LSD

Category: alkaloid

Aliases: Lysergic acid diethylamide, LSD-25

Pharmacological Mechanism

Ergoline lysergamide derived from ergot alkaloids (Hofmann 1938). Very potent 5-HT2A agonist (Ki ~3.5 nM) plus partial activity at 5-HT1A/1B/2C, D2, adrenergic. Unique binding kinetics — extended receptor-bound residence time gives the long clinical duration. Metabolised by CYP2D6 + CYP3A4 to inactive metabolites.

Half-Life (t½)

PO: 3.6h

Dosing Guidelines

• PO: Typical 100 mcg (Range: 50–200 mcg)
• SL: Typical 100 mcg (Range: 50–200 mcg)

Target Organ Systems

• nervous
• digestive

Interactions

• Psilocybin (caution): Complete 5-HT2A cross-tolerance develops over 2–3 days of repeat dosing; do not alternate.

Pathways It Modulates

• 5-HT2A psychedelic signaling (activator) — 5-HT2A + 5-HT1A + D2 partial
• BDNF / TrkB neurotrophic signaling (activator) — TrkB direct + 5-HT2A (psychoplastogen)
• Metabotropic glutamate receptors (activator) — 5-HT2A → cortical glutamate
• Serotonin receptor pharmacology (activator) — 5-HT2A (partial agonist) + 5-HT1A/2C

Chemical Identifiers

• PubChem CID: 5761
• Formula: C20H25N3O
• Molecular weight: 323.43 g/mol
• InChIKey: VAYOSLLFUXYJDT-RDTXWAMCSA-N
• SMILES: CCN(CC)C(=O)[C@H]1CN([C@@H]2CC3=CNC4=CC=CC(=C34)C2=C1)C

References

• PMID 26108222