How to Write a Cannabis Prescription: A Clinician’s Guide

Legal Framework for Prescribing Cannabis in the UK

• Schedule 2 rescheduling of cannabis in November 2018 permits prescribing by specialist physicians on the GMC register
• Cannabis-based products for medicinal use (CBPMs) must meet MHRA quality standards for importation
• Prescriptions must be written on FP10PCD (England) or equivalent controlled drug prescription forms
• Prescribers must hold a relevant specialist qualification; GPs currently cannot initiate cannabis prescriptions independently

The legal framework governing cannabis prescribing in the UK has evolved significantly since 2018. Prescribers must operate within the current controlled drug regulations, which require that cannabis prescriptions are written correctly to be dispensed by licensed pharmacies. An incorrectly completed prescription will be rejected at the pharmacy and cause unnecessary delays and distress for patients.

Essential Elements of a Valid Cannabis Prescription

• Patient full name, address, and date of birth must appear on the prescription
• Drug name (generic or trade), form, strength, dose, frequency, and quantity in words and figures
• Prescriber’s name, address, GMC number, and signature in ink
• Date of prescription; most pharmacies will not dispense more than 28 days after the date of issue

Cannabis prescriptions are subject to the same controlled drug prescription requirements as other Schedule 2 substances. Prescribers who have not previously prescribed Schedule 2 drugs should familiarise themselves with the legal requirements before initiating cannabis prescribing. Incomplete or incorrectly written prescriptions are a common cause of dispensing failure and patient frustration.

Specifying the Cannabis Product: What to Include

• Product name and batch number where possible to ensure dispensing of the correct product
• Strain name, THC percentage, CBD percentage, and total weight (grams) for flower products
• Route of administration: vaporisation, oral oil, or other approved method
• Special instructions: “to be vaporised only” where appropriate to avoid patient confusion

The level of specificity required in a cannabis prescription goes beyond standard pharmaceutical prescribing. Because cannabis products are not uniformly standardised across batches and suppliers, prescribers should be as specific as possible about the product they are recommending. Building a relationship with the dispensing pharmacy and communicating prescribing intentions proactively helps to ensure patients receive the correct product.

Common Errors and How to Avoid Them

• Writing the quantity in figures only — the law requires both words and figures for Schedule 2 drugs
• Failing to specify the route of administration, creating ambiguity at the pharmacy
• Using unstandardised product names that the dispensing pharmacy cannot identify or source
• Signing in pencil or allowing unsigned prescriptions to reach the patient — both are illegal

Prescribing errors in cannabis medicine carry both legal and clinical consequences. Clinicians new to cannabis prescribing are strongly advised to attend a CBPM prescribing training course and to familiarise themselves with their local pharmacy’s formulary and dispensing capabilities before writing their first prescription. Clinical governance frameworks within prescribing organisations should include cannabis prescription audit as standard.