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Author(s):  Prince Shelly J

Issue:  Jul/Aug 2004 - Wound Care
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Abstract:  The reader is shown how to perform calculations to solve two problems. The first involves a formulation for morphine sulfate and droperidol injection for patient-controlled analgesia. The reader is shown how to calculate how long the preparation should last if the patient uses the maximum dose, how much droperidol the patient will receive with each 2- to 4-mg dose of morphine sulfate, the percent concentration of morphine sulfate and droperidol in the solution and the final percent w/v strength of lactic acid in the mixture if 0.45 mL of lactic acid solution is used to adjust the pH of the solution. The second problem involves a Duragesic 75-microgram/hour patch that is to be worn and replaced by the patient every 72 hours. The size of the patch is given, and the reader is shown how to calculate the size of the patch in square inches, the quantity of fentanyl remaining in the patch when it is removed, the amount of time it will take for all the fentanyl to be released from the patch, the quantity of drug being released from the patch if the patient runs a specified temperature, the amount of time it will take for all the drug to be released from the patch and the body temperature (given in Centigrade) converted to Fahrenheit.

Related Keywords: Duragesic 75-mcg/hr patch, calculation for, Fentanyl 75-mcg/hr patch, calculation for, Morphine sulfate and droperidol injection, calculation for, Prince, Shelly J., PhD, RPh

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