paranoia, or suicidal ideation 1
If cannabis use is ongoing, start atomoxetine at the lower end of the dosing range (40 mg daily) and titrate slowly every 7-14 days 6
Advise patients to start cannabis products at the lowest possible dose and increase slowly with sufficient time between doses to gauge effects 1
Avoid high-fat meals when taking oral cannabis products, as this significantly increases cannabinoid absorption and may exacerbate interactions 1

Strongly advise against driving when feeling the effects of either substance, as cannabis users are more than twice as likely to be involved in motor vehicle crashes 1

CBD can cause hepatotoxicity, particularly at higher doses, requiring consideration of liver function monitoring 1

Do not assume cannabis is benign simply because it may be legal in your jurisdiction; it carries significant cardiovascular and psychiatric risks 2, 1
Do not fail to ask about cannabis use, as patients may not volunteer this information; direct questioning is essential 1
Do not ignore the variable potency of cannabis products; street cannabis and dispensary products can have vastly different THC/CBD ratios 1

Most interaction concerns are based on theoretical considerations and overlapping side effect profiles rather than documented clinical interactions 1