by Michael R. Cohen, R.Ph.
Oral liquid antibiotics tend to have short stability periods. So drug manufacturers often provide their products in powdered form and give pharmacists instructions that specify how the powder should be made into a liquid that can be swallowed. Pharmacists normally mix or “reconstitute” the antibiotic right before it’s dispensed and they place a date on the pharmacy label beyond which the antibiotic begins to lose its potency and should no longer be used.
Unfortunately, the pharmacy reconstitution step sometimes gets missed. Just last week a mother called to let us know about an incident where her pharmacist dispensed her 2 year old daughter’s amoxicillin antibiotic prescription in powder form, which she didn’t notice until she arrived home. She realized her daughter couldn’t take the medicine this way so she took the bottle back to the pharmacy. The pharmacist apologized for overlooking the obvious. He mixed it properly and everything turned out fine thereafter.
But patients may not always realize that they shouldn’t swallow the powder itself or give it to their child. If the prescription label says “Take one teaspoonful three times a day” they might take a teaspoonful of the powder, which is way too much since it’s a concentrated powder. In some cases it could cause harm or at least result in having diarrhea.
In another case a father also was accidentally handed his child’s amoxicillin prescription as powder but the pharmacist also handed him a small cup to measure each dose. Since the directions on the pharmacy label said to give 9 mL (a little less than 2 teaspoonfuls) the child's father filled the cup with enough concentrated powder to reach the 9 mL line and gave it to his child to take with a little water. The child actually got twenty times more medicine than the doctor ordered. The mistake was recognized prior to the next dose when the child complained about the taste. Fortunately, the child was not harmed.
How could a pharmacist forget to add water to powdered medicines anyway? Actually, it's quite easy to make this mistake and it happens from time to time. Pharmacists know it’s best to mix some medicines with water right before it is picked up by the parent or caregiver. That keeps it stable longer. Also, all too often parents see their children’s fever subside and they never pick up the prescription, so an expensive mixed antibiotic is wasted if it’s already been mixed. Sadly, some people simply don’t have enough money to pay for their prescriptions, so perhaps they never pick them up for that reason.
The following conditions suggest there could be an error. You will need to take the medicine back to the pharmacy. Never try to add water to the powder yourself. The amount of water used must be carefully measured to be sure that each teaspoon has the correct amount of medicine in it.
- The medicine is a powder that you were told to take by mouth (swallow), but there are no directions on the label about adding water or another liquid
- The medicine is a powder with directions to measure the dose in teaspoons, tablespoons, or mL (milliliter); these measures are used for liquid medicines
- You expected a liquid medicine and you receive a powdered medicine
- The pharmacy label states the product’s appearance and your medicine doesn’t look like that. For example, “white, opaque liquid.”
Probably the most important and obvious preventive measure is one that is overlooked all too often: Open the bag and bottle to check the medicine before you leave the pharmacy. That will help you spot a mistake right away.
The usual process in most pharmacies is to put a label with the patient's name and directions for taking the medicine on a bottle that contains the correct amount of powder medicine. The medicine is then placed in a bag with a note on it to let the store clerk know that the medicine requires mixing by a pharmacist before it is given to the customer. But sometimes this message can be overlooked, especially if the pharmacy clerk is new and not familiar with the process.
We also tell pharmacists to place new prescriptions for oral liquid medications that need to be reconstituted in a separate shelving area away from other prescriptions. They should mark the area, “Not to be dispensed without speaking to the pharmacist.” This may help remind staff that the product needs to be mixed and that a pharmacist should review directions with the patient or caregiver. They should also be sure to review the label and directions for use with the patient. Effective teaching would likely have stopped these errors.
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