Chapter 4. Medication Errors

In June 1995, a middle-aged man named Ramon Vasquez went to see his physician in Odessa, Texas, to investigate his chest pain. His physician, suspecting angina, prescribed a medication. The actual prescription is reproduced in Figure 4-1.

Here's a quiz. Do you think the highlighted portion of the prescription is for:

1. Plendil, a calcium channel blocker sometimes used to treat angina?

2. Isordil, a long-acting nitrate also used to treat angina?

3. Zestril, an angiotensin-converting enzyme inhibitor used to treat high blood pressure and heart failure?

So what did you think? I once asked an audience of hospitalists to interpret this prescription. Half said it was Plendil, one-third Isordil, and the rest Zestril.

The physician actually intended to prescribe 120 tablets of Isordil, at its typical dose of 20 mg by mouth (po) every (Q) 6 hours. Ramon Vasquez's pharmacist read the prescription as Plendil, and instructed the patient to take a 20-mg pill every 6 hours. Unfortunately, the usual starting dose of Plendil is 10 mg/day, making this an eightfold overdose. A day later, Mr. Vasquez was critically ill from low blood pressure and heart failure. He died within the week.

The modern pharmaceutical armamentarium represents one of healthcare's great advances. There are now highly effective agents to treat most common maladies: high blood pressure and cholesterol, diabetes, heart disease, cancer, stroke, acquired immunodeficiency syndrome (AIDS), and more. Taken correctly, the benefits of these medications far outweigh their side effects, though the latter remains a concern even when medications are prescribed and taken correctly.

But the growth in medications (there are now more than 10,000 prescription drugs and biologicals—and 300,000 over-the-counter products—available in the United States1) has led to a huge increase in the complexity of the medication prescribing and administration process. It has been estimated that at least 5% of hospital patients experience an adverse drug event (ADE; harm experienced by a patient as a result of a medication, from either a side effect or the consequence of an error) at some point during hospitalization. Another 5–10% experience a potential ADE, meaning that they nearly took the wrong medicine or the wrong dose but didn't, often thanks to a last minute catch or dumb luck.2 When patients are on high-risk medications such as warfarin, insulin, and heparin, errors are particularly common: in a national sample of hospitalized Medicare patients, one in seven receiving heparin experienced an ADE.3 The cost of preventable medication errors in U.S. hospitals has been estimated at $16.4 billion annually.4

Things are no safer outside the hospital. Nearly 1 in 20 hospital admissions can be traced to problems with medications, many of them preventable.5 When a large group of outpatients on ...