Study drugs
STERILE
On dosing days, DMT fumarate (Cole Parmer Instrument Company Limited, St Neots, Cambridgeshire, United Kingdom; Onyx Scientific, Sunderland, Tyne & Wear, United Kingdom) was reconstituted with saline to give a 5 mg/ml solution and sterile-filtered into sterile vials. To keep infusion rates equal across doses, DMT was drawn into syringes for the bolus and slow-rate infusion, then saline was added to create a total of 5 ml and 15 ml, respectively. The bolus injection and saline flush were administered by a study physician, and the constant-rate infusion was delivered with a BD Alaris GH plus syringe pump (BD Switzerland Sàrl, Eysins, Vaud, Switzerland), with the infusion rate set to 30 ml/h.