Pharmacy Math Question 
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Comments (2) 
Lorian43 in Apex, North Carolina 61 months ago 
Heather, What you want to do first is calculate what your original strength is per ml.
The formula for this problem is final volume over initial volume = initial strength over final strength. Final volume is what you are solving for or (x)ml = 4mg is initial strength
Or (x)ml over 100ml = 4mg over 2mg; Then you cross multiply. So that you would have 2mg times (x) = 100mg times 4mg or 2(x) = 400. Since you are solving for (x) you would divide 400 by 2 and you get 200ml. You already have 100ml so you would just need to add another 100ml of cherry syrup to your original 100ml to equal a concentration of 2mg/ml. Hope that helps 
amy mal in Long Beach, California 40 months ago 
The recommended dose of phenytoin sodium is 6 mg / kg / d administered in three equally divided doses. The phenytoin stock suspension is available in a 12 5 mg / 5 mL concentration. How much should be given to 44 lb. child for each dose? 
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