Brief cardiovascular and sensory symptoms

intensity 

+ PLUS ONE — Clearly noticeable. You can tell when it began and how it's changing, though its full character isn't apparent yet.

intensity 

− MINUS — No noticeable effect.

Intravenous administration produced mainly physical effects: slowed heart rate, low blood pressure, eye-focusing difficulty, tingling, cold hands and feet, and light-headedness. Nearly all symptoms cleared within about forty-five minutes, though a few subjects had lingering slow heart rate or drowsiness.