"the only times i have had the medicine is when i have had arterial surgeries and dilaudid was administered by iv. as previous posts have stated, it goes into effect 30 - 60 seconds after administration, but with a slight heating effect in the injected vein. soon after the blissful pain relief has occurred. i was able to intently listen to a book or watch tv: sleep was also easy if i wanted. this was only a 1mg dose, but surprisingly effective. it killed the pain while allowing one to be mentally alert (if desired), unlike morphine. i highly recommend this medicine for hospital pain relief, but for longer term pain relief, up to 6 hours, it was supplemented with 5 mg of vicodin."