GlossaryCYP enzyme (CYP2D6 / CYP1A2)

CYP enzyme (CYP2D6 / CYP1A2)

Cytochrome P450 enzymes responsible for metabolising psilocin and many psychiatric medications in the liver. CYP2D6 is strongly inhibited by fluoxetine (Prozac) and paroxetine (Paxil), slowing their own clearance and potentially affecting psilocybin metabolism. CYP1A2 is strongly inhibited by fluvoxamine (Luvox), which may unpredictably increase psilocin blood levels — making that combination pharmacokinetically risky. Relevant when combining psilocybin with any psychiatric medication.

Full Explanation

CYP enzymes (CYP2D6 and CYP1A2) are cytochrome P450 enzymes responsible for metabolising psilocin and many psychiatric medications in the liver. CYP2D6 is strongly inhibited by fluoxetine (Prozac) and paroxetine (Paxil), slowing their own clearance and potentially affecting psilocybin metabolism. CYP1A2 is strongly inhibited by fluvoxamine (Luvox), which may unpredictably increase psilocin blood levels — making that combination pharmacokinetically risky. Relevant when combining psilocybin with any psychiatric medication.

See: Microdosing on SSRIs (/guides/microdosing-on-ssris).

Why It Matters

Understanding CYP enzymes is essential for anyone considering psilocybin while on SSRIs or other psychiatric medications — interactions can alter both drug levels and trip intensity.