Which medications interact with psychedelics, how long the washout windows are, and the red-flag combinations that send people to the ER.
Most classic psychedelics work on serotonin receptors. So do many common prescriptions — SSRIs, SNRIs, MAOIs, lithium, tramadol, and the surgical dye methylene blue. Stacking them in the wrong order can cause serotonin syndrome, hypertensive crisis, seizures, or a blunted experience that wastes the session.
Psychedelic medication safety is the practice of reviewing every drug and supplement you take and timing washouts so the session is safe and effective. Every legitimate clinical trial and every reputable retreat does this screening. You should too.
The windows below are typical for clinical trials and reputable retreats. They are guidelines, not rules. Your prescriber may recommend a different timeline based on your dose, duration of use, and reason for the medication.
| Medication class | Example drugs | Typical washout | Risk level |
|---|---|---|---|
| SSRIs (short half-life) | Sertraline, citalopram, escitalopram, paroxetine | 2–4 weeks | Medium |
| SSRI — fluoxetine (Prozac) | Fluoxetine | 6 weeks (long half-life) | Medium |
| SNRIs | Venlafaxine, duloxetine | 2–4 weeks | Medium |
| MAOIs | Phenelzine, tranylcypromine, selegiline, linezolid | 6 weeks | High |
| Lithium | Lithium carbonate | Trials typically exclude | High |
| Tricyclics (TCAs) | Amitriptyline, nortriptyline | 2 weeks | Medium |
| Atypical antidepressants | Bupropion (Wellbutrin), mirtazapine | 2 weeks (case by case) | Lower |
| Methylene blue | Methylene blue nootropic | 2 weeks | High |
| Tramadol | Tramadol | 1–2 weeks | High |
| Stimulants | Adderall, Vyvanse, Ritalin | 3–7 days | Medium |
| Sleep aids | Zolpidem, trazodone | 3 days before session | Lower |
| Cannabis | THC products | 3 days before session | Lower |
| Alcohol | Any | 3 days before session | Lower |
SSRIs are the most common medication people ask about. They blunt the psilocybin experience and may slightly raise the theoretical risk of serotonin issues, though documented severe events are rare.
Clinical trials almost always require a washout. The exact window depends on the drug's half-life:
The decision to stop an SSRI for a psychedelic is a clinical one. Some patients should not stop. If you cannot stop, ketamine therapy generally remains an option because it works on glutamate, not serotonin.
MAOIs are the highest-risk class. The interaction with MDMA can be fatal. The interaction with ayahuasca is automatic, because ayahuasca itself is an MAOI brew.
Standard washout for prescription MAOIs is 6 weeks. The list includes:
Methylene blue deserves its own line. It is sold online as a "nootropic" and is increasingly common. The FDA has issued safety communications because of MAOI-related serotonin syndrome cases.
Lithium plus a classic psychedelic (psilocybin, LSD, DMT) has been linked to seizures in multiple case reports. The mechanism is not fully understood. Clinical trials treat lithium as a hard exclusion, and integration clinicians treat it the same way.
If you take lithium for bipolar disorder, do not plan a psychedelic session without a long, careful conversation with your prescribing psychiatrist. Most experts recommend not doing one at all on lithium.
Tramadol is serotonergic and lowers the seizure threshold, which makes it especially risky with MDMA or ayahuasca. Other opioids (oxycodone, hydrocodone, morphine) are less serotonergic but still depress breathing — a concern with ibogaine in particular.
Stop tramadol 1–2 weeks before a serotonergic psychedelic, under your prescriber's care.
ADHD stimulants (amphetamine salts, lisdexamfetamine, methylphenidate) raise heart rate and blood pressure. Combining with MDMA or 5-MeO-DMT stacks cardiovascular load. Most trials require 3–7 days off before dosing.
A personal or family history of psychosis is a standard exclusion in almost every classic-psychedelic trial protocol. Psilocybin, LSD, and 5-MeO-DMT can trigger or worsen psychotic symptoms in someone predisposed to schizophrenia or schizoaffective disorder. That risk stays even when a program only screens for current symptoms. A program that skips the question is skipping a standard safety screen.
Borderline personality disorder (BPD) sits in a gray zone. Many trials still exclude it outright. The emotional intensity and dissociation a psychedelic session can bring on may be harder to contain in someone who already struggles with affect regulation. Self-harm risk is the specific concern screeners raise. Some MDMA-assisted-therapy research overlaps with BPD's trauma roots, but that overlap has not produced a validated BPD-specific protocol yet. Anyone with a BPD diagnosis should raise it during screening. Expect extra caution from the screener. Full exclusion is not automatic.
Alcohol use disorder (AUD) is the exception on this list. It is an active treatment target studied directly, beyond a plain screening flag. A 2022 randomized trial run out of NYU Langone Health and the University of New Mexico gave psilocybin-assisted therapy to adults with AUD. Heavy drinking days dropped significantly more than in the diphenhydramine-controlled comparison group over 32 weeks. 6 That result is specific to a supervised trial setting with trained facilitators. It is not a reason to self-treat drinking with mushrooms outside one.
Pregnant and breastfeeding people are excluded from every MDMA, psilocybin, and ibogaine clinical trial, so none of those substances have pregnancy or breastfeeding safety data. Ketamine is the exception. LactMed, the National Institutes of Health's database on drug transfer into breast milk, has no entry for psilocybin or MDMA at all. Its ketamine entry draws on mothers who received the drug during cesarean delivery. LactMed reports the drug crosses into milk at a relative infant dose under 1%. The babies tracked in those studies showed no reported effect. That data covers one anesthetic dose in a hospital. It says nothing about repeated ketamine therapy for depression, and the manufacturer's own nursing guidance covers anesthetic use only.
Pregnancy carries a different risk than breastfeeding, because a drug can affect a developing fetus without ever reaching breast milk in a meaningful amount. MDMA and the classic psychedelics raise heart rate and blood pressure, and ibogaine adds a cardiac risk covered in the ibogaine guide. That cardiovascular load affects both the pregnant person and the fetus. None of it has been studied in pregnant people, because every trial protocol excludes them.
If you are pregnant, trying to conceive, or breastfeeding, say so during screening for any psychedelic session, clinic, retreat, or trial. A program that never asks about pregnancy status is skipping a standard safety question. Ask why, or look for one that does.
| Psychedelic | Main interaction concerns | Practical notes |
|---|---|---|
| Psilocybin | SSRIs (blunting), lithium (seizure), MAOIs (theoretical) | Most studied. Standard 2–6 week SSRI washout. |
| MDMA | MAOIs (fatal), SSRIs (blunting + risk), tramadol | Cardiac screening required. Hard contraindication with MAOI. |
| Ayahuasca | SSRIs, SNRIs, MAOIs, tramadol, methylene blue, tyramine foods | The brew itself is an MAOI. Strictest washout list. |
| 5-MeO-DMT | SSRIs (blunting), MAOIs (intensifies), stimulants | Short experience but high cardiovascular load. |
| Ibogaine | QT-prolonging drugs, cardiac risk, opioids | Cardiac screening (EKG, magnesium) is mandatory. |
| Ketamine | Benzodiazepines (blunting), uncontrolled hypertension | Fewest serotonergic interactions; usable on most antidepressants. |
Benzodiazepines (Xanax/alprazolam, Klonopin/clonazepine, Ativan/lorazepam) are the interaction that matters most for ketamine specifically — they blunt ketamine's antidepressant effect by dampening the same glutamate signaling ketamine relies on, so most programs ask patients to avoid taking a benzodiazepine dose the day of a session. SSRIs (Zoloft/sertraline, Lexapro/ escitalopram, Prozac/fluoxetine) are generally compatible with ketamine — unlike the multi-week SSRI washout this page documents for psilocybin, MDMA, and ayahuasca, ketamine has the fewest serotonergic interactions of the psychedelics on this page and is routinely used alongside an existing SSRI or SNRI. Always confirm your specific combination with your prescriber; this is a general pattern, not a substitute for a medication review.
Most clinical trials require a 2–6 week SSRI washout before psilocybin dosing. SSRIs can blunt the psilocybin experience and may raise theoretical risk of serotonin issues, though severe events are rare. Never stop an SSRI without your prescriber. Coordinate any taper with the doctor who prescribed it.
Mixing MDMA with a monoamine oxidase inhibitor (MAOI) is potentially fatal. The combination can cause severe hyperthermia, hypertension, and serotonin syndrome. MAOI examples include phenelzine, tranylcypromine, selegiline, and the antibiotic linezolid. MDMA trials exclude anyone on an MAOI within the past 6 weeks.
Multiple case reports link lithium plus a classic psychedelic (psilocybin, LSD) to seizures. The mechanism is not fully understood. Clinical trials exclude patients on lithium, and integration clinicians treat lithium as a hard contraindication for now.
No. Methylene blue is a potent reversible MAOI. Combining it with a serotonergic psychedelic raises serotonin syndrome risk. Most facilitators ask you to stop methylene blue at least 2 weeks before a ceremony. Ask your prescriber for an exact washout window.
Ayahuasca contains MAOIs (harmine, harmaline), so the SSRI risk is more serious than with psilocybin. Most retreats require a 4–6 week SSRI washout for short-half-life SSRIs and 6+ weeks for fluoxetine (Prozac). Always involve your prescriber in any taper.
Yes, but differently than the MAOI combination above. SSRIs occupy the same serotonin transporter MDMA needs to trigger its effects, so taking MDMA at a therapeutic SSRI dose typically blunts or blocks the experience rather than causing acute danger. Clinical MDMA-assisted therapy protocols require an SSRI washout, generally 2 to 5 weeks depending on the specific drug's half-life, before a dosing session. The bigger risk is combining MDMA with an SSRI you have just stopped or tapered incorrectly, which can still raise serotonin syndrome risk. Never stop an SSRI without your prescriber, and coordinate any taper with the doctor who prescribed it.
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