Avoiding Prescription Errors

The important topic of patient safety was initially brought to light in 1999 by the Institute of Medicine with the publication of To Err is Human: Building a Safer Healthcare System (available online at https://www.nap.edu/read/9728/chapter/1). These landmark reports quickly brought patient safety to the forefront of medicine, attributing at least 44,000 deaths per year to medical errors, more than deaths due to motor vehicle accidents (43,458) or breast cancer (42,297) (Kohn, et al., 2000).

To Err is Human defines an adverse event as an injury resulting from a medical intervention, not due to the underlying condition of the patient. It defines preventable adverse events as an adverse event that is due to an error. Perhaps someone forgot to wash their hands or gave the wrong dose of a medication. This is in opposition to an adverse event that is not preventable, or not due to an error. Perhaps nothing could have prevented the poor outcome. Everything was done correctly, the patient was simply too sick to have a good outcome.

Although many of these definitions are commonplace now, To Err is Human was the first report to highlight and define many important terms in safety for drug prescription and administration. An adverse drug event (ADE) is any error at any step along the pathway that begins when a Nurse Practitioner or other provider prescribes a medication and ends when the patient actually receives the medication. The medication does not necessarily have to cause harm the patient to be considered harmful. The fact that the patient received unintended medication, or medication that did not follow the "5 Rights" is enough to consider it having caused harm. From nursing school, remember that the five rights of medication safety are administering the Right Medication, in the Right Dose, at the Right Time, by the Right Route, to the Right Patient.

A potential ADE is one that is stopped before it actually makes it to the patient because someone noticed and intervened before the process was completed. About half of ADEs are preventable.

Please note that you may also hear the term Adverse Drug Event as a term for an allergic reaction, which we have discussed previously (see section on Adverse Drug Reactions). You would have to understand the context in which the term was used to understand the meaning. In this section we are only discussing errors, not allergies.

Polypharmacy is the biggest risk factor for ADEs. The more medications a person takes, the more opportunity there is for medication interactions, and for the person to not administer the medication correctly. A drug that needs to be given at multiple times a day is more likely to be forgotten, missed, or given at an incorrect time. A drug that has specific instructions, such as with or without food, is likely to be given incorrectly if there are other drugs with conflicting schedules.


Being old or young is another risk factor for ADEs. As has already been discussed, extremes of age will change a person’s pharmacokinetics. Many drugs require changes in dosing due to either infancy or renal insufficiency, which can cause complications and errors.

The ability to read and write will improve a person’s ability to understand instructions. A person who cannot read or write will tend to ask fewer questions, even if they did not understand the instructions in the first place. Reduced health literacy will significantly increase the risk for ADEs.

So, why is error reduction important, anyway? Well, Nurse Practitioners have almost 10,000 drugs available with which to treat patients, and nearly one third of adults in the U.S. take more than five drugs. It is estimated that 2-5% of hospital admissions in the United States experience a drug-related error, which makes it one of the most common types of errors.

However, there are many things that you can do to prevent errors in your own practice.

First, use two patient identifiers. This seems obvious now, but there was a long time that we were not doing this. Be sure to use something like date of birth (DOB) in addition to name.

Always verify allergies and patient reactions. Again, seems straightforward, right? Unfortunately, it is often a neglected step and is a major source of errors. It is also not as easy as it sounds. Sometimes patients misunderstand a known drug side effect as an allergy, so talking about these misperceptions can be important.

Highlight critical diagnoses that impact prescribing, such as diabetes, kidney disease, and liver disease. You can usually do this on a problem list, or in an alert section of the patient’s electronic medical record. Leaving clues like these will help cue you in the future and will help a covering provider if you are taking vacation or a sick day.

Review patient medications at each and every visit to reduce medications if possible. Basic medication reconciliation is the process of identifying the most accurate list of drugs that the patient is taking, including name, dosage, frequency, and route, by comparing the medical record to an external list of medications obtained from a patient, hospital, or other provider. You or someone in your office must do this at every single visit. You can go one step further, and offer much better patient care, by considering if your patient really needs to be on each of the drugs. Many times a patient was started on a drug many years ago for a short term problem, but then the drug was never discontinued.

Another way to reduce unnecessary drugs is to prescribe drugs with dual purposes if possible. Many drugs have more than one indication.

Give printed patient education if available, and always give a printed medication list at the end of every visit. Even if the person themselves is unable to read or write, they will often have a support person who will be able to assist at home.

Encourage your patients to use a single pharmacy so that one facility has all of the information on all of the drugs that they are taking. Sometimes the patients forget that they have visited a specialist or will forget that the specialist has added or changed a drug. If they always go to the same pharmacy, however, you have a double check.

Avoid the use of sample medications as this bypasses the double-check of the pharmacy. If your patient is seeing a specialist he or she may have a new medication or a new allergy that they forgot to report to you that the pharmacist would otherwise be aware of. The pharmacist is a great teammate for error prevention.

Nurse Practice Acts

The prescriptive authority of Nurse Practitioners is based on each state’s Nurse Practice Acts. Each state has a Nurse Practice Act that establishes a Board of Nursing, which in turn establishes the specific rules for prescriptive authority for Nurse Practitioners for that state.

Nurse Practice Acts are set up to protect the public and set the standards for many aspects of nursing practice, including mandatory education and scope of practice. Nurse Practice Acts are an important step in error reduction.


In this article, we have discussed the very basics of pharmacology. This is the foundation on which all other pharmacology activities build. We discussed the basic definition of a drug, the activities of a drug, and we classified drugs. We discussed drug receptors on cells and explored how people may have differences that would influence drug selection. We looked at the future through pharmacogenomics and discussed the vital importance of safety.

Prescribing in today's world as a nurse practitioner is a daunting task, but it is absolutely vital to the role. Our patients count on us to guide them through this very complex world of drug choices. With this information we are up to the task.

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