Psilocybin Drug Interactions

Last updated: July 2, 2026 · Reviewed against the editorial policy

Why combinations matter

On its own, psilocybin is low in toxicity.^[1] You can read more on our risks page. But mixing it with some medicines or drugs changes the picture. Some mixes can cause seizures. Others can blunt the trip or push serotonin — a brain chemical — too high. This is why drug mixes may be the single most vital safety topic for anyone who chooses to use.

Psilocybin works mainly on serotonin systems in the brain.^[1] Many common medicines also act on serotonin. That overlap is where most drug mixes come from. The rest of this page covers the drugs that come up most in the research and in real-world reports.

Lithium: the most serious concern

Lithium is a mood stabilizer, often used for bipolar disorder. It has the most worrying record with psychedelics. A review of self-reported cases found that mixing lithium with a classic psychedelic was linked to seizures and other severe harm far more often than mixing with the drug lamotrigine.^[2]

In that review, a large share of lithium-plus-psychedelic reports told of bad outcomes, including seizures and medical emergencies.^[2] These are case reports, not trials, so exact rates are not known. But the signal is strong and the harm is severe. This is why people already know that bipolar disorder rules out psilocybin — see the risks page. Lithium is the reason it matters twice over.

SSRIs and SNRIs

SSRIs and SNRIs are common antidepressants. Examples include sertraline, fluoxetine, escitalopram, and venlafaxine. They raise serotonin levels over weeks of daily use.

Two things tend to happen when someone on a daily SSRI takes psilocybin. First, the psilocybin effect is often blunted or weaker. Long-term SSRI use seems to lower how strongly psilocybin acts, likely through changes in serotonin receptors. Second, there is a concern about too much serotonin, a state called serotonin toxicity or serotonin syndrome. A close review found that the classic serotonin psychedelics carry a low direct risk of serotonin toxicity on their own, because of how they act on receptors.^[3] The bigger, better-known danger comes from other mixes, such as MAOIs, covered next.

MAOIs

MAOIs are a class of antidepressant. They are also found in some plants used for "ayahuasca-style" brews. MAOI stands for monoamine oxidase inhibitor. These drugs block an enzyme that breaks down serotonin and similar chemicals.

When that enzyme is blocked, psilocybin's active form can build up and act more strongly. This boost can make the trip more intense and harder to predict, and it raises the risk of serotonin toxicity.^[3] People who take an MAOI for depression or Parkinson's disease face a mix that is hard to predict and should be treated as high risk.

Tramadol and other seizure-lowering drugs

Tramadol is a prescription painkiller. On its own it can lower the seizure threshold — that means it makes seizures easier to set off — and it also raises serotonin. Those are tramadol's own well-known risks, apart from psilocybin. Because psilocybin also acts on serotonin,^[3] mixing the two is best avoided to be safe. Treat this as a mix to raise with a doctor, not one to test.

Other drugs that lower the seizure threshold deserve the same care. These include bupropion (an antidepressant and stop-smoking aid) and some stimulants. Anyone with a seizure disorder, or on a medicine that affects seizures, is in a higher-risk group.

Stimulants

Stimulants include prescription ADHD medicines, as well as illegal drugs like cocaine and amphetamines. They raise heart rate and blood pressure. Psilocybin already raises both for several hours.^[1] Stacking the two adds strain on the heart.

Stimulants also raise anxiety and unease. That can make a hard trip more likely and harder to handle. If a hard trip does start, our page on difficult experiences shows how a calm setting helps.

Alcohol

Alcohol is a depressant. It dulls judgment and balance, which psilocybin already harms. The two together raise the chance of accidents, falls, and dangerous choices. Alcohol can also make nausea worse. Heavy drinking beforehand is one of the higher-risk mental states listed on our risks page.

Cannabis

Cannabis is very often mixed with psilocybin, but it is not risk-free. Cannabis can sharply raise anxiety and paranoia during a trip. It can also make effects feel stronger and harder to control. For someone prone to panic, cannabis can turn a calm trip into a scary one. People who choose to use often keep cannabis away from psilocybin sessions for this reason. Good set and setting and a sober trip sitter matter more than any add-on.

Interaction summary table

Risk levels below reflect the way and strength of proof in published studies. They are general education, not personal medical advice.

Unfamiliar words on this page are defined in the glossary. For research context, see clinical research.

Never stop your medicine on your own

Some people think they can just pause an antidepressant to "feel more" from psilocybin. This is risky. Stopping a medicine all at once can cause withdrawal, rebound symptoms, or a return of the condition it was treating. That includes a return of depression or suicidal thoughts.

Only a prescribing doctor can safely plan any change to a medicine. If a hard trip or medical problem happens after mixing drugs, get help right away using the contacts below. See also our emergencies page.