Medication orders are the most common cause of medical errors�as high as 20% of all mistakes. Errors in physician prescribing, pharmacy dispensing, and nursing administration all contribute to this problem. The following are some common prescribing errors and strategies to help prevent them.

Sound-alike drugs

Many of the 10,000 trade and generic names for currently marketed drugs are almost identical, causing confusion with both written and verbal orders. Examples of sound-alike drugs commonly used in ob-gyn include Celebrex, Celexa, and Cerebrex; Xanax and Zantac; and Cytotec and Cytoxan. Precise spelling, clear handwriting, and having staff read back oral orders are ways to help ensure that your patient receives the drug you intend.

Lack of drug knowledge and incomplete patient history

Physicians should be familiar with the contraindications and interactions of each drug they prescribe and should know all medications a patient is taking, including those prescribed by another physician, over-the-counter drugs, and herbal preparations. A history of drug allergies and illicit drug use should also be obtained. Some drugs are contraindicated or must be used with caution in patients with other comorbid conditions such as renal or hepatic insufficiency, asthma, or chronic obstructive pulmonary disease.

Prescribing the wrong form (oral vs. injectable, regular vs. extended release) or interval can lead to wide discrepancies in bioavailability and therapeutic effect. A useful tool is a hand-held computer with a medication database to check drug interactions and dosing and to keep important patient information readily available.

Dose error calculations

One study found that the most common prescribing errors are dosage errors: both overdoses and underdoses. Calculation errors occur most often in children and the elderly, when body weight, drug metabolism, and excretion must more frequently be taken into account. Dosing calculations for adults may be dependent on actual vs. ideal body weight, or based on a formula that takes both into account, such as the formula used with gentamycin (Ideal Body Weight + 0.4 x Actual Body Weight). Consider obtaining patient drug levels for a certain drug if needed to determine dosage requirements. It can be useful to include clinical pharmacologists on rounds or in busy clinics to assist with drug interactions and dosing, as has been done at some institutions.

The misplaced decimal point

Otherwise known as the misuse of leading and trailing zeros, decimal points incorrectly placed or misread can have tragic consequences. This is especially important when copies of orders, rather than originals, are sent to the pharmacy. Never follow a whole number with a decimal point and a zero (1 mg NOT 1.0 mg), and always use a leading zero for doses less than 1 mg (0.1 mg NOT .1 mg).

Inappropriate use of abbreviations

While they may save a little time, abbreviations are easily misinterpreted by those unfamiliar with a physician's normal practice. Abbreviations should not be used, except when standard, institutionally accepted abbreviations are followed.
� Drug names should not be abbreviated
� There are no safe abbreviations for "once daily": QD is too often mistaken for QID, and OD for "right eye"
� Never abbreviate the word "unit"; a handwritten "U" may look like a zero and cause an overdose error

Illegibility and incomplete orders

Unclear handwriting leads to misinterpreted orders. Printing rather than using cursive handwriting is one way to help clarify orders, along with plain old slowing down and writing legibly. Another solution may be using a computer system to enter orders. After writing a medication order, ask yourself "Can others read this and will they be able to follow it without calling me for a clarification?"

The components of a complete medication order include�clearly written�the name of the drug, dose, route, and frequency of administration and, if prn, the reason for administration. The prescriber's signature and ID or DEA number should also be written.

Written by Karen L. Bruder, MD, FACOG
Member of the Committee on Quality Improvement and Patient Safety
Appeared in the July 2002 issue of ACOG Today.