Use Extreme Caution with Morphine Sulfate Oral Solutions

Author: Kate Kelly, PharmD, and Allen J. Vaida, PharmD, FASHP

Problem

A community pharmacist received a faxed prescription for a 94-year-old nursing home resident for morphine sulfate concentrate oral solution 20 mg/mL. The directions stated to use "5 mg sl q 4 hours prn pain and restlessness." After the pharmacist entered Roxanol (morphine sulfate 20 mg/mL concentrated oral solution) into the drug selection screen of the computer, he was prompted to choose an available generic equivalent from the drug list. From the list, he mistakenly chose morphine sulfate solution 20 mg/5 mL to process the prescription. Somehow the pharmacy had linked this product as a generic equivalent to Roxanol, even though it had a different concentration. He then proceeded to obtain the highly concentrated 20 mg/mL formulation from the shelf. The computer-generated label affixed to the product, however, indicated "morphine sulfate 20 mg/5 mL," with the directions he had entered for the highly concentrated formulation: "Take 5 mg (0.25 mL) as a sublingual dose every 4 hours as needed for pain and restlessness."

The medication and calibrated dropper were finally sent to the nursing home some 12 hours after the initial order was faxed in to the pharmacy. Before administering the medication, the nurse noted that the volume to be administered on the directions did not match the strength on the label. Yet, possibly feeling pressured to administer the medication because of the significant time delay, she proceeded, without a double check, to administer 1.25 mL (which she believed to be 5 mg, based on the pharmacy's label concentration of 20 mg/5 mL, but which was actually 25 mg). She administered a second dose 4 hours later. The patient died after receiving the second dose. In this case, the error began with a computer linkage problem and proceeded due to lack of double checks in the drug-dispensing and-administration process.

In a second report, a physician intended for a patient to receive morphine sulfate solution 20 mg/5 mL and to take 1 mL (4 mg) every 2 hours as needed. The prescription was incorrectly written, however, as "Roxanol 20 mg/5 mL" with the instructions "1 mL q 2 h prn." Noticing only the familiar drug name, both the technician and the pharmacist overlooked the concentration and proceeded to dispense Roxanol (20 mg/mL). The patient died after receiving the 1 mL (20 mg) dose 8 times.

In still another report, a patient in a long-term care facility received 10 mL (200 mg) of Roxanol (20 mg/mL) instead of the prescribed amount, 10 mg (0.5 mL). The patient experienced periodic hypotension and dizziness but recovered. The error was discovered during a narcotic shift count.

Safe Practice Recommendations

To reduce the number of errors with morphine oral solutions, consider the following:

? Less concentrated morphine sulfate solutions (10 mg/5 mL or 20 mg/5 mL) should be used when the dose is relatively low. The highly concentrated solution (20 mg/mL) should be reserved for patients who require sublingual doses or higher-than-usual doses due to severe chronic pain.

? Build alerts into computer orderentry systems to warn about mixups between various morphine concentrations.

? Because all morphine solutions are likely to be stored together, consider storing the highly concentrated solution in a separate area. Add auxiliary labels to call attention to the different concentrations.

? Stock only the smaller bottles (30 mL) of the highly concentrated solution.

? Never cover the concentration listed on the manufacturer's label with a pharmacy label.

? Pharmacy label directions should include the dose in both metric weight (milligrams) and volume (milliliters).

? Provide a measuring device that is capable of accurately measuring the specified dose. Show patients how to measure the dose, and then have them perform a return demonstration.

? With the exception of community pharmacies, a highly concentrated solution should not be stored as a stock item.

? When morphine solution is dispensed, have 2 individuals independently double check the prescription (compare the original prescription with both the product to be dispensed and the computer-generated label) before it reaches the patient.

? Pharmacists should counsel all patients (or their caregivers) about oral morphine before they leave the pharmacy. Ask patients what the prescriber has told them regarding the dose and how to take the medication. Inform patients of the potential for error when prescribing and dispensing these medications.

? Share the above errors with staff members to heighten their awareness of the confusion between the various morphine solutions.