At least two Phase 3 psychedelic trials will formally adopt standardized fluoxetine washout protocols (documented in trial registry or protocol amendment) by Q4 2026.

Researchers running big psilocybin studies will update their rules to require people taking fluoxetine (Prozac) to stop the drug before the trial, and they'll document this in public trial databases. This matters because fluoxetine might interfere with psilocybin's effects, and trials need to show clean results.

The fluoxetine-behavior interaction finding creates proactive protocol amendment incentive at MAPS-affiliated and FDA-scrutinized sites. However, 'formally adopt' requires verifiable protocol amendment or registry update, not just internal policy. The base rate for mid-trial protocol amendments at this specificity within 8 months is moderate. Confidence adjusted downward from original; the mechanism is plausible but the specific threshold of two trials with formal documentation is demanding.