LME-54

LME-54, or simply LME, also known as lysergic acid methylethylamide or as N-methyl-N-ethyllysergamide, is a serotonergic psychedelic of the lysergamide family related to lysergic acid diethylamide (LSD; LSD-25).^{[2][3][4][5][1]} It is the analogue of LSD in which one of the N-ethyl groups has been replaced with an N-methyl group.^[2][3][4]

Other namesLME54; LME; Lysergic acid methylethylamide; LA-methylethylamide; N-Ethyl-N-methyllysergamide; N-Ethyl-N,6-dimethyl-9,10-didehydroergoline-8β-carboxamide

Routes of
administrationOral^[1]

Drug classSerotonergic psychedelic; Hallucinogen

ATC code

• None

Quick facts Clinical data, Other names ...

LME-54

Clinical data
Other names	LME54; LME; Lysergic acid methylethylamide; LA-methylethylamide; N-Ethyl-N-methyllysergamide; N-Ethyl-N,6-dimethyl-9,10-didehydroergoline-8β-carboxamide
Routes of administration	Oral[1]
Drug class	Serotonergic psychedelic; Hallucinogen
ATC code	None
Identifiers
IUPAC name (6aR,9R)-N-ethyl-N,7-dimethyl-6,6a,8,9-tetrahydro-4H-indolo[4,3-fg]quinoline-9-carboxamide
PubChem CID	164763851
Chemical and physical data
Formula	C19H23N3O
Molar mass	309.413 g·mol−1
3D model (JSmol)	Interactive image
SMILES CCN(C)C(=O)[C@H]1CN([C@@H]2CC3=CNC4=CC=CC(=C34)C2=C1)C
InChI InChI=1S/C19H23N3O/c1-4-21(2)19(23)13-8-15-14-6-5-7-16-18(14)12(10-20-16)9-17(15)22(3)11-13/h5-8,10,13,17,20H,4,9,11H2,1-3H3/t13-,17-/m1/s1 Key:BROWGWCWLHAXPI-CXAGYDPISA-N

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The drug was tested in humans at a dose of 25 μg and was found to produce no effects at this dose in several subjects and to produce weaker effects than a 25 μg dose of LSD in one subject.^[1] Higher doses do not appear to have been assessed.^[1] Based on these findings, LME-54 has been described as weakly active or active but less so than LSD with no specific numbers available.^{[2][3][4][5][6][7]} Its antiserotonergic activity in vitro does not appear to have been reported.^[6]

LME-54 was first described in the scientific literature by Harold Alexander Abramson and Andre Rolo by 1965.^[1][8] It is not a controlled substance in Canada as of 2025.^[9]