2C-I

Pre-existing cerebrovascular abnormalities (including Moyamoya disease, arteriovenous malformations, aneurysms) represent an absolute contraindication. The sole peer-reviewed case report documents hemorrhagic stroke in a patient with Moyamoya disease following 2C-I co-ingestion.

Uncontrolled hypertension is an absolute contraindication. Sympathomimetic effects (hypertension, tachycardia, vasoconstriction) are documented in clinical presentations of 2C drug intoxication.

Structural heart disease is a relative contraindication due to sympathomimetic cardiovascular effects documented for the 2C class.

Epilepsy or conditions that lower seizure threshold represent a relative contraindication. Seizures documented in severe 2C drug intoxication (Dean 2013).

Personal or family history of psychotic disorders (schizophrenia, schizoaffective disorder) is an absolute contraindication, based on class-level evidence from serotonergic psychedelics.

Bipolar disorder, particularly bipolar I, is a relative contraindication. Psychedelics can trigger manic episodes in vulnerable individuals.

Pregnancy and breastfeeding are absolute contraindications in the absence of any reproductive safety data.