Medication Errors: Where They Happen and Who Is Responsible

The medication process has five steps, each with its own error patterns.

Prescribing. The wrong drug ordered, or the right drug at the wrong dose. Most often this happens at the bedside in busy hospital settings, in the ED, or in primary care when a prescriber is juggling multiple patients and overrides an EHR alert without reading it.

Transcribing. In paper-era practice, illegible handwriting led to drug substitution errors. In EHR-era practice, dropdown-selection errors are common: the prescriber meant hydrOXYzine and selected hydrALAzine. These two drugs have almost identical names and entirely different uses.

Dispensing. Pharmacy errors include wrong drug pulled from the shelf, wrong concentration, wrong package, and labeling errors. Outpatient pharmacy errors get the most attention; inpatient pharmacy errors are common and harder to detect because of the volume of orders processed.

Administering. Nursing errors include wrong patient, wrong dose, wrong route, wrong time, missed dose. Bar-code medication administration (BCMA) systems are designed to catch these, but workarounds are common when systems are slow or when scanning equipment fails.

Monitoring. The dose was right and the administration was right, but the patient's response was not assessed. A patient on heparin develops a falling platelet count that suggests heparin-induced thrombocytopenia; no one notices for days and the patient suffers a serious clot or bleed.

Some drug interactions are predictable and preventable. The major categories: anticoagulants (warfarin, the direct oral anticoagulants) interacting with antibiotics, NSAIDs, or other agents that change bleeding risk; opioids combined with benzodiazepines, which dramatically increases respiratory depression risk; serotonergic agents (SSRIs, MAOIs, tramadol, fentanyl) combined to cause serotonin syndrome; QT-prolonging agents combined to cause torsades de pointes; and renally cleared drugs in patients with declining kidney function.

Prescribers and pharmacists both have a duty to screen for these interactions. Modern EHRs and pharmacy systems flag known interactions automatically, but alert fatigue means many flags are dismissed without being read. When a known interaction causes harm, the question is whether the screen was performed and whether the decision to proceed was reasonable.

The Institute for Safe Medication Practices maintains a list of high-alert medications: drugs with a heightened risk of causing significant harm when used in error. The list includes anticoagulants, insulin, opioids, neuromuscular blocking agents, chemotherapy drugs, and concentrated electrolytes (especially potassium chloride). Hospitals are expected to implement specific safeguards for these medications: independent double-checks, standardized concentrations, restricted access, dose-range checking.

When harm involves a high-alert medication, the litigation question often focuses on whether the institution's required safeguards were followed.

Medication error cases routinely involve multiple defendants because the error process involves multiple actors. A patient who is harmed by a wrong-drug administration in a hospital may have claims against the prescribing physician (for failing to screen for the interaction), the pharmacist (for dispensing without catching the issue), the nurse (for administering without verifying), and the hospital (for system failures in their medication-administration process).

Liability sorting in these cases requires careful chart review and often expert testimony from a pharmacist and a nursing expert in addition to the standard-of-care and causation physicians.

Identify the error precisely: which drug, which dose, which step in the process, and who was responsible. The medication administration record (MAR), pharmacy records, prescriber orders, and BCMA logs all matter. Many of these are captured in the EHR audit trail.

Establish causation: the error caused the injury. This is not always obvious. A patient given the wrong drug may have had a separate underlying condition; the causation expert has to connect the medication error specifically to the harm.

Calculate damages: medical costs of the harm, ongoing care needs, lost income, pain and suffering, and in fatal cases, the wrongful death components recognized in the relevant jurisdiction.