1Fe-LSD

uncontrolled hypertension, cardiac arrhythmias, significant cardiovascular disease

Uncontrolled hypertension, cardiac arrhythmias, or significant cardiovascular disease. LSD at doses of 100-200 µg produces moderate increases in blood pressure and heart rate (Holze et al. 2021). Individuals with pre-existing cardiovascular conditions face elevated risk.

schizophrenia, schizoaffective disorder, psychosis NOS, family history of psychotic disorders

Personal or family history of psychotic disorders (schizophrenia, schizoaffective disorder, psychosis NOS). 5-HT2A agonism by the liberated LSD moiety can trigger acute psychotic episodes and may accelerate onset in prodromal states. This is the most significant absolute contraindication for the serotonergic psychedelic class.

severe anxiety disorders, current psychological crisis, acute grief, PTSD in acute phase

Individuals with severe anxiety disorders or those currently in psychological crisis face elevated risk of sustained adverse psychological outcomes. LSD-class psychedelics amplify emotional states, and difficult experiences at higher doses can produce lasting distress.

hereditary hemochromatosis, thalassemia major, chronic transfusion therapy, iron overload disorders

Hemochromatosis, thalassemia major, chronic transfusion therapy, or other iron overload conditions. The ferrocene moiety is unique to 1Fe-LSD within the lysergamide class and may release iron upon metabolism. While the absolute iron quantity from a single dose is small, individuals with impaired iron regulation face disproportionate risk. This contraindication is unique to 1Fe-LSD — no other lysergamide analog carries it.

pregnancy

Pregnancy is an absolute contraindication. No reproductive safety data exist for 1Fe-LSD, LSD, or any N1-acyl LSD analog. Ergoline compounds have established uterotonic activity. The ferrocene moiety introduces additional unknown risks to fetal development.

current lithium therapy

Current lithium use is an absolute contraindication. Multiple case reports associate LSD combined with lithium with seizure events. The interaction is considered dangerous across the serotonergic psychedelic class.

current MAOI therapy

Current use of monoamine oxidase inhibitors (phenelzine, tranylcypromine, selegiline, harmine/harmaline). MAOIs can unpredictably intensify and prolong the effects of the LSD moiety liberated from 1Fe-LSD and elevate serotonin toxicity risk.