The official drug labels set a gap of 5 days to 5 weeks before an MAO inhibitor. Here are the numbers, where they come from, and what to ask any retreat.
There is no single safe number: the official drug labels for common antidepressants set a minimum gap of 5 days to 5 weeks between your last dose and starting an MAO inhibitor (the type of compound in ayahuasca), and most of them say 14 days. Fluoxetine (Prozac) is the outlier, at 5 weeks or more, because it lingers in the body. Do not stop or cut down any medication on your own - talk to the prescriber who knows your history first, because stopping too fast can cause withdrawal symptoms and relapse, and any taper has to be planned and supervised by them.
Here are the numbers, where they come from, and what they can and cannot tell you.
Ayahuasca (yagé) is brewed from the Banisteriopsis caapi vine, which contains the harmala alkaloids harmine and harmaline. These block monoamine oxidase (MAO), the enzyme your body uses to break down serotonin. Callaway and Grob (1998) describe this blockade as lasting "for several hours" after drinking. A 2026 pharmacology study describes harmine as a reversible MAO-A inhibitor (Ribeiro et al., 2026).
Most antidepressants raise serotonin in a different way, by stopping it being taken back up into nerve cells. Put the two together and, in Callaway and Grob's words, you block "two essential pathways for serotonin": the body keeps making it, and can no longer clear it. Too much serotonin can tip into serotonin syndrome.
It is a reaction to too much serotonin activity in the body. The FDA-approved label for lithium describes it as "potentially life-threatening" and lists signs including:
(Source: Lithium Carbonate prescribing information, section 5.6, via DailyMed.)
Here is the part that matters for ceremony: Callaway and Grob point out that the early signs (euphoria or confusion, vomiting, tremor) overlap with what people commonly experience on a normal dose of ayahuasca. That makes a developing reaction harder to spot in the room. They describe a man taking 20 mg of fluoxetine a day who drank about 100 ml of ayahuasca at a ceremony. Within an hour he had tremors, sweating, shivering and confusion, collapsed outside, and stayed incapacitated with heavy sweating, tremors, nausea and vomiting for several hours. He recovered without treatment after about four hours. The authors are clear that serious cases need fast emergency treatment, and they cite published fatal cases from combining an MAO-A inhibitor with serotonergic antidepressants (Neuvonen et al., 1993, five fatal cases after overdoses of moclobemide plus clomipramine).
How common is it? Honestly, nobody knows. A 2024 systematic review of drug interactions with classic psychedelics found only one ayahuasca study, and says that "except for a few case reports, no serious adverse drug events were described" (Halman et al., 2024). A short list of reported cases does not prove the combination is safe. Controlled studies of this interaction in people have not been done. A 2026 computer-modelling study predicted that fluoxetine and paroxetine increase blood levels of harmine and moderately increase DMT, and its authors call the interaction "clinically relevant" (Ribeiro et al., 2026). That is a simulation, not a human trial.
The numbers below come from the official US prescribing information for each drug (FDA labels on DailyMed). They describe the minimum gap after the last dose before starting a pharmaceutical MAO inhibitor antidepressant. No regulator has published a washout figure written specifically for ayahuasca. These label figures are the closest official benchmark, and the people who prescribe your medication will know them.
SSRI: fluoxetine (Prozac): At least 5 weeks. Fluoxetine and its active metabolite norfluoxetine leave the body slowly; the label gives norfluoxetine an elimination half-life of 4 to 16 days. Callaway and Grob (1998) note active metabolites "may remain up to five weeks". Source: Prozac label, sections 2.9 and 4.1; Callaway & Grob 1998
SSRIs: most others (Zoloft (sertraline), Lexapro (escitalopram), Celexa (citalopram), Paxil CR (paroxetine)): At least 14 days. Blocks serotonin reuptake. Combined with an MAO inhibitor, this is the classic serotonin syndrome pairing. Older harm-reduction guidance gave 2 to 3 weeks (Savinelli & Halpern, 1995). Source: Zoloft, Lexapro, Celexa and Paxil CR labels
Other serotonergic antidepressants (Viibryd (vilazodone); Trintellix (vortioxetine)): 14 days (vilazodone); 21 days (vortioxetine). Both act on serotonin. Vortioxetine's gap is longer than most SSRIs. Source: Viibryd label; Trintellix label, section 2.4
SNRIs (Effexor XR (venlafaxine), Pristiq (desvenlafaxine), Fetzima (levomilnacipran), Cymbalta (duloxetine)): At least 7 days (venlafaxine, desvenlafaxine, levomilnacipran); at least 5 days (duloxetine). Raise serotonin and noradrenaline. Shorter label gaps, but the labels still list combining with an MAOI as a contraindication. Source: Effexor XR, Pristiq, Fetzima and Cymbalta labels
Tricyclics (TCAs) (nortriptyline, Anafranil (clomipramine)): At least 14 days. Both labels call combining with an MAOI contraindicated "because of an increased risk of serotonin syndrome". The fatal cases cited by Callaway and Grob involved clomipramine taken in overdose with moclobemide, an MAO-A inhibitor. Source: Nortriptyline and Anafranil labels
MAOI antidepressants (Nardil (phenelzine), Parnate (tranylcypromine), Emsam (selegiline patch)): 14 days between stopping Nardil and starting another MAOI or antidepressant; Parnate's label says MAO inhibition "may persist up to 10 days" after stopping; Emsam: 2 weeks. Stacking a pharmaceutical MAOI on top of ayahuasca's MAO inhibitors and DMT. These labels also require tyramine diet restrictions for 2 weeks after stopping. Source: Nardil, Parnate (section 5.9) and Emsam labels
Bupropion (Wellbutrin SR): At least 14 days. The label's stated concern with MAOIs is "hypertensive reactions" (dangerous blood pressure spikes), not mainly serotonin. Source: Wellbutrin SR label, section 2.4
Mirtazapine (Remeron): At least 14 days. Listed by the label as an increased serotonin syndrome risk with MAOIs. Source: Remeron label, section 2.4
Trazodone (often prescribed at low dose for sleep): At least 14 days. Easy to forget because people take it "just for sleep". It is still an antidepressant with an MAOI contraindication. Source: Trazodone label, section 2.4
Lithium (lithium carbonate): No washout figure found [VERIFY]. The label warns lithium "can precipitate serotonin syndrome" and that risk rises with MAOIs; its half-life is about 18 to 36 hours. Separately, 47% of 62 online reports of lithium combined with classic psychedelics (mostly LSD and psilocybin, not ayahuasca) involved seizures (Nayak et al., 2021). ICEERS lists bipolar disorder as a psychological contraindication for ayahuasca. Source: Lithium Carbonate label, sections 5.6 and 7; Nayak et al. 2021; ICEERS 2019
St John's wort and other serotonergic products (St John's wort; also tramadol, dextromethorphan (cough syrups), triptans, tryptophan): No washout figure found [VERIFY]. The sertraline and lithium labels list St John's wort, tramadol, triptans and tryptophan as serotonergic. A 2026 case report describes severe serotonin syndrome needing intensive care after ayahuasca followed by over-the-counter dextromethorphan (Pack et al., 2026). ICEERS asks you to report all daily medication, "including herbal medicine". Source: Zoloft and Lithium labels; Pack et al. 2026; ICEERS 2019
Where the sources disagree:
The washout starts after your last dose, which means after any taper is finished. A taper itself can take a while. The UK's NICE depression guideline (NG222, 2022) says stopping is "usually necessary" in stages, that people should talk to their prescriber first, and that withdrawal "may take weeks or months to complete successfully". It also warns that stopping abruptly or missing doses can cause withdrawal symptoms, including dizziness, "electric shock sensations", anxiety, low mood and problems sleeping.
So the real timeline is: conversation with your prescriber, then a taper they design, then the washout for your specific drug, then the retreat. If your retreat date is close, the retreat should move, not your medical plan.
There is also a bigger question underneath the numbers: whether coming off your medication is right for you at all. That is a decision for you and your prescriber. Some people stay on their medication and do not sit in ceremony, and that is a legitimate choice.
Every person who wants to sit with us goes through the same three steps before they are accepted:
About 5% of people who do a Clarity Call are declined for a given retreat. Approval typically takes 2 to 10 days.
On medication specifically:
If you are on any of the medications above, tell us on your Clarity Call. Leaving it out does not get you into ceremony faster. It puts you at risk.
Whoever you sit with, these are fair questions, and a serious team will answer them without hesitation:
ICEERS (2019) also suggests looking for centres where participants "go through a preliminary interview and fill a health questionnaire" and where people meeting the centre's exclusion criteria "are not allowed to drink".
No. The harmala alkaloids in ayahuasca block MAO, and SSRIs block serotonin reuptake. Callaway and Grob (1998) warn the combination "may induce a serotonin syndrome with potentially grave outcome", and ICEERS (2019) says taking ayahuasca is not recommended if you are taking antidepressants. Any change to your medication has to be planned with your prescriber.
The US Prozac label says at least 5 weeks after the last dose before starting an MAO inhibitor, because fluoxetine and its metabolite norfluoxetine clear slowly. That gap starts only after your prescriber-guided taper is finished. Whether 5 weeks is enough for ayahuasca in your case is a question for your prescriber and the retreat's medical team.
No. A few days is shorter than the label washout for almost every antidepressant, and stopping suddenly can cause withdrawal symptoms such as dizziness, electric shock sensations, anxiety and low mood (NICE NG222). It can also bring back the symptoms the medication was treating. Never stop on your own. Talk to your prescriber.
Yes. Trazodone is an antidepressant, and its US label says at least 14 days should pass after stopping it before starting an MAO inhibitor. Tell the retreat about it, and talk to your prescriber before changing anything.
Yes. US drug labels for sertraline and lithium list St John's wort as a serotonergic product that raises serotonin syndrome risk. We did not find an official washout figure for it, so ask your doctor, and declare every supplement on your health assessment.
This article is general information, not medical advice. It does not replace a conversation with your own doctor or prescriber. Do not start, stop or change any medication without their guidance.
Reviewed by Elisabet, medical doctor, Taozen team. [DATE TO ADD]
