A medication error may or may not result in an adverse drug reaction. Errors in prescribing are common, especially for certain patient populations. Older adults, reproductive-age women, and children are particularly at risk.
Medication errors contribute to morbidity and mortality. Globally, the annual cost associated with medication errors is estimated to be more than 40 billion USD (see World Health Organization: Medication Without Harm). In 2000, the United States Institute of Medicine published a report, To Err is Human: Building a Safer Health System, which revealed that there are more deaths from medication errors than workplace injury (1).
Medication errors may involve:
Wrong choice of a medication or a prescription for the wrong dose, frequency, or duration
Errors in reading the prescription by the pharmacist so that the wrong medication or dose is dispensed
Errors in reading the label of the drug container by the caregiver so that the wrong medication or dose is given
Incorrect instructions to the patient
Incorrect administration by a clinician, caregiver, or patient
Incorrect storage by the pharmacist or patient, altering the medication’s potency
Use of an outdated drug, altering the potency
Inaccurate transmission of prescription information between clinicians
Unclear prescriptions
Digital prescriptions must be entered into the computer ordering system correctly, and handwritten prescriptions must be written as clearly as possible. The names of some drugs are similar and, if not written clearly, cause confusion. In the United States, The Joint Commission provides guidelines for abbreviations used in prescriptions and medical records. For example, “qd” (once a day) may be confused with “qid” (4 times a day). Writing “once daily” is preferred. Electronically transmitted or computer-printed prescriptions can avoid problems with illegible handwriting or inappropriate abbreviations. Electronic prescribing systems that use check boxes or pull-down lists may help direct prescribers to suitable dosages but also may increase the risk of inadvertently selecting the wrong drug or dose.
Inappropriate use of medications
Medications may be given incorrectly, especially in inpatient or long-term care facilities. A medication may be given to the wrong patient, at the wrong time, or by the wrong route. Certain medications must be given slowly when given IV, and some cannot be given simultaneously.
When an error is recognized, it should be reported immediately to a clinician, and a pharmacist should be consulted. Bar codes and computerized pharmacy systems may help decrease the incidence of medication errors.
Improper storage of medications
A pharmacist should store medications in a manner that ensures their potency. Mail-order pharmacies should follow procedures to ensure proper transportation. Storage by patients is often suboptimal (eg, the bathroom medicine cabinet is a common place to store medication, but is not an ideal storage place because of heat and humidity). If stored incorrectly, medications are likely to decrease in potency long before the stated expiration date.
Labeling should clearly state whether a medication needs to be stored in the refrigerator or kept cool, needs to be kept out of excessive heat or sun, or otherwise requires special storage. On the other hand, unnecessary precautions decrease adherence and waste the patient’s time. For example, unopened insulin should be refrigerated, but a bottle in use can be stored safely outside the refrigerator for a relatively long time if not exposed to excessive heat and sun.
Drug expiration date exceeded
Use of outdated drugs is common. Outdated drugs may be ineffective, and some (eg, aspirin, tetracycline) can be harmful if used when outdated.Use of outdated drugs is common. Outdated drugs may be ineffective, and some (eg, aspirin, tetracycline) can be harmful if used when outdated.
Patient error
Medication error often results from a patient’s confusion about how to take medications. Patients may take the wrong medication or dose. Dosing instructions for each medication, including why it has been prescribed, should be completely explained to patients and given in writing when possible. Patients should be asked to repeat back the instructions and should be advised to ask their pharmacist for additional advice about taking their medications. Packaging should be convenient but safe. If children will not have access to the medication and patients may have difficulty opening the container, medications do not need to be provided in childproof containers.
Miscommunication among health care professionals
Another common source of error is inaccurate transmission of prescription information when a patient's care is transferred from one facility or clinician to another (eg, from hospital to rehabilitation facility, from nursing home to hospital, or between a specialist and primary care clinician). Communication between different busy clinicians usually requires active effort, and changes to a medication regimen are common when care is transitioned. Increased attention to communication can help decrease the risk of such errors. Risk has been decreased by various formal drug reconciliation programs, such as preparing a full list of current medications each time a patient transfers from one facility to another.
Reference
1. Institute of Medicine (US) Committee on Quality of Health Care in America, Kohn LT, Corrigan JM, Donaldson MS, eds. To Err is Human: Building a Safer Health System. Washington (DC): National Academies Press (US); 2000.
