GP training: 5 common prescribing pitfalls and how to avoid them

MDU medico-legal adviser Dr Beverley Ward highlights the five most common prescribing errors in general practice.

Over a billion prescriptions were issued by the NHS in one year from July 2014 to June 2015,1 so it’s hardly surprising that prescription errors are still one of the most common reasons for a claim notified to the MDU.

A recent analysis of MDU claims files over a five year period from 2011-2015 revealed there were 217 clinical negligence claim cases attributed to prescribing errors, the majority of which involved GPs.2 Most prescribing errors do not cause any significant harm to the patient, and over 60% of these claims were successfully defended, but despite this, the error can cause great anxiety for the patient and prescriber.

The five most common prescribing pitfalls in claims are the following:

1.Prescribing a drug to someone with a known allergy

This was the most common error resulting in a claim. Penicillins were the most common drug involved.

Patients cannot always give a reliable history in relation to drug allergies, so it’s important to ensure that you also check the records for reported allergies, and to see what drugs have been prescribed in the past. Appropriate systems need to be in place to flag allergies in a way easily visible to doctors accessing the records.

Always document that you have asked the patient about allergies in case you need to defend your prescribing decision later. 

2. Prescribing the wrong drug

In the past, wrong drugs were sometimes dispensed by pharmacists due to difficulty in deciphering a doctor’s handwriting. These days, computer generated prescriptions avoid this risk, and the error is usually made by the GP choosing the wrong drug from the drop down menu on the computer system. Examples include choosing penicillamine instead of penicillin, or choosing the wrong route of administration, e.g. ear drops instead of eye drops.

3. Prescribing the wrong dose

This can also easily happen when choosing from a drop down menu, where a drug is listed with different preparations and strengths. Or a GP may simply choose the wrong dose for that particular patient in those circumstances.

There is a particular risk when prescribing for children or the elderly, who may require smaller doses, or where the dose may need to be calculated based on body weight.

There have been several claims cases involving opiates, where a higher than intended strength was prescribed, resulting in an overdose. One patient developed hypoxic brain injury following a cardiac arrest, and this case resulted in a compensation payment of nearly £2m. Another common error was prescribing a drug at the wrong frequency, for example methotrexate daily instead of weekly.

4. Failing to consider drug interactions, side effects and contraindications

Complaints and claims can arise when attention is not paid to possible interactions with other drugs the patient is taking or being prescribed. Side effects can develop, or the situation changes meaning that drug is no longer appropriate such as when a patient on a long term anti-epileptic therapy  becomes pregnant.

5. Failing to monitor appropriately

Some drugs require monitoring because they have a narrow therapeutic range, such as phenytoin. Others, more commonly, require investigations to inform dose as with thyroxine and warfarin. Some drugs require monitoring to look for side effects, for example checking renal function in patients taking ACE inhibitors.

A study published in the BMJ in 2015 found that around one in 100 patients from 526 UK general practices included in the study were at risk of receiving an inappropriate prescription and around one in 250 had no record of monitoring within the recommended time period.3 The elderly, and those with multiple repeat prescriptions were most at risk.

How to avoid risks

The GMC provides detailed guidance on prescribing, and states that doctors must be familiar with and follow prescrining guidance and take account of relevant national guidance.

You should prescribe medicines only if you have adequate knowledge of the patient’s health and you are satisfied that they serve the patient’s needs. You must also make sure that suitable arrangements are in place for monitoring, follow-up and review, taking account of the patients’ needs and any risks arising from the medicines.

Awareness of the risks involved in prescribing helps to ensure safe practice, but errors do still happen. If you become aware of a prescribing error, contact your medical defence organisation for advice.


  3. Stocks, JS et al. Examining variations in prescribing safety in UK general practice: cross sectional study using the Clinical Practice Research Datalink. BMJ 2015; 351: h5501

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