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10 min read
Sarah Sinclair
Have you ever read the list of side-effects for a newly-prescribed medication and wondered whether it’s really safe to consume? Rest-assured that the drug has been through a lengthy and strict approval process before making its way to your local pharmacy.
Before any new medicine can be prescribed in the UK, it must go through a strict approval process.
In this article, we take a look behind the scenes at this process in action and explore the different stages of approving medicines in the UK, from research to market.
Cannabis-based medicines, which are becoming increasingly prevalent in modern healthcare, undergo their own unique regulatory pathway before being given the green light for prescription—we’ll get into this too.
Every medicine must go through the same strict approval process before it can be legally prescribed by UK clinicians. This involves carrying out extensive research and conducting clinical trials to prove it is safe and effective.
The Medicines and Healthcare products Regulatory Agency (MHRA) is the Government agency responsible for ensuring that medicines and medical devices prescribed in the UK are acceptably safe and effective.
As the main regulatory agency for UK medicines, the MHRA is responsible for overseeing the strict licensing approval process.
The Department of Health and Social Care makes decisions on which medicines should be purchased for the UK, and the National Institute of Clinical Excellence (NICE) decides whether or not medicines should be made available on the NHS.
The MHRA is the regulator of medicines, medical devices and blood components for transfusion in the UK.
It operates within a statutory framework set out by the Government and has a number of key responsibilities.
These include:
The European Medicines Agency (EMA) is responsible for the scientific evaluation, supervision, and safety monitoring of medicines in the EU, providing centralised marketing authorisations across all EU member states.
Since Brexit, the UK has established its own regulatory pathways, however, the MHRA and EMA continue to collaborate closely. The two bodies share safety information and cooperate on activities to monitor the safety of medicines in both jurisdictions.
The MHRA has also implemented procedures to recognise marketing authorisations granted by the EMA under certain circumstances in order to ensure medicines continue to be available for UK patients.
Both agencies are also part of international regulatory networks, such as the International Council for Harmonisation (ICH) and the International Coalition of Medicines Regulatory Authorities (ICMRA), which help harmonise standards and practices globally.
In January 2024, the MHRA introduced the International Recognition procedure (IRP)—a post-Brexit initiative designed to streamline the process for approving medicines by incorporating assessments from trusted regulatory partners worldwide.
Currently, medicines in the UK fall into two categories: licensed and unlicensed.
The MHRA decides whether medicines should be granted licences (also known as Marketing Authorisations), based on safety, quality, and effectiveness.
Licences confirm the health condition the medicine should be prescribed for and the recommended dosage. A licence for a medication will only be granted if all of the required safety and quality standards are met.
Sometimes clinicians prescribe ‘unlicensed’ or ‘off-label’ medicines. This means the product either doesn’t have a licence for use in the UK, or is not licensed for use in the condition for which it is being prescribed.
A doctor may prescribe an unlicensed medicine if they think it will treat your condition effectively, and they deem that the benefits will outweigh any potential risks.
Unlicensed medicines are often used in areas of medicine such as paediatrics, psychiatry and palliative care.
Here is the step-by-step outline of the process for bringing medicines from research to market in the UK:
Researchers identify potential new drugs and carry out preclinical laboratory and animal studies to evaluate its safety, efficacy, and biological activity.
Before clinical trials in humans can begin, the organisation must apply for authorisation from the MHRA and approval from the Research Ethics Committee. They are expected to include detailed information about the drug and proposed trials.
Once authorisation has been granted, clinical trials take place in three phases.
Phase I: Small-scale trials involving healthy volunteers to assess the drug's safety, dosage range, and side effects.
Phase II: Trials with a larger group of patients to evaluate the drug's efficacy and further assess its safety.
Phase III: Large-scale trials with a significant number of patients to confirm efficacy, monitor side effects, and collect data that will allow the drug to be used safely.
If clinical trials are successful, the organisation must submit a Marketing Authorisation Application to the MHRA, including data collected through the studies, as well as details on the manufacturing process, quality controls, and proposed labelling.
A team of scientists and clinicians at the MHRA then conduct a detailed evaluation of the data and a benefit-risk analysis.
The MHRA will carry out an inspection of the manufacturing facilities to ensure they comply with Good Manufacturing Practice (GMP) standards, as well as a quality assessment on the drug’s chemical composition, stability and manufacturing consistency.
Based on all of this data, the MHRA will make a decision about whether to grant Marketing Authorisation or not. In some cases, conditional approval may be granted, with requirements for further studies.
Even once a licence has been issued, the MHRA will continue to monitor it for any potential problems or previously unknown side effects. In rare cases, medicines may be withdrawn if there are serious safety concerns.
Since medical cannabis was legalised in 2018, cannabis-based products for medicinal use (CBPMs) are increasingly being prescribed privately in the UK.
While it is still the responsibility of the MHRA to ensure these are safe and of a high quality, as it stands, the regulatory pathway for CBPMs is a bit different to that of other medicines. This comes down to the fact as it stands, the majority of these products are unlicensed and imported from other countries.
The majority of CBPMs prescribed in the UK are unlicensed, as they have not been through the necessary clinical trials for Market Authorisation.
Only three CBPMs have a marketing authorisation; these are Sativex, Epidyolex and Nabilone.
Licensed CBPMs are recommended from prescription through the NHS in certain conditions, such as multiple sclerosis (MS), rare forms of epilepsy and chemotherapy-induced nausea and vomiting.
Unlicensed CBPMs can only be prescribed by doctors on the specialist register and are generally only accessible through private specialist clinics. When doctors choose to prescribe these medicines to patients, they accept full responsibility.
As with any other medicine, CBPMs must go through the stages set out above in order to obtain Market Authorisation. This process is lengthy and can be very expensive, so since the law change no new CBPMs have been licensed for prescription in the UK.
So how do unlicensed CBPMs get approval?
According to MHRA guidelines, only certain people are authorised to procure unlicensed CBPMs in the UK.
These include:
A number of UK companies are in the process of developing CBPMs for prescription.
Any manufacturer intending to cultivate cannabis for medicinal use in the UK must obtain a Controlled Drug Licence from the Home Office. They must also apply for a licence from the MHRA, which will carry out an inspection of the facility to ensure it is GMP compliant.
However, as the majority of CBPMs are imported from other countries, these are subject to a different process again.
Once a doctor has written a prescription for an unlicensed cannabis medicine, they must apply to the MHRA for a licence in order for the product to be imported. This import application includes detailed information about the patient, the medical condition being treated, the proposed treatment plan, and the specific product being requested.
The MHRA will review the application to ensure compliance with regulatory requirements and assess the risks and benefits of the proposed treatment.
The specialist importer must hold either a Wholesale Dealer’s Licence or a Manufacturer’s (Specials) Licence. They must notify the MHRA at least 28 days prior to the intended import, providing details such as product name, manufacturer information, quantity, and content/ratio of THC/CBD. If the application is approved, the product can be legally imported into the UK, following customs clearance procedures.
Most CBPMs arrive in the UK as 'Schedule 2' finished products, however some are imported as raw materials under 'Schedule 1', which are then repackaged or processed domestically.
You can read more about how medical cannabis is regulated in the UK here.
Only doctors on the General Medical Council (GMC) specialist register—consultants or ‘specialists’ such as neurologists, psychiatrists, and rheumatologists — are permitted to prescribe unlicensed CBPMs.
They can be prescribed for more or less any condition if it is deemed to be in the best interests of the patient, but prescribing criteria generally requires a patient to have tried two previous treatments without success.
While a few patients have been issued with NHS prescriptions for unlicensed CBPMs, the majority are prescribed through private clinics, such as Releaf.
If you’re looking for an alternative to conventional medicine, you can use Releaf’s free eligibility checker to see if cannabis-based treatments would be right for you.
It is important to seek medical advice before starting any new treatments. The patient advisors at Releaf are available to provide expert advice and support. Alternatively, click here to book a consultation with one of our specialist doctors.
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Am I eligible?Sarah, a distinguished journalist with over a decade in publishing and communications, now excels in cannabis health and policy journalism in the UK, advocating for informed health decisions through her award-winning work.
Our articles are written by experts and reviewed by medical professionals or compliance specialists. Adhering to stringent sourcing guidelines, we reference peer-reviewed studies and scholarly research. View our editorial policy.
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