TO DOSE OR NOT TO DOSE...

As a young boy I always loved Halloween. Candy? Costumes? What's not to love. I believe that young children enjoy another aspect of Halloween. The anticipation of the unexpected. Who's going to come out from behind the tree and yell "Boo!"

As we become adults we find less enjoyment in the unexpected. Especially as a pharmacist, I wanted to know what is exact, specific, accurate.

With that in mind, I thought it might be helpful to discuss repackaged doses. I believe pharmacists should consider whether they want to deliver the stated volume (dose), or do they want the cup to contain the stated volume (dose)?

For example, when pouring the dose from the unit dose cup (estimated at about 4 seconds), there is a residual amount of drug remaining on the inner surface of the cup. When repackaging, we account for the volume of this residual by re-creating the “administration of the dose” of the specific drug being repackaged. Before we can do that, we must know the specific gravity of the drug. To determine that, our technician will weigh a series of one milliliter samples of the drug, and calculate the grams per milliliter. Knowing that information, we can weigh, or tare, an empty cup, then fill it with the dose required, and deliver a 4 second “pour”; then weigh the cup again to determine the weight in grams of the residual, which can be used to calculate the milliliters of the residual.

This volume, in milliliters, is the amount of drug added to the desired dose volume in milliliters, to arrive at the “to deliver” volume needed. In other words, the amount of drug in a unit dose cup for a 5 milliliter dose may actually be 6 milliliters.

At times, this can be a critical issue, as pharmacists may not consider the residual, and they may order the “to contain” dose in the cup. When this occurs, we contact the pharmacist and review the options. Pharmacists always choose to have the patient get the “delivered” dose. (Of course, this is not an issue if the drug is packaged in an oral syringe, because the entire content is expelled when the plunger is depressed to the fullest, and there is no remaining residual.)

(We find some drugs to be exceptions to the rule, and they are topical oral use medications. Since they are ordered to be administered in a “rinse, swirl, gargle, and spit” form, there is no specific dose needed, only a volume to be contained in the cup.)

Being trained to accurately measure medications, naturally, pharmacists don’t want any surprises. At Shamrock Medical, we agree. Let's save the surprises for Halloween.

Here's to better solutions, 

Dave Bystrom