Benzoylecgonine

Your body starts to metabolise the cocaine and produce BZE about 15 - 30 minutes after cocaine administration.

A dose of 100mg cocaine (snorted) the half-life of BZE was reported to be 4-6 hours and the window of detection up to approximately 30 hours and for at least 5 days in chronic user (Wolff report 2013)

When cocaine and BZE are detected together the level of BZE was usually higher than the cocaine level. BZE alone tends to be lower. When found together it is indicative of use within the last 12 hours.

BZE alone tends to indicate cocaine use in the past few days. 

BZE and Driving

Cocaine is a very fast acting drug and the Wolff report stated that a threshold for cocaine alone might miss many cases of cocaine use where a driver could still be under the influence of the drug. BZE alone at higher levels could indicate that the driver is on the “come down” so driving would still be affected.

However, the Wolff panel recommended that the level should be so high as to exclude the possibility of having taken cocaine days before when you would not be affected or on a “come down”. Their recommendation was 500ug/L but the government set it at a zero tolerance level of 50ug/L. It highly unlikely that below 500ug/L a driver would impaired by the “come down”.

Drivers must be alert to the “zero level” of BZE and the length of time BZE can be detected in your system. If you drive for a living and your livelihood depends on your driving licence, you should not take cocaine if you need to drive within the next 5 days because you may be over the specified limit for BZE despite the cocaine having been completely eliminated from your system.

Defences for driving over the limit for BZE

Laboratories have struggled to effectively analyse blood samples. There have been two laboratories recently which have lost their accreditation due to errors in their analysis of blood samples. Approximately 4,000 cases have been re-opened and convictions set aside as a result.

It is not a perfect science and you cannot assume that the prosecution analysis is 100% accurate it isn’t.

In recent cases we have experienced issues in blood analyses for cocaine and BZE with one toxicologist pointing out the levels of cocaine and BZE were inconsistent with each other and in order to present these corresponding levels our client would have to have been dead, which fortunately he wasn’t. In fact it was an example of cross contamination at the laboratory.

What to look for?

There a number of tell tale signs in the analytical data pack (ADP) which would indicate the result are unreliable.

• Has the laboratory deducted the 20% allowance from the result – this is the allowed margin of error. If not then your result may be below the specified level.
• Does the laboratory have the proper accreditation which is the validation process which examines their processes to ensure their accuracy in analysing blood samples. There is an accepted 30% allowance between laboratories. Such an allowance suggests that if another laboratory tested the same sample it could come back 30% lower and that is difficult to challenge.
• Poor labelling and lack of continuity. All vials must be labelled correctly and followed through the analysis sometimes this gets muddled up and the prosecution cannot prove that the sample tested was the defendants.
• Has the data input been accurate if there is a “data anomaly” it will usually lead to inaccurate results.
• Failings in the quality control sample – each batch of samples must have a control sample to be measured against if this is contaminated in any way the whole batch would usually need to be re-tested but usually isn’t. Such contamination would lead to higher results and render the results unreliable.
• Have they calibrated the results and equipment accurately. The laboratories must test and calibrate their analytical instruments daily. These results must fall within a recommendation range or standard deviation. These are resulted in the form of graphs on the ADP which can be examined and the deviation checked to see if they fall within the recommended range if not the batch should have been re-tested because the results will not be reliable. Laboratories seldom re-test because it is not profitable to do so their margins for profit are so small.
• There are added complications with BZE because if there are traces of cocaine left in your blood sample it can increase the levels of BZE in your system. This should be considered if you only have BZE in your system. There are a lot of factors that affect the ratio of cocaine and BZE and the respective levels:
  Temperature – At room temperature, BE can increase significantly (~50-100% in a few days). Refrigeration slows the increase (~10-20% per week). Freezing (-20°C or below) minimizes the increase (~5-10% over months).

  Natural increases over a period of time

  Preservatives which can increase the levels of BZE

Procedural Issues

The prosecution must follows the procedure to the letter, there include:

1. Compliance with S15 Road Traffic Offenders Act 1988 which specifies how blood samples should be taken and what should be done with them after.
   https://roadtrafficdefencelawyers.co.uk/2023/03/14/the-importance-of-keeping-your-blood-sample-taken-by-the-police/
2. Lack of continuity of the sample. The police must be able to show that the sample tested was your sample and failure to label correctly can break the continuity and offer a defence.
3. Failure to disclose evidence which will assist the us as the defence or undermine the prosecution case. The prosecution often fail to serve evidence within a specified period of time and this can lead to arguments to exclude vital prosecution evidence such as the expert report.

Post Driving Consumption

Many drivers say that when the police are indicating them to stop driving, they panic because they are in possession of some cannabis so having stopped their vehicle and before the police reach them they eat the cannabis.

This is a defence but we would have to prove this on a balance of probabilities. We would have to show that but for the cannabis eaten you would have been under the limit. If done successfully you would be found not guilty and your case would be dismissed.

The police may have body worn video evidence which will either show that you may have taken cocaine or had the time to take cocaine. Equally it may also show that it was impossible for you to take the cocaine.

You will usually need expert evidence to show that but for the cocaine taken after driving you would not have been over the limit.

If you have taken drugs after being stopped then you should tell the police. It makes the argument of post driving consumption more believable.

It would be unusual if you had consumed cocaine immediately after driving to just have BZE in your body if your sample was taken within 3 hours of have consumed the cocaine. BZE alone is normally indicative of cocaine use quite a while before the blood sample was taken usually over 12 hours.

Special reasons and cocaine

Special reasons can be argued where you have unwittingly taken cannabis in order to avoid the mandatory minimum 12 months ban.

• Medication containing cocaine - some medications may contain cocaine and this can be examined by one of our experts. It may also be applicable if you had surgery recently. Remember unless prescribed this will not be a statutory defence. You would have had to be unaware that you had taken cocaine.
• Laced drinks - usually you would have get the lacer to give evidence or provide some evidence to show that your drinks were laced. You would also have to produce expert evidence to show that but for the lacing element you would have been under the limit. This is easier to establish if you do not use drugs at all.
  

Reference

1. Symptoms and Signs of Substance Misuse 3rd edition Margaret Stark, Jason Payne-Jamesm Michael Scott-Ham
2. Wolff Report 2013