Drug Driving

It is not recommended to drive after having taken drugs as your driving might be affected, but it is now also illegal to drive with specified levels of certain drugs in your blood, if you have not been prescribed them or have not followed the advice given to you about how to take them.  If you have been prescribed the drugs and followed the advice, even if you have higher than the allowed amount in your blood you can still drive as long as your driving is not affected (impaired).

If you are convicted of this offence you will be banned from driving for at least 1 year, and may also be fined an unlimited amount of money and/or face up to 6 months in prison.

The table below sets out the levels and addresses potential timeframes for elimination from the body/detection in blood (only blood is referred to as this is what will be tested).

The law about levels of drugs in the body is used as well as the law about being unfit to drive through drugs – it DOES NOT REPLACE IT. Your fitness to drive is assessed by a police officer at the side of the road by asking you to do certain activities. Drugs in your system might be used as evidence to support the charge. It is still illegal to drive if your driving is affected (impaired) after using drugs, even if you are below the set limit.

Below is a table of the set limits with some information about how long they might last in your system. If you have a specific question please contact our expert drugs and legal advisers on 0207 324 2989 or ask@release.org.uk

NOTE: THESE ARE APPROXIMATE TIMES ONLY AS ELIMINATION AND DETECTION TIMES ARE DEPENDENT ON A WIDE RANGE OF FACTORS, INCLUDING BUT NOT LIMITED TO: GENDER; AGE; BUILD/BODY COMPOSITION; DOSAGE; HISTORY AND FREQUENCY OF USE.

Controlled drug

Limit (mcg/L blood)

Comments

Elimination/detection times (other factors apply)

Benzoylecgonine (BZE)

50

This is the main metabolite of cocaine and what is tested for when analysing for cocaine
  • Following a dose of 100 mg cocaine (snorted) the window of detection is reported to be up to approximately 30 hours, and for chronic users at least 5 days
  • However, after a single dose only likely to be detectable for 3-12 hours, BUT highly unlikely to be completely clear after just 3 hours and likely still ‘under the influence’ at that stage

Clonazepam

50
  • Rapidly absorbed, peak effects 3-4 hours after taking an ‘average’ dose orally
  • Panel research found an increase in traffic accidents among people with three or more benzodiazepine prescriptions
  • Likely to be below the cut-off for detection after 2 days after a single dose
  • HOWEVER, people prescribed this are likely to be taking them every day, so likely to be permanently present in the system

Cocaine

10
  • Research shows cocaine (as itself rather than the metabolite benzoylecgonine, see above) is eliminated from the body fairly quickly, so its presence is likely to indicate recent use of cocaine

After a single average dose (see BZE), not likely detectable at the set level after 12 hours; for heavy/repeated use could be 24-48 hours

Delta-9-Tetrahydrocannabinol

2
  • This is the main psychoactive ingredient of cannabis
  • The window of detection after a single dose would be quite narrow – usually 9 to 12 hours
  • However, because of the very low level set, frequent/heavy users will have a store in their system that can re-release so may test positive after many days even if they haven’t used

Diazepam

550
  • At an ‘average’ dose of 5-15mg, peak effects 15-90 min (so not safe to be driving this soon after due to sedative effects)
  • Panel research found an increase in traffic accidents among people with three or more benzodiazepine prescriptions
  • In most people it would be eliminated after around 30 hours
  • HOWEVER, people prescribed these are likely to be taking them every day, so likely to be permanently present in the system

Flunitrazepam

300

Panel research found an increase in traffic accidents among people with three or more benzodiazepine prescriptions
  • Peak concentrations occur in the body after about 1 hour following a single dose, or 3 hours after daily dosing for a month
  • HOWEVER, people prescribed these are likely to be taking them every day, so likely to be permanently present in the system

Ketamine

20
  • If smoked the onset of effects is immediate
  • If snorted effects begin 1‐5 minutes after dosing
  • If ingested 15‐20 minutes after consumption
  • A standard street‐dose of ketamine is typically around 125 mg (⅛ g), which would create a level of 200mcg/L in most adult males (for females harder to judge as less studies have been done on them but likely to be slightly lower on average)
  • Studies show that at 200mcg/L elimination should be within 6 hours, so at the level set it will take much longer

Lorazepam

100
  • Panel research found an increase in traffic accidents among people with three or more benzodiazepine prescriptions
  • At 4mg ‘average’ dose, this would likely be eliminated after around 24 hours
  • HOWEVER, people prescribed these are likely to be taking them every day, so likely to be permanently present in the system

Lysergic Acid Diethylamide

1
  • The level is so low it is effectively zero tolerance
  • Detection time is irrelevant given the level set

Methadone

500

—
  • Very dose dependent, but concentrations have been shown to peak at around 850 mcg/L about 4 hours after a dose of 100‐120 mg, then fallen to below 500 mcg/L (the cut-off) after 24 hours
  • HOWEVER, by its nature as a maintenance drug, very few users are likely to not have taken any for more than 24 hours, so may therefore have detectable levels

Methylamphetamine

10

—
  • Likely to be eliminated after around 24 hours
  • HOWEVER, the extremely low threshold will make detection possible a long time after the effects have worn off

Methylenedioxymethamphetamine (MDMA)

10

—
  • For just MDMA, after a ‘moderate’ single dose (<100mg) it should be eliminated after around 24 hours
  • HOWEVER, the window of detection after a high dose would be up to 38 hours, and even longer for multiple dosing

6-Monoacetylmorphine

5
  • This is one of the 3 active metabolites of heroin, commonly known as 6‐MAM
  • Morphine is a metabolic breakdown product of 6-MAM

Detection is most likely between 30 minutes and two hours after a single dose

Morphine

80
  • Possibly included because of the short detection time for heroin and 6-MAM
  • Morphine is a metabolic breakdown product of 6-MAM

Very dose dependent but the window of detection would be up to 10 to 15 hours after ingestion of a single ‘average’ dose

Oxazepam

300
  • This is a metabolite of several other benzodiazepines including chlordiazepoxide, diazepam, desmethyldiazepam (nordiazepam) and temazepam so in theory any of these could show up
  • Panel research found an increase in traffic accidents among people with three or more benzodiazepine prescriptions
  • Likely eliminated after around 18 hours
  • HOWEVER, people prescribed these are likely to be taking them every day, so likely to be permanently present in the system

Temazepam

1,000
  • Temazepam is a metabolite of several benzodiazepines, including diazepam, and is itself demethylated to oxazepam, so in theory all could show up
  • Panel research found an increase in traffic accidents among people with three or more benzodiazepine prescriptions
  • Likely eliminated after around 12 hours
  • HOWEVER, people prescribed these are likely to be taking them every day, so likely to be permanently present in the system

If you have been arrested or charged for a drugs offence call or email us for free and confidential advice.

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