Safety pharmacology of acute mescaline administration in healthy participants.

Mescaline doses up to 800 mg appear safe in controlled clinical settings for healthy individuals. In two double-blind, placebo-controlled studies with 48 participants and 96 administrations, positive subjective effects increased with dose and consistently outweighed negative effects. Autonomic effects rose moderately: systolic blood pressure exceeded 180 mmHg in 6% of administrations, heart rate above 100 beats/min occurred in 3%, and body temperature above 38 °C in 5%. Nausea limited higher doses. Kidney and liver function and blood cell counts remained normal. Flashbacks followed 2% of administrations. Adverse effects totaled 51 at 100 mg and 180 at 800 mg.

Study at a glance

Abstract

Psychedelics, including mescaline, may serve as novel treatments for depression and anxiety. However, data is scarce on the safety of mescaline. The present pooled analysis included two double-blind, randomized, placebo-controlled studies with a total of 48 participants and 96 mescaline administrations. Single oral-dose administrations (n = 16/dose) of mescaline at doses of 100-800 mg were used. Acute subjective and autonomic effects and acute and subacute adverse effects were recorded. Liver and kidney function, blood cell counts, and "flashbacks" were documented at the end of the studies. Positive subjective effects dose-dependently increased and were higher than negative subjective effects for all mescaline doses. Autonomic effects increased moderately. Systolic blood pressure remained 100 mmHg was measured in 6%, heart rate > 100 beats/min was measured in 3% and body temperature > 38 °C was measured in 5%. The total number of acute adverse effects was 51, 12, 179, 143, 165 and 180 at 100, 200, 300, 400, 500 and 800 mg doses of mescaline, respectively. Nausea was dose-limiting. Kidney and liver function and blood cell counts remained normal. "Flashbacks" were reported after 2% of all mescaline administrations. These findings suggest that the administration of single mescaline doses up to 800 mg are safe in a controlled clinical setting with regard to acute psychological and physical harm in healthy participants.