History of Medical Cannabis Availability in the UK

In the UK, cannabis is classified as a Class B drug, making its use and possession illegal.¹ Medical cannabis has a long history, but its modern legal journey in the UK began in earnest in November 2018, when legislation allowed specialist doctors to prescribe cannabis-based medicinal products (CBMPs) for use.²

NICE Guidelines and Prescribing on the NHS

The National Institute for Health and Care Excellence (NICE) has issued guidelines on the use of cannabis-based medicinal products.^*

These guidelines cover:

• Intractable nausea and vomiting
• Spasticity
• Severe treatment-resistant epilepsy^3,4

NICE recommends that these products be prescribed only when other treatments have not been effective and emphasizes the need for specialist oversight.^3,4

Private Prescriptions and Medical Cannabis
in the Workplace

Despite these guidelines, individuals are receiving prescriptions for medical cannabis from private clinics for other conditions not specified in the NICE guidelines and not following the recommendations of the NICE guidelines.⁵ Because of this, employees are increasingly approaching their employers to declare that they are in receipt of a medical cannabis prescription.

This poses a safety concern to employers since the prescribed cannabis often has a higher concentration of delta-9-tetrahydrocannabinol (THC), the psychoactive component that is present in street cannabis. Occupational health professionals are being asked to assess these individuals’ fitness for work due to the potential impairment impacts of their cannabis use.

Since medical cannabis is the same as ‘street’ cannabis it contains the same active component – THC. This makes medical cannabis use and street cannabis use indistinguishable in a drug test.

Medical Cannabis and Drug Testing
in the Workplace

An important question in workplace drug testing is whether medical cannabis use breaches the policy that a workplace has in place to reduce the risks from drug and alcohol misuse. A key safeguard in workplace drug testing is the Medical Review process, which ensures that positive test results are evaluated in the context of legitimate medical use. A doctor, (a Medical Review Officer or MRO) reviews the findings of the laboratory drug test. The MRO determines if there is a legitimate explanation for the drug test findings. The explanation is usually due to medication that an individual has been taking.

In workplace drug testing where an individual has declared medication use, the MRO must decide if the findings reflect the declared medication and if there is a legitimate explanation for the use of that medication. This is usually a straightforward process, where the individual can provide evidence that they have used over-the-counter medication or have taken medication prescribed by their doctor or used in some form of treatment.

Complications can arise when:  

• The medication is unlicensed or
• The prescription does not align with NICE guidelines

Most MROs will treat a private medical cannabis prescription that doesn’t follow the NICE guidelines using a licensed medical product as not legitimate, thereby ruling that the use of medical cannabis outside the NICE guidelines as a breach of a workplace drug and alcohol policy.

Network Rail’s Updated Drug
and Alcohol Standard

This approach has been reinforced by the most recent version of the Network Rail Drug and Alcohol Standard⁶ which states that the standard will be breached if an individual is

‘…working whilst using a medicine or drug which has no legitimate medical reason for use’

and that a drug test result will be treated as a positive result if

‘…the Medical Review Officer (MRO) determines that the findings are not justified by a legitimate medical reason.’

The Standard then goes on to define a ‘legitimate medical reason’ as ‘A licensed therapeutic medicine or treatment which is recognised within the British National Formulary (BNF).

Employer Responsibilities and
Employee Awareness

The concern is that some employees may be unaware that there is a problem with their medical cannabis use, since they were given it through a private prescription by a clinic.

Employers must therefore ensure that their employees are educated and aware of the implications of the use of unlicensed medication that can impact their ability to work safely.

*"Healthcare and other professionals are expected to take NICE clinical guidelines fully into account when exercising their clinical judgement. However, the guidance does not override the responsibility of healthcare professionals and others to make decisions appropriate to the circumstances of each patient, in consultation with the patient and/or their guardian or carer."⁷