Wrong Drug / Wrong Strength Errors: The Most Common Dispensing Error, The Legal Aftermath and How to Report It Correctly.

Wrong Drug / Wrong Strength Errors: The Most Common Dispensing Error, The Legal Aftermath and How to Report It Correctly.

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Wrong-drug and wrong-strength mix-ups are the most common dispensing errors in both community and hospital pharmacies. They happen because many products look and sound alike, strengths vary widely, and busy workflows create room for confirmation bias and missed checks. This article explains what these errors are, why they occur so often, what to do immediately, the likely legal aftermath, and how to report them correctly so you protect patients, yourself, and your organization while improving the system.

What counts as a “wrong drug” or “wrong strength”?

Wrong drug means the patient receives a different active ingredient than prescribed. For example, hydroxyzine is dispensed instead of hydralazine, or cephalexin instead of amoxicillin. The root problem is frequently look‑alike/sound‑alike names, similar packaging, or nearby shelf placement.

Wrong strength means the correct drug is supplied, but the potency is incorrect. Common examples include levothyroxine 125 mcg instead of 50 mcg, or metoprolol tartrate 100 mg instead of 25 mg. This often stems from unit confusion, decimal misinterpretation, or a picker pulling a familiar strength without checking the label.

Why this matters: Wrong-drug errors create unpredictable effects (no benefit from the intended therapy and possible harm from the unintended one). Wrong-strength errors can cause underdosing (treatment failure) or overdosing (toxicity). Both can lead to emergency visits, hospitalizations, and long-term consequences, especially with high-alert medications (anticoagulants, insulins, opioids, antiarrhythmics).

Why these errors happen more than others

They are common because the system makes them easy to make and hard to catch. Specific drivers include:

  • Look‑alike/sound‑alike (LASA) names and packaging. Similar names (e.g., hydralazine/hydroxyzine) and similar bottles or blister packs invite selection errors. Shelving them near each other multiplies the risk.
  • Strength proliferation. Drugs with many strengths (levothyroxine, opioids) increase the chance of pulling the wrong one, especially when bottles share the same color scheme.
  • Technology mismatch. E‑prescribing systems may default to a different strength or NDC than the pharmacy stocks. Dropdown menus group similar items together, priming pick errors. Barcoding helps, but workarounds (scanning from a shelf tag or outer case) defeat the control.
  • Confirmation bias. When the product “looks right,” the brain stops searching for disconfirming details (strength, dosage form). Interruptions amplify this bias.
  • Decimal and unit confusion. A missing zero (0.5 vs 5 mg), microgram vs milligram, or U‑100 vs U‑200 insulin can lead to 10x dosing mistakes.
  • Inventory and labeling quirks. Mixed stock in the wrong bin or outdated NDC images in software increases selection errors.
  • Rushed verification. High volume, staffing shortages, and multitasking reduce the time for independent checks, patient counseling, and imprint verification.

Immediate steps when the error is discovered

Act quickly. The goal is to limit harm, be transparent, and fix the system to prevent a repeat.

  • Stop the medication. If the patient still has the wrong product, instruct them to hold it immediately. If they have taken it, assess timing and dose.
  • Assess the patient. Ask about symptoms, comorbidities, and concomitant drugs. Determine risk based on the specific wrong drug or strength and the duration of exposure.
  • Notify the prescriber promptly. Agree on a clinical plan: monitoring labs (e.g., INR after wrong warfarin dose), antidotes, bridging therapy if doses were missed, or observation at home vs referral to urgent care/ED.
  • Provide the correct medication quickly. Arrange immediate replacement or delivery. Clarify exactly how and when to restart or adjust doses.
  • Disclose and apologize. Explain what happened in plain language, the potential effects, and what you are doing now. Avoid speculation or blame. Many jurisdictions protect expressions of sympathy; focus on facts and care plans.
  • Document objectively. Record times, products (NDC, lot), labels, counseling provided, and patient contacts. Save the wrong product for investigation if safe to do so.
  • Monitor and follow up. Schedule follow-up calls or visits to check on symptoms, adherence, and lab results as needed.
  • Trigger an internal safety report. Start root cause analysis before memories fade.

For patients: If you suspect a wrong drug or strength, stop taking it, keep the bottle, and call the pharmacy. If you have symptoms (e.g., dizziness, bleeding, severe drowsiness, shortness of breath), seek emergency care and bring all medications.

Legal aftermath: what typically follows

Most cases resolve through internal remediation and patient support, but understanding the legal landscape helps you respond wisely.

  • Standard of care and negligence. A plaintiff must show the pharmacist or pharmacy breached the standard of care, causing harm and damages. Dispensing the wrong drug or strength is usually a breach; the dispute often centers on whether it caused the injury and the extent of damages.
  • Vicarious and corporate liability. Employers are typically liable for employees’ actions within the scope of work; corporate policies and staffing levels may be scrutinized.
  • Regulatory action. State boards can investigate, issue fines, mandate retraining, or restrict licenses. Recurrent or serious harm (“sentinel events”) triggers more scrutiny.
  • Criminal exposure is rare. It is generally limited to reckless or intentional conduct causing severe harm. Routine errors without gross negligence seldom lead to criminal charges.
  • Documentation matters. Clear, factual, contemporaneous notes support patient care and demonstrate diligence. Avoid editorializing or blaming; stick to what, when, who, and objective findings.
  • Disclosure and apology. Early, honest communication builds trust and can reduce litigation. Many states have “apology laws” that limit the use of expressions of sympathy in court. Know your local rules; involve risk management.
  • Insurance and counsel. Notify your employer and malpractice carrier promptly. They can coordinate patient support, legal guidance, and reporting.

How to report it correctly (and safely)

Report for two reasons: to meet obligations and to learn from the event. Good reporting captures facts, protects patient privacy, and routes information to the right places.

  1. Internal reporting (always).
    • Enter an event in your organization’s safety system as soon as possible.
    • Include: patient initials/ID, dates/times, prescribed vs dispensed drug/strength/NDC/lot, how the error was detected, who was notified, patient status, and immediate corrective actions.
    • Attach artifacts: label images, shelf photos, e‑Rx screen captures. These help root cause analysis.
    • Flag if high‑alert drugs, pediatric doses, or anticoagulants are involved.
  2. Mandatory external reporting (when applicable).
    • State board of pharmacy: Some jurisdictions require reporting of serious harm or death; check your state’s thresholds and timelines.
    • The Joint Commission (hospitals): Sentinel events may require review and reporting; initiate a root cause analysis within the required timeframe.
    • Employer or chain-level escalation: Corporate policies may mandate immediate notification of risk management.
  3. Voluntary learning systems (strongly encouraged).
    • ISMP National Medication Errors Reporting Program: Share anonymized details to help others learn. These reports surface system vulnerabilities and drive national safety alerts.
    • FDA MedWatch: Use when the error causes an adverse event or reveals confusing labeling/packaging. This helps regulators and manufacturers improve products and instructions.
    • Manufacturer quality complaints: Report look‑alike packaging or misleading labels; companies can redesign or issue field alerts.
  4. Protect confidentiality appropriately.
    • De‑identify patient data except where required by law.
    • Avoid blame language; describe system factors and observable facts.
    • Use Patient Safety Organization (PSO) channels if available to access privilege protections for analysis.

Documenting the event: what good documentation looks like

Good documentation explains what happened and enables learning without guessing motives.

  • Just the facts: “Prescribed hydralazine 25 mg; dispensed hydroxyzine 25 mg. 12 tablets taken over 4 days. Patient reported daytime sedation; no falls.”
  • Traceability: Lot numbers, NDCs, and images of stock bottles and labels.
  • Timeline: Order entry, filling, verification, pickup, detection, contacts, and follow-up times.
  • Clinical response: Notifications, monitoring plan, counseling provided, replacement issued.
  • System factors: Shelf adjacency, label fonts, bin mix-ups, alert fatigue, interruptions, scanner availability, workload at the time.
  • Actions to prevent recurrence: Storage separation, barcode hard stops, Tall Man lettering, staff training, software fixes.

Prevention that actually works

Focus on barriers that do not rely on memory or vigilance alone.

  • Barcode verification at pick and final check. Aim for near‑universal scanning. Eliminate workarounds by auditing and fixing scanner placement, label quality, and system timeouts.
  • Physical separation and Tall Man lettering. Keep LASA drugs apart; use shelf tags with Tall Man (e.g., hydrOXYzine vs hydrALAzine). Place high‑alert drugs in distinct bins with warnings.
  • Imprint and “show‑and‑tell” at counseling. Open the bottle with the patient, compare tablet imprint and appearance to the image on the label, and restate the strength and indication. This step catches many errors before harm.
  • Standardize and simplify. Limit stocked strengths where clinically appropriate. Default to the most commonly prescribed NDCs to reduce variation.
  • High‑alert double checks. Independent verification for anticoagulants, insulins, opioids, pediatric liquid concentrations, and chemotherapy.
  • Dosing guardrails. Use software checks for weight‑based and maximum daily doses; build hard stops for extreme doses or dangerous combinations.
  • Manage interruptions. Use checklists, “do not disturb” zones for final verification, and batching to reduce task switching.
  • Clean inventory and bins. Remove discontinued NDCs, fix mis-binned stock, and avoid mixed strengths in the same bin.
  • Continuous learning. Share near misses internally; what nearly happened is often the best predictor of what will happen.

Quick reference checklists

If you discover a wrong-drug/strength error (pharmacy team):

  • Call patient; stop the medication; assess symptoms.
  • Notify prescriber; agree on monitoring/treatment plan.
  • Provide correct medication and clear instructions.
  • Disclose facts; apologize; offer follow-up support.
  • Document objectively; save artifacts; report internally.
  • Evaluate system factors; implement immediate fixes.
  • Report externally as required; consider ISMP/FDA reporting.

If you are the patient:

  • Stop taking the suspect medication; keep the bottle.
  • Call the pharmacy and your prescriber; describe symptoms.
  • Seek urgent care for severe symptoms (e.g., bleeding, fainting, trouble breathing).
  • Bring all medications to any visit.
  • Ask for the corrected prescription and a clear plan.

Wrong-drug and wrong-strength errors are common because everyday systems make them easy. The fix is not heroics; it is clearer labels, better separation, reliable scanning, open counseling, and a culture that reports and learns. When an error occurs, quick clinical action, honest disclosure, precise documentation, and thoughtful reporting protect patients and strengthen the safety net for everyone.

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