I wonder what other ambulance services use for doseage? - Will ask at work this week. My Clinical practice guidelines sugest: "Initial dose of 5mg by slow iv injection, (2.5mg for elderly). Followed by aditional 5mg doses every five mins up to 20mg MAX. Medical cases smaller doses seem effective(2.5mg), Trauma cases larger doses may be required, (5-20mg)" and "Morphine, when given IV takes a minimum of 2-3 minutes to begin to work, with peek effect not being achived for 10-20 minuites" - So be carefull out there!