Last reviewed
Smoking and psychiatric medications: why your dose may need to change
Cigarette smoke speeds up how fast the body clears some psychiatric medications. Quitting can raise levels, so tell your prescriber.
Earl Johns, MSN, PMHNP-BC
Board-certified psychiatric nurse practitioner and founder of Wellthy Psychiatry & Wellness
✓ Medically reviewed by Earl Johns, MSN, PMHNP-BC
Photos are illustrative and don’t show actual patients.
Many people don’t know that smoking can change how their psychiatric medications work. The effect comes from chemicals in burning tobacco smoke, not from nicotine itself.
How smoke affects medication levels
Tar and other compounds in cigarette smoke speed up a liver enzyme called CYP1A2. That enzyme breaks down several psychiatric medications, so people who smoke often have lower levels in their blood.
Medications most affected
Clozapine and olanzapine are the best-known examples. Fluvoxamine, duloxetine and some other medications are also affected. Caffeine is cleared faster too, which is why some smokers drink more coffee.
What happens when you quit
When you stop smoking, the enzyme slows back down over about a week or two, and medication levels can rise. With clozapine in particular, this can cause serious side effects if the dose isn’t adjusted. Caffeine can also hit harder, causing jitteriness or poor sleep.
Nicotine replacement is different
Nicotine patches, gum and lozenges don’t contain the smoke compounds that speed up the enzyme, so they don’t have the same effect on medication levels.
Tell your prescriber
Let your prescriber know before you quit, cut back sharply or start smoking again. They may want to check levels or adjust your dose.
A gentle next step
Wellthy Psychiatry offers judgment-free, LGBTQ+ affirming care by telehealth across California. A free 15-minute phone consult is an easy way to see if we’re a good fit.
This article is for general education and isn’t medical advice. If you’re in crisis, call or text 988, the Suicide & Crisis Lifeline, or call 911.
About the author
Earl Johns, MSN, PMHNP-BC
Board-certified psychiatric nurse practitioner · UCSF-trained · Founder of Wellthy Psychiatry & Wellness
Earl provides LGBTQ+ and neurodivergent-affirming psychiatric care, blending medication management, therapy and whole-person approaches. His background includes inpatient psychiatry and community mental health at Glenn County Behavioral Health and Equity Health, a federally qualified health center. He sees clients in San Francisco and by telehealth across California.
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