Medication Error Negligence Claims

Types of Medication Error

Medication errors can occur at any stage of the prescribing and dispensing process:

Prescribing errors

• Prescribing a drug to which the patient has a documented allergy
• Prescribing a contraindicated drug given the patient's co-morbidities (for example, an NSAID to a patient with known peptic ulcer disease or renal failure)
• Prescribing a drug that interacts dangerously with existing medication
• Prescribing an incorrect dose — including paediatric dosing errors
• Failure to adjust dose for renal or hepatic impairment
• Prescribing without adequate monitoring (e.g. methotrexate, warfarin, lithium)

Dispensing errors

• A community or hospital pharmacist dispensing the wrong drug
• Dispensing the wrong strength of the correct drug
• Labelling errors leading to incorrect dosing by the patient
• Failure to counsel the patient on how to take the medication or on important interactions or side effects

Administration errors (hospital settings)

• A nurse or clinician administering the wrong drug to the wrong patient
• Administering medication via the wrong route (e.g. intrathecal administration of a drug intended for intravenous use)
• Incorrect rate of administration of intravenous medication
• Failure to check drug charts and allergy status before administration

Monitoring failures

• Failure to monitor therapeutic drug levels (e.g. gentamicin, digoxin)
• Failure to adjust prescribing in response to monitoring results
• Failure to identify drug toxicity from clinical or biochemical features

High-Risk Medications

Certain drug classes are responsible for a disproportionate share of medication error claims due to their narrow therapeutic index or high inherent risk:

Anticoagulants

(warfarin, heparin, low-molecular-weight heparin, direct oral anticoagulants): Dosing errors cause haemorrhage; under-dosing causes thromboembolism.

Methotrexate

Prescribed weekly for rheumatological conditions but carries serious toxicity if taken daily (a recognised and recurring dispensing error). Pulmonary toxicity and bone marrow suppression can be fatal.

Insulin

Dosing errors in diabetic patients cause hypoglycaemia or diabetic ketoacidosis. Concentration errors — 10-fold overdoses — are a recognised never event in hospital settings.

Opioids

Respiratory depression from opioid overdose — including post-operative opioid infusion errors — is a serious and preventable harm in hospital settings.

Gentamicin

A nephrotoxic and ototoxic antibiotic requiring therapeutic drug monitoring. Failure to monitor levels causes irreversible hearing loss and renal failure.

Sodium valproate

In women of childbearing age, prescribing sodium valproate without adequate counselling and pregnancy prevention measures constitutes both a medication error and a consent failure, and may give rise to a claim where a child is born with foetal valproate syndrome.

The Pharmacy Dispensing Error

Community pharmacy dispensing errors are a distinct category of medication negligence. The pharmacist owes an independent duty of care to the patient — separate from the prescribing doctor — and must:

• Dispense the correct drug and dose as prescribed
• Check for obvious prescribing errors
• Identify contraindications and interactions against the patient's medication record (where a patient medication record is held)
• Counsel the patient on new medication

Where a pharmacist dispenses the wrong drug or wrong dose and the patient suffers harm, the dispensing pharmacy (or the pharmacy company as vicariously liable for its employees) is the defendant.

Proving Medication Error Negligence

Medication error claims typically require:

• Expert evidence from a pharmacist or clinical pharmacologist on the standard of prescribing or dispensing
• Expert evidence from a clinician in the relevant specialty on causation — what harm was caused by the error and what would have happened with correct medication
• The prescription, dispensing record, and medication administration record (MAR chart in hospital settings)
• The patient's medication record and allergy documentation

In cases involving dispensing errors, CCTV from the pharmacy premises may be relevant and should be preserved early.

Compensation for Medication Errors

The value of a medication error claim depends on the harm caused. Awards range from modest sums for temporary harm to very substantial awards where permanent injury results — for example, methotrexate toxicity causing pulmonary fibrosis, aminoglycoside toxicity causing permanent hearing loss, or opioid overdose causing acquired brain injury.

Full guide to medical negligence compensation →

Time limits for medication error claims →