Basic Drug Calculations: Problem 3

Ordered: Ampicillin 400 mg IM q6h
Available: Vial with powder.  Label reads: For IM injection, add 3.5 ml diluent (read accompaning circular). Resulting solution contains 250 mg Ampicillin per ml. Use solution within one hour.
How many ml will you administer?

250 mg : 1 ml = 400 mg : x
400 = 250 x
400  ¸ 250  = 1.6 ml

Formula method:

D/H X Q = X

400 mg X 1 ml =  X
250 mg
1.6 ml = X

return