Here's a tip courtesy of Shannon DeLuca:
D/H x Q = X
D=Desired (dosage you wish to give)
H=Have (dosage or strength of concentration the med is available in).
Q= Quantity (preparation in which drug is available).
ie: Order is given for 375mg of Ampicillin p.o.
The label on the RX contains 30ml, 250mg/5ml:
375mg (D)/ 250mg (H) x 5ml (Q) = 7.5ml
For IV to Gravity: volume/minutes x drop factor (tubing)= drip rate
For IV to Pump: volume/hour = drip volume
IV fluid tonicity
more to come...