Error Number 179. Confusing "Librium" with "lithium"

A young man was admitted to a medicaVsurgical unit for treatment of severe depression. The psychiatrist initiated antidepressant therapy with amitriptyline (Elavil).

The next day, after a session with the psychiatrist, the patient became anxious and angry and began breaking furniture in his room. To control the patient's anxiety, the psychiatrist wrote a stat order for Librium (chlordiazepoxide), 100 mg, P.O.

The unit clerk misinterpreted the doctor's handwriting and transcribed the order as lithium, 100 mg, P.O., stat. The medication nurse who checked the order also interpreted the doctor's order as lithium. Then, because the order was stat, she borrowed a lithium tablet (available only in 300-mg strength) from another patient's supply. She divided the tablet into thirds and gave the patient one portion.

Since lithium has no calming effect on this type of behavior, the patient's anxiety didn't subside. The nurse called the psychiatrist to report that the patient's behavior hadn't changed. He immediately gave a stat verbal order for Librium, 50 mg, I.M.-assuming the first dose hadn't achieved the desired effect. When the nurse heard the psychiatrist say Librium, she realized the two drug names had been confused and that an error had been made.

Fortunately, the patient suffered no ill effects from the lithium, and the Librium injection did quell his anxiety.

Several actions (or lack of actions) added up to this medication error. Unquestionably, the psychiatrist's handwriting was not clear. But consider these points:

• The pharmacy was bypassed when the nurse borrowed a tablet from another patient's supply rather than send the order to the pharmacy. As a result, a pharmacist, who probably would have dispensed the correct drug, didn't see the order.
• The nurse didn't know that lithium isn't a stat drug. Since she wasn't familiar with the drug, she should have looked it up. Then she probably would have questioned the choice of drug.
• The nurse had to divide the tablet into thirds to administer the dose ordered. Because one third of a tablet is such an unusual dose, she should have suspected something was amiss.