Prendergast v Sam & Dee – Case Summary

Prendergast v Sam & Dee

Court of Appeal

Citations: (1989) 1 Med LR 36.


D1 was a pharmacy company. D2 was D1’s director. He was also employed to work as a pharmacist at D1’s pharmacy. In 1983, D3, a doctor, wrote out a prescription for the claimant for three different drugs to treat his asthma. However, due to the doctor’s poor handwriting, D2 misread the prescription and gave the claimant the wrong drugs.

One of the drugs the claimant was accidentally given was a diabetes drug which reduces blood sugar. As a result of taking this drug, the claimant had a hypoglycaemic episode which caused brain damage. The claimant sued the defendants in negligence. At trial, all three defendants were found liable.

D3 appealed. He argued that he should not be liable as D2 should have realised he was prescribing the wrong drug. This was because, if the diabetes medication had been the correct prescription, the dosage was far too strong and the instructions for taking it were dangerously wrong. Additionally, the prescription was not free on the NHS, whereas diabetics were entitled to free medication. D3 argued that D2’s actions broke the chain of causation.

  1. Did D2’s misreading of the prescription break the chain of causation between D3’s actions and the claimant’s injury?

The Court of Appeal held that D3 was liable. Despite the factors D3 identified, it was still foreseeable that a pharmacist would misread the prescription and accidentally prescribe the diabetes medication. There was therefore no break in the chain of causation.

This Case is Authority For…

The unforeseeable actions of the third-party can break the chain of causation in the tort of negligence.


The court noted that it ‘is established law that a pharmacist has a duty to satisfy himself about any prescription which he makes up and, in case of doubt, to refer back to the doctor.’ Similarly, ‘a doctor who writes out a prescription for a patient owes a duty to the patient to write the prescription legibly’.