If your prescribed medical cannabis plan is not working as expected, or side effects are becoming a problem, contact your clinic before making changes yourself. The useful first step is to collect clear information, explain what is happening, and let the prescriber decide what is clinically appropriate.
This article is for already-prescribed patients who are preparing for a review or clinic message. It does not tell you to alter the prescribed amount, timing, product, route or frequency. It does not recommend a clinic, pharmacy, product or dose. For wider context, read the MCPH patient guide and medical cannabis side effects.
The short answer
Before changing anything, write down:
- what concern has prompted the review;
- when the issue started;
- what symptoms, side effects or daily-function changes you have noticed;
- the product label details for the medicine you were prescribed;
- whether anything else changed, such as another medicine, illness, alcohol, sleep, work or stress;
- any missed doses, delayed deliveries, label questions or pharmacy messages;
- the exact question you want the clinic to answer.
Then contact the clinic through the route they gave you. If symptoms are severe, urgent or feel unsafe, use NHS urgent routes instead of waiting for a routine private-clinic response.
Why the prescriber needs to be involved
Medical cannabis is prescribed as part of a clinical plan. The prescriber is responsible for balancing potential benefit, side effects, medicine interactions, impairment, mental and physical health risk factors, and the practical reality of your condition.
Changing a plan without review can make the picture harder to interpret. If symptoms improve, worsen or side effects appear, the clinic needs to know what happened while the medicine was being used as prescribed. If the record is mixed with unagreed changes, it can be harder to judge safety and response.
This is not about blame. Patients often notice problems between appointments. The boundary is simple: record the problem and ask for review; do not make a private treatment plan from an article.
Reasons to contact the clinic
Common reasons include:
- side effects such as dizziness, tiredness, anxiety, confusion, hallucinations, nausea or appetite changes;
- no useful change in the symptom the medicine was meant to help;
- the medicine feeling too sedating or affecting daily function;
- worries about driving, work, caring duties or safety-critical tasks;
- another medicine being started, stopped or altered by a clinician;
- a new health issue, pregnancy, breastfeeding, infection or hospital admission;
- product-label confusion, stock-change messages, delivery delays or pharmacy queries;
- cost or access problems that affect whether the plan can be followed as prescribed.
NHS medical cannabis guidance says CBD and THC can affect how other medicines work. Interaction questions are normal prescriber and pharmacist territory, not something patients need to solve alone.
What to record before you message
Keep the message clear and practical. A clinic can usually respond better to a short structured note than to a long emotional account with no dates.
Include:
- your name and date of birth, if the clinic portal asks for it;
- the date the concern started;
- the medicine name and label details;
- what you have taken as prescribed and what was missed, delayed or unclear;
- symptoms and side effects, with rough timing;
- any urgent symptoms or safety concerns;
- any other medicine, supplement, alcohol or health changes;
- what you are asking the clinic to decide.
If you have a symptom diary, attach or summarise the useful part. For a simpler record, see what to track after starting prescribed medical cannabis once that article is published.
What not to do while waiting
Do not use an article to design your own adjustment. Do not test leftover products, compare old prescriptions, ration medicine, combine products, use non-prescribed cannabis to cover a delay, or follow another patient’s plan.
If the concern is side effects or safety, tell the clinic what is happening and ask what they want you to do. If the concern is urgent, use NHS 111, 999 or another urgent route according to severity.
If you cannot get a timely clinic response and the situation is affecting safety, speak to an appropriate healthcare professional rather than trying to manage the risk privately.
What the clinic may need to decide
The clinic may decide to:
- gather more information first;
- arrange a review appointment;
- ask for pharmacist input;
- check interactions or risk factors;
- update written instructions;
- advise urgent or routine NHS care for symptoms outside the clinic’s scope;
- decide whether the current plan remains suitable.
The article cannot predict the outcome. It can only help you prepare the information needed for that decision.
Questions to ask before any agreed change
Good questions keep the decision with the prescriber:
- What problem are we trying to solve with this review?
- Which side effects or safety signs need prompt contact?
- Do any of my other medicines need pharmacist review?
- What should I record after the decision?
- How soon should follow-up happen?
- Who should I contact if the written instructions and product label do not match?
- Does this affect driving, work, caring duties or other safety responsibilities?
If the clinic recommends a change, ask for the plan in writing. That helps avoid confusion later.
When to use urgent help
Use urgent NHS routes for severe confusion, chest pain, severe breathlessness, fainting, symptoms of stroke, a serious allergic reaction, suicidal thoughts, severe agitation, psychosis-like symptoms or any situation where you feel immediately unsafe.
For less urgent but worrying side effects, contact the prescribing clinic and follow the route they gave you. Keep a record of what you reported and when.
For related reading, see medical cannabis and medication interactions and THC side effects and impairment.
Sources
- NHS: Medical cannabis
- NICE: Cannabis-based medicinal products, NG144
- NHS England: Cannabis-based products for medicinal use
- GMC: Information for doctors on cannabis-based products for medicinal use
- GMC: Prescribing unlicensed medicines
- CQC: Cannabis-based medicinal products: what we look at when we register
- MHRA: Off-label or unlicensed use of medicines: prescribers’ responsibilities
- MHRA: Supply unlicensed medicinal products, specials
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