Labelling this script

[mass]

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Chlorphenamine oral solution 2mg/5ml , 150ml, 2mg to be given four times a day.

I asked the pharmacist why it would be 2mg as it's a liquid. She said that it's one 5ml spoonful each day and I am still confused as to why.

 

[Moxxie]

Chlorphenamine oral solution 2mg/5ml , 150ml, 2mg to be given four times a day.

I asked the pharmacist why it would be 2mg as it's a liquid. She said that it's one 5ml spoonful each day and I am still confused as to why.

There's 2 mg of drug in every 5 mls of liquid- that's what the 2mg/5ml means. In this case, the sig would be "Take 5 mls (one teaspoonful) by mouth 4 times a day." It's much better to write prescriptions this way just in case a drug doesn't come in a particular strength and to make the math easier for dosing.

But say, for example, the drug only came in 5mg/5ml strength, you would have to change the instructions so that the patient got 2 mls 4 times each day - the patient is still getting a 2mg dose at each time period. (And in this case, you'd dispense 60mls instead of 150).

 

[PharmDstudent]

I used to wonder the same thing when I first started working in a pharmacy as a cashier.

There is 2mg of drug dissolved per 5ml of liquid. Even though it's a liquid, the drug itself is measured in mg, not ml.

 

[mass]

is there no w/v calculation to do in order to work out it's 4ml as the doctor wrote 2mg each day.

 

[Pianopooh]

is there no w/v calculation to do in order to work out it's 4ml as the doctor wrote 2mg each day.

You can convert your mg/ml into w/v but I wouldn't recommend it since you'll be giving yourself more work. You should just leave it the way it is.

As for the example you're asking above in reference to Moxxie's 5mg/5ml... if the doctor only wrote the patient needs 2mg of drug given 4 times a day, and 5mg/5ml = 1mg/1ml, you will see the correlation of 1mg to every 1ml. Therefore, the directions for the patient will be 2ml for 4 times a day to receive the proper strength of 2mg per dose each time.

I do not understand what you are asking for when you say "...4ml as the doctor wrote..." please clarify if it's not what I answered in this post! Just remember that most drugs can be given in many different volumes (such as mixing in IV's), but we still call it "X mg" of drug in "Y mL" volume.

 

[RX CARE]

Chlorphenamine oral solution 2mg/5ml , 150ml, 2mg to be given four times a day......... She said that it's one 5ml spoonful each day.

Are u sure??