Smoking while taking bupropion is not medically dangerous on its own, and in fact, most people are expected to keep smoking for the first week or two after starting the medication. Bupropion is typically begun one to two weeks before a planned quit date precisely because it needs time to build up in your system. What changes once it kicks in is how smoking feels: cigarettes become less satisfying, cravings weaken, and the reward you normally get from nicotine starts to fade. That shift in experience is the whole point of the drug, and understanding what is actually happening in your brain helps explain both why you can smoke safely during that overlap period and why continuing to smoke indefinitely would undermine the treatment.
Why You Start Bupropion Before You Quit
Bupropion takes about a week to reach steady levels in your blood, so doctors have you begin taking it while you are still smoking. The standard approach sets a target quit date roughly one to two weeks after your first dose. During that run-in period, you are not doing anything wrong by smoking. In fact, there is evidence that a longer pre-quit period on the medication works better. A clinical trial comparing an extended four-week pre-quit phase to the standard one-week phase found that people in the longer group cut down their smoking rate more quickly, reported less craving, and achieved higher abstinence rates: about half of the extended group stayed quit versus roughly a third of the standard group.1PubMed Central. Does Extended Pre Quit Bupropion Aid in Extinguishing Smoking Behavior? The drug appears to gradually loosen the grip of nicotine on your reward system, so each cigarette you smoke in those early days reinforces the habit a little less than the one before.
How Bupropion Changes the Way Smoking Feels
Bupropion works differently from most antidepressants. It has no effect on serotonin. Instead, it weakly blocks the reuptake of dopamine and norepinephrine, two brain chemicals involved in motivation, pleasure, and alertness.2PubMed Central. Bupropion Mediated Effects on Depression, Attention Deficit Hyperactivity Disorder, and Smoking Cessation On top of that, bupropion acts as an antagonist at nicotinic acetylcholine receptors, which are the same receptors that nicotine from cigarettes binds to.3PubMed. How does bupropion work as a smoking cessation aid? By partially blocking those receptors, the drug blunts the rush you would normally feel from a cigarette. Researchers believe this receptor-blocking effect may help prevent relapse by making nicotine less rewarding, though it probably does not stop you from wanting to smoke acutely in the moment.
The dopamine piece matters separately. When you quit smoking, your brain suddenly loses a major source of dopamine stimulation. That drop is what makes early withdrawal feel so flat and miserable. Because bupropion props up dopamine levels on its own, it takes the edge off that crash. So the drug works on two fronts: it softens the blow of quitting by replacing some of the lost dopamine, and it dulls the payoff of any cigarette you do smoke by blocking nicotine’s usual entry point.
A head-to-head trial confirmed this in practice. When participants smoked their first cigarette after a target quit date, those on bupropion rated the cigarette as less satisfying and less psychologically rewarding than participants on placebo.4PubMed. Effect of varenicline and bupropion SR on craving, nicotine withdrawal symptoms, and rewarding effects of smoking during a quit attempt Many people describe it as feeling like the cigarette just does not “hit” the way it used to. That underwhelming experience makes it psychologically easier to keep not smoking.
Common Side Effects to Watch For
The side effects you experience on bupropion come from the drug itself, not from the interaction of the drug with cigarettes. In clinical trials at the standard dose, the most frequently reported issues were insomnia, headache, dry mouth, nausea, and anxiety. Of those, only insomnia and dry mouth showed up significantly more often than in people taking a placebo. Anxiety and insomnia can also be symptoms of nicotine withdrawal, so teasing apart what is drug-related versus withdrawal-related is not always straightforward.5Drugs / Springer. Tolerability and safety of sustained-release bupropion in the management of smoking cessation In a large trial, roughly one in nine people on bupropion stopped taking it because of side effects, mostly insomnia and headache.6PubMed. A Controlled Trial of Sustained-Release Bupropion, a Nicotine Patch, or Both for Smoking Cessation
One side effect people worry about is seizures. The risk exists but is genuinely small. In clinical trials of the sustained-release formulation used for smoking cessation, no seizures were reported at all. Post-marketing surveillance in the United Kingdom found seizures at a rate of fewer than one in a thousand patients, and those cases clustered among people who already had a known predisposition, such as a history of seizures or an eating disorder.7Mayo Clinic Proceedings. Bupropion Sustained Release for Treatment of Tobacco Dependence – Section: ADVERSE EFFECTS OF BUPROPION SR The risk goes up with higher doses and with the older immediate-release formulation, which is why doctors prescribe the sustained-release version and cap the dose. Certain other medications can also lower the seizure threshold when combined with bupropion, so your prescriber should review everything you are taking.8PubMed Central. The use of bupropion SR in cigarette smoking cessation
What Happens to Your Heart Rate and Blood Pressure
Smoking raises blood pressure and heart rate on its own, and quitting is one of the best things you can do for your cardiovascular system. A reasonable concern is whether adding bupropion complicates that picture. The evidence is reassuring. One study measured blood pressure around the clock in smokers using bupropion, a nicotine patch, or the combination, and found that while there were some short-term blood pressure elevations right after stopping smoking, 24-hour monitoring showed no significant differences overall.9PubMed. Acute effects of pharmacotherapies in blood pressure in normotensive moderate smokers A larger trial comparing bupropion, varenicline, and nicotine patches found no meaningful differences in blood pressure, heart rate, or body weight across treatment groups at 12, 24, or 52 weeks.10JAMA Internal Medicine. Cardiovascular Safety of Varenicline, Bupropion, and Nicotine Patch in Smokers A separate study in patients with existing cardiovascular disease or high risk scores also found no increase in average blood pressure or heart rate with any of the smoking cessation drugs, alone or in combination.11PubMed Central. Influence of smoking cessation drugs on blood pressure and heart rate in patients with cardiovascular disease or high risk score: real life setting
If You Slip Up and Smoke After Your Quit Date
One of the biggest fears during a quit attempt is that a single cigarette will send you spiraling back to your old habit. The relationship between a slip and a full relapse while on bupropion is more complicated than you might expect. Bupropion slows down the progression from first lapse to regular smoking. A study analyzing lapse patterns during a clinical trial found that bupropion was associated with slower lapse rates for both men and women during the active treatment phase, and helped women recover from a lapse more quickly than they would have on placebo.12Nicotine & Tobacco Research. Recurrent Event Analysis of Lapse and Recovery in a Smoking Cessation Clinical Trial Using Bupropion
However, a separate analysis of the same kind of data found something more nuanced. While bupropion clearly helped people smoke less overall, there was no strong evidence that it worked by preventing a single slip from snowballing into full relapse. In other words, if you did lapse, the drug did not seem to break the chain between that lapse and eventual failure any better than placebo did.13Nicotine & Tobacco Research. Do small lapses predict relapse to smoking behavior under bupropion treatment? The practical upshot: bupropion helps you go longer without smoking in the first place, but it is not a safety net that makes a slip harmless. If you do smoke a cigarette, do not treat it as proof that the medication failed. Get back on track, because the overall effect of the drug is still working in your favor.
How Bupropion Compares to Other Options
Bupropion is effective, but it is not the strongest smoking cessation drug available. Varenicline (sold as Chantix or Champix) consistently outperforms it. In a randomized trial, continuous abstinence rates through week 52 were about 23% for varenicline versus roughly 15% for bupropion and 10% for placebo.14JAMA. Efficacy of Varenicline, an α4β2 Nicotinic Acetylcholine Receptor Partial Agonist, vs Placebo or Sustained-Release Bupropion for Smoking Cessation A meta-analysis described varenicline as increasing abstinence by about 124% compared to placebo and about 22% compared to bupropion.15PubMed Central. Varenicline, smoking cessation, and neuropsychiatric adverse events
That said, bupropion has some advantages. It doubles as a treatment for depression, making it a natural fit for smokers who also have mood issues. It also tends to produce less nausea than varenicline. And combining bupropion with nicotine replacement therapy can boost short-term results. A meta-analysis found that the combination improved abstinence at the end of treatment by about 35% compared to bupropion alone, though the advantage faded to a non-significant difference at six months or longer.16PubMed. Efficacy of combined nicotine replacement therapy (NRT) and bupropion compared to bupropion alone for smoking cessation: a systematic review and meta-analysis An early landmark trial found 12-month abstinence rates of about 36% for combined bupropion and nicotine patch versus 30% for bupropion alone, both far better than the 16% for patch alone or placebo.6PubMed. A Controlled Trial of Sustained-Release Bupropion, a Nicotine Patch, or Both for Smoking Cessation
Weight Gain and Bupropion
Many smokers avoid quitting because they fear gaining weight, and that fear is not irrational. The average person who quits smoking gains several kilograms over the following months. Bupropion appears to limit this. In one dose-ranging trial, people who stayed abstinent on the highest dose of bupropion gained about 1.5 kg on average, compared to nearly 3 kg in the placebo group.17PubMed. A comparison of sustained-release bupropion and placebo for smoking cessation The effect seems to be a genuine drug effect rather than simply a result of people smoking less, since the comparison was among people who were all continuously abstinent.
That said, the weight benefit is modest and may not last forever once the medication is stopped. A trial in weight-concerned women smokers found that among those who stayed abstinent, the average weight gain by three months was around 5 kg regardless of which group they were in, suggesting that once quitting is well-established, the weight trajectory may converge.18PubMed Central. Bupropion and Cognitive Behavioral Therapy for Weight-Concerned Women Smokers Still, the early blunting of weight gain can be psychologically important during the fragile first weeks of a quit attempt.
Smoking Cessation With Depression or Other Psychiatric Conditions
Because bupropion is also prescribed as an antidepressant, it occupies a unique niche among smoking cessation drugs for people with mood disorders. A large secondary analysis of over 6,600 participants found that the risk of neuropsychiatric adverse events did not differ by medication within groups of people who had current or past major depression, compared to the non-psychiatric group.19PubMed. Effects of Varenicline, Bupropion, Nicotine Patch, and Placebo on Treating Smoking Among Persons With Current or Past Major Depressive Disorder People with depression did have higher overall rates of neuropsychiatric side effects regardless of which treatment they received, but bupropion was no worse than patches or placebo in that regard. Quit rates in the depression group were somewhat lower across all treatments, with bupropion producing continuous abstinence in about 23% versus roughly 13% on placebo.20PubMed Central. The effects of varenicline, bupropion, nicotine patch, and placebo on smoking cessation among smokers with major depression
For people with schizophrenia, who smoke at extremely high rates, bupropion has shown particular promise. A systematic review found that participants on bupropion were roughly five times as likely to maintain continuous abstinence as those on placebo, and none of the trials found that bupropion worsened positive symptoms, negative symptoms, or depressive symptoms.21PubMed Central. Pharmacotherapy for Smoking Cessation in Schizophrenia: A systematic review Individual small trials have even found improvements in negative symptoms during bupropion treatment.22PubMed. A placebo controlled trial of bupropion for smoking cessation in schizophrenia These are small studies, but the consistency of the safety signal is encouraging for a population that is often excluded from or underserved by cessation treatment.
Drug Interactions Worth Knowing About
Bupropion is broken down in the liver by an enzyme called CYP2B6, and it itself blocks a different enzyme called CYP2D6. That second part matters because many common medications rely on CYP2D6 to be cleared from the body. If you are taking a beta-blocker like metoprolol, certain antidepressants, or antipsychotic medications, bupropion can slow their breakdown and effectively increase their levels in your blood. Doctors typically start those other drugs at a lower dose when bupropion is on board.23Australian Prescriber. Smoking and drug interactions – Section: Drugs for nicotine dependence
Smoking itself also affects drug metabolism, but through a completely different pathway. The polycyclic aromatic hydrocarbons in cigarette smoke ramp up CYP1A2 activity, which means that when you quit smoking, drugs metabolized by CYP1A2 can suddenly spike in your blood because the enzyme that was chewing through them so efficiently has slowed down. Common medications affected include certain antipsychotics, theophylline, and caffeine. This is not a bupropion interaction per se, but it is a quitting-smoking interaction that can catch people off guard. If you are on medications that go through CYP1A2, your doctor may need to adjust doses as your cigarette intake drops.
Bupropion and Electronic Cigarettes
A growing question is whether bupropion can help people switch from combustible cigarettes to e-cigarettes rather than quitting nicotine entirely. One pilot study explored a novel approach using bupropion combined with the anti-seizure medication zonisamide to help smokers transition to electronic nicotine delivery systems. About a third of participants achieved confirmed abstinence from combustible cigarettes by the end of the treatment period.24PubMed. Bupropion/zonisamide combination to assist smokers to switch from combustible cigarettes to electronic nicotine delivery systems (ENDS) This is preliminary data from a small, uncontrolled study, so it is far from definitive. But the concept of pairing short-term medication with longer-term nicotine substitution is an active area of interest, especially for heavy smokers who find cold-turkey abstinence unrealistic.
Bupropion During Pregnancy
Smoking during pregnancy carries well-established risks, but whether bupropion is safe for the baby is a harder question. A meta-analysis pooling available evidence found no major positive or negative effect on rates of congenital abnormalities, birth weight, or premature birth, though the authors emphasized that the available evidence was of poor quality.25Nicotine & Tobacco Research. Systematic Review and Meta-Analysis to Assess the Safety of Bupropion and Varenicline in Pregnancy A placebo-controlled trial in pregnant smokers found no significant differences in gestational age at birth, birth weight, head circumference, or Apgar scores between bupropion and placebo groups.26PubMed Central. Placebo-Controlled Trial of Bupropion for Smoking Cessation in Pregnant Women A population-based cohort study also found no increased risk of adverse perinatal events among bupropion-exposed women.27PubMed Central. Use of smoking cessation pharmacotherapies during pregnancy is not associated with increased risk of adverse pregnancy outcomes: a population-based cohort study
The honest state of the science here is that nothing alarming has turned up, but the data is thin enough that no one can guarantee absolute safety. For pregnant smokers who cannot quit through behavioral methods alone, the risk-benefit calculation involves weighing the known harms of continued smoking against the less-certain but apparently low risks of the medication. That is a conversation to have with a prenatal care provider rather than a decision to make based on an internet article.