Case Study: Wrong Drug Dispensed Despite System Contraindication Alerts Results in Seizure and Hospitalization
Indemnity Payment: $200,000
Legal Expenses: $42,000
Summary
This case involves a 72‑year‑old female patient with a complex medication regimen and significant drug interaction risks.
The patient was a regular customer of a community pharmacy and had been taking phenelzine sulfate, a monoamine oxidase inhibitor (MAOI) used infrequently but associated with numerous severe drug and food interactions. MAOIs require heightened vigilance due to the potential for life‑threatening adverse effects when combined with serotonergic medications.
The patient called the pharmacy to obtain a refill of acyclovir, an antiviral medication she had previously received. The pharmacist indicated that the pharmacy did not have acyclovir in stock and suggested to the patient that a similar medication, valacyclovir, could be substituted. The patient agreed and proceeded to pick up the prescription the following day. The incident occurred when, instead of valacyclovir, the pharmacist dispensed venlafaxine in error, a serotonin‑norepinephrine reuptake inhibitor (SNRI). The venlafaxine prescription dispensed was not an active prescription in the pharmacy’s patient profile.
During processing, the pharmacy’s computer system displayed a high-severity alert regarding a contraindication between venlafaxine and phenelzine due to the risk of serotonin syndrome. All warnings from the pharmacy’s computer system software required a manual override process to proceed with dispensing. Despite these serious alerts, an override was completed and the medication was dispensed to the patient.
Shortly after taking the incorrect medication, the patient experienced seizure activity, prompting a 911 emergency call, transportation to the hospital emergency department for evaluation, and hospital admission. The patient was stabilized with prompt medical treatment, and the incident resulted in no permanent neurologic deficits. Nevertheless, the event caused significant emotional distress for the patient and her spouse.
Resolution
The patient and spouse filed a lawsuit against the pharmacist who prepared/bagged the prescription, another pharmacist involved in the sales transaction when the patient picked up the medication, and the pharmacy entity. The defense acknowledged that a wrong‑drug dispensing error had occurred but noted that the patient’s medical damages were limited due to rapid treatment and resolution of symptoms.
The investigation and discovery revealed that:
- Valacyclovir was not substituted for acyclovir; venlafaxine was dispensed by mistake. Therefore, the “substitution” was not included in the incident report filed by the pharmacy with the state licensing board. Note that therapeutic substitution would not have been allowed in the state at the time of the incident without the prescriber’s approval.
- All pharmacy system warnings required manual overrides regardless of their severity level.
- Pharmacists commonly bypassed all warnings without investigating their significance. All “serious” system warnings required investigation according to internal procedures.
- Pharmacy personnel were trained on handling system warnings, but adherence to training was inconsistent.
- Documentation of retraining following prior similar incidents was inadequate.
- The patient was not provided counseling at pickup, in part because the prescription was treated as a refill.
The pharmacy’s pharmacist‑in‑charge acknowledged that similar warning override incidents had occurred previously, including one event that reached the patient but did not result in harm and another that was intercepted before dispensing.
The matter resolved through settlement, with a total incurred (indemnity plus claim expenses) totaling approximately $242,000. Allegations against certain defendants were resolved separately.
Risk Management Comments
This case highlights a recurring vulnerability in community pharmacy practice: the normalization of overriding medication safety alerts in high‑volume dispensing environments. While alert fatigue is a recognized phenomenon, its presence does not negate the responsibility to investigate warnings that are designed to prevent catastrophic harm.
From a Just Culture and safety culture perspective, it is important to distinguish between human error (unintentional slips or lapses), and at‑risk or reckless behavior, which involves conscious choices to bypass safeguards without appropriate evaluation. This case involved knowingly overriding a high‑severity contraindication alert without investigation or prescriber contact, rather than inadvertent oversight. Under contemporary safety science principles, such conduct would be characterized at minimum as at‑risk behavior, and arguably as reckless behavior, given the well‑established severity of MAOI interactions.
Characterization of this conduct by pharmacy personnel as “human error” impairs organizational learning and prevents implementation of appropriate corrective actions. A Just Culture approach does not focus on blaming honest mistakes but does require accountability when practitioners knowingly assume unjustifiable risk. Organizational factors further increased liability exposure in this case, including inconsistent documentation of training, lack of follow‑up discipline or retraining after prior error events, and workflows that made it easy to routinely override even the most serious warnings.
Regulatory compliance considerations also merit attention. The pharmacist suggested substituting valacyclovir for acyclovir due to inventory availability. At the time of the incident, therapeutic substitution without prescriber authorization was not permitted under applicable state law. Although the substitution was never implemented due to the dispensing error, informal substitution discussions that exceed state regulatory authority may create additional liability exposure and complicate defense of a claim. Clear policies, education on state law compliance, and documentation of prescriber authorization are important safeguards to emphasize.
Risk Management Considerations/Recommendations
Pharmacists and all healthcare professionals are subject to error. For this reason, pharmacies must design systems that anticipate human fallibility while discouraging unsafe behavioral shortcuts. Consider the following recommendations:
1) Differentiate and escalate high‑risk warnings
Not all alerts should be treated equally. Serious contraindication alerts—such as those involving MAOIs—should prompt heightened scrutiny. Depending on the medication and other factors, consider requiring documented review, confirmation of drug interaction and severity, prescriber consultation, and mandatory patient counseling.
2) Reinforce expectations regarding warning overrides
Routine bypassing of serious warnings should not be normalized. Pharmacies should monitor override patterns, identify trends, and intervene when unsafe behaviors become habitual.
3) Leverage patient counseling as a safety barrier
Even when prescriptions are classified as refills, structured counseling can uncover discrepancies. Asking patients whether they recognize the medication and understand its purpose may intercept wrong‑drug errors.
4) Apply Just Culture principles consistently
Organizations should educate staff on the distinctions between human error, at‑risk behavior, and reckless behavior, and align coaching, retraining, or discipline accordingly. Mislabeling unsafe choices as “human error” undermines safety improvement.
5) Learn from prior incidents and near misses
Previous warning‑override events were known but inadequately addressed. Near‑miss and low‑harm events should trigger meaningful system changes before a severe injury occurs.
Sidebar #1
Preventing Wrong‑Drug Errors — Practice Reminder
Claims asserting that the wrong drug was dispensed have remained the top allegation in the CNA/HPSO Pharmacist Professional Liability Claim Report: 3
rd Edition (closed claims from 2017 to 2022). These errors frequently occur in environments characterized by high workload and interruption and may be associated with look‑alike/sound‑alike medication names.
Effective risk mitigation requires more than reliance on final verification. Best practices include:
- Deliberate medication name verification during order entry, product selection, and final check—not solely at pickup
- Incorporate barcode scanning of stock containers and packaged products during the filling process to help ensure that the selected medication and strength match the prescription.
- Provide consistent patient counseling, even for refills, to verify medication recognition and intended use.
- Apply Just Culture principles, recognizing that wrong‑drug errors often result from system design and behavioral drift rather than isolated individual mistakes.
As discussed in the Risk Management Comments and Risk Management Considerations/Recommendations, preventing wrong‑drug errors requires both well‑designed safeguards and clear expectations regarding professional judgment and accountability.
Although the case involved a rarely prescribed medication and a state‑specific regulatory issue, the underlying risk management lessons are widely applicable across pharmacy practice. Wrong‑drug dispensing errors remain a leading source of patient harm and professional liability, particularly in settings where high workload, alert fatigue, and informal workarounds become normalized. Effective prevention depends not on a single checkpoint, but on the deliberate design of safety systems, appropriate use of technology, consistent patient engagement, and clear expectations regarding professional judgment. Applying safety culture and Just Culture principles can help organizations identify and address at‑risk behaviors, strengthen accountability, and reduce the likelihood of patient harm while supporting fair and constructive responses when errors occur.
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Disclaimer.
The information, examples and suggestions presented in this material have been developed from sources believed to be reliable, but they should not be construed as legal or other professional advice. CNA accepts no responsibility for the accuracy or completeness of this material and recommends the consultation with competent legal counsel and/or other professional advisors before applying this material in any particular factual situations. This material is for illustrative purposes and is not intended to constitute a contract. Please remember that only the relevant insurance policy can provide the actual terms, coverages, amounts, conditions and exclusions for an insured. All products and services may not be available in all states and may be subject to change without notice. Certain coverages may be provided by a surplus lines insurer. Surplus lines insurers do not generally participate in state guaranty funds, and insureds are therefore not protected by such funds. The claims examples are hypothetical situations based on actual matters. Settlement amounts are approximations. Certain facts and identifying characteristics were changed to protect confidentiality and privacy. “CNA” is a registered trademark of CNA Financial Corporation. Certain CNA Financial Corporation subsidiaries use the “CNA” trademark in connection with insurance underwriting and claims activities. This material is not for further distribution without the express consent of CNA. Copyright © 2026 CNA. All rights reserved. Published 05/2026.