Help with Dosage Calculation Problem Please! :)

100 ml bottle and TID has nothing to do with the problem.

If the question had something in it like "how many mLs is pt getting a day" TID is valuable. If the question was "how many doses can you get out of the bottle" that is valid to know how big the bottle is.

They are tricky. Thank you very much. So much simpler than it seemed haha.

Problem: "Physician orders 21mg t.i.d. The nurse has a 100mL bottle labeled 6mg/mL. How many mL will the patient receive per dose?"

By using dimensional analysis method I set up my problem to look like this:

the ordered amount of 21mg over 1 & 1 over the sent amount of 6mg...

when i do the problem out i get 3.5mL, which is the CORRECT answer...BUT i am totally leaving out the 100mL bottle aspect and the t.i.d. aspect...

any insight would be amazing!!! :)

You are leaving that information out because you don't need it. The question asks how many mL per dose so how many doses the patient gets in one day doesn't matter. Rarely will you have a question where the total volume of medication available in the bottle is relevant.

Students always get caught by these questions because they haven't quite learned to pick out what's really being asked, and because they almost always have had someone give them a formula that looks like it needs a lot of numbers to fill in.

It's good practice for med administration anyway to slooowww dooowwnn and think about what the question is really asking you. In this case, you know it's 6mg/ml and you want 21mg, and that's all you need to know. That bottle could hold 45cc or 2500cc, and the patient could get it every hour or every week, and the question would still be, "How many ml will the pt get per dose?"