Drug calculation for nurses
Drug calculations Drug calculations appear to be impossibly difficult, unless you break them down into small steps. They are vitally important to get right, yet they are so easy to get wrong. This paper will now look at some commonly used drug calculations and the way that mistakes can happen. Type A calculations When the dose you want is not a whole ampoule. For example: - Prescription states 200mg (milligrams) - You have an ampoule of 500mg (milligrams) in 4ml (millilitres). What volume contains the dose you need? If you have an ampoule of 500mg in 4ml, and you need 200mg, it can appear to be a daunting calculation. The first step is to find out what volume contains 1mg (4/500) and then multiply it by how many mg you want (200). The easy way to remember this is the famous nursing equation: 'What you want, over what you've got, times what it's in' In this instance: 200mg x 4ml / 500mg = 1.6ml The common error here is to get it upside down, and divide what you've go...