What a prescriber considers

When a New Zealand medical practitioner considers prescribing medicinal cannabis, they weigh evidence, safety, legality and the patient’s own goals in a structured conversation. Under the Misuse of Drugs Act and the Medicinal Cannabis Scheme run by the Ministry of Health, prescribing is a regulated clinical act, not a general licence to use cannabis, and not a “natural cure” shortcut.

The sections below walk through the factors a prescriber weighs, the evidence they consult, and the questions they will ask. The goal is to help you prepare for that conversation, not to replace it. Whether you should take cannabis, and which preparation is right for you, is a decision that belongs to your doctor or specialist.

The regulatory frame

A prescriber in New Zealand is not free to hand out cannabis like a supplement. The Medicinal Cannabis Scheme, administered by the Medicinal Cannabis Agency (part of Medsafe), operates under the Misuse of Drugs Act 1975. Since 1 April 2020, the framework has allowed medical practitioners to prescribe cannabis-based preparations that meet GMP (Good Manufacturing Practice) standards and are approved by the Ministry of Health (Medsafe, 2020).

The key legal point: a prescription is required for every legal medicinal cannabis preparation. There is no “over-the-counter” cannabis, and there is no legal pathway for a patient to self-select a raw plant and have it dispensed as if it were a herbal remedy. Even the raw flower, when prescribed, is a manufactured pharmaceutical dispensed through a pharmacy, not a dispensary.

The Misuse of Drugs Act 1975 (as amended by the Misuse of Drugs (Medicinal Cannabis) Amendment Act 2018) sets the framework, and the Medicinal Cannabis Agency (MCA), part of Medsafe, oversees the system. Since the framework’s full commencement on 1 April 2020, preparations must meet GMP standards and be approved by the Ministry of Health. This is the legal baseline every prescriber works within.

What “legal medicinal cannabis” actually means

The thing newcomers most often get wrong is that “legal medicinal cannabis” does not mean a patient can legally smoke raw plant material or buy unregulated goods. The legal options are manufactured pharmaceuticals, oils, capsules, or dried flower for vaporisation, dispensed through a pharmacy against a prescription. Prescribers must choose from preparations notified to the Medicinal Cannabis Agency, which are listed on the New Zealand Formulary and meet GMP standards. Items that have not been notified cannot be prescribed legally under the framework. The raw plant material a patient might obtain elsewhere is not part of this pathway, and smoking raw flower is not a legal route to medicinal cannabis under New Zealand law. (Source: New Zealand Ministry of Health, Medicinal Cannabis Scheme, 2020; Medsafe, 2020.)

How the system is administered

Medsafe, the New Zealand regulator, oversees approvals. The Medicinal Cannabis Agency (MCA), part of Medsafe, issues licences to importers, manufacturers and suppliers. The NZ Formulary includes cannabis monographs, and the New Zealand Ministry of Health publishes the regulations. Under the Misuse of Drugs Act 1975, prescribing cannabis-based preparations is legal when the item meets the requirements of the Medicinal Cannabis Scheme, which came into force on1 November2020 (New Zealand Ministry of Health, 2020). The framework legalises access via a prescription from a medical practitioner, and items must meet Good Manufacturing Practice (GMP) standards and be approved by the Ministry of Health.

What a prescriber actually weighs up

A prescriber does not start with the preparation. They start with the person, the condition, and the evidence. The decision to prescribe medicinal cannabis under the Medicinal Cannabis Scheme is a clinical judgement, not a checkbox. Under the Misuse of Drugs Act and the Medicinal Cannabis Scheme, a medical practitioner can prescribe a controlled drug, but they must do so within the same duties of care as any other medicine: assess, inform, monitor, and document.

The core question a prescriber asks is not “does cannabis work?” but “is this the right treatment for this person, at this time, given what else has been tried and what could go wrong?”

The prescriber’s starting question

When a prescriber considers medicinal cannabis, they are not deciding “should this patient use cannabis?” They are answering a narrower question: does this person have a condition where the evidence supports a trial of a specific cannabinoid preparation, and can they be monitored safely?

In New Zealand, the legal framework is set by the Misuse of Drugs Act and the Medicinal Cannabis Scheme, administered by the Ministry of Health and Medsafe. Under the framework, a medical practitioner can prescribe a CBD or THC preparation that meets GMP standards and has been notified to the Ministry of Health. The prescriber must weigh the same factors as for any pharmaceutical: the strength of the evidence, the patient’s other medicines, the risk of adverse effects, and whether the goal is realistic. The system does not create a general right to use cannabis; it creates a regulated clinical pathway.

Indications and the “last resort” framing

A prescriber will confirm the indication is one with at least some peer-reviewed clinical evidence. Conditions that commonly appear include chronic pain, cancer-related symptoms, refractory epilepsy, palliative care, and spasticity in MS. They will also confirm the patient has exhausted or not tolerated conventional treatments. This is the “last resort” framing most prescribers use.

Safety screening and contraindications

Before writing a prescription, the prescriber screens for contraindications. These include pregnancy or breastfeeding, a personal or family history of psychosis or schizophrenia, unstable cardiac disease, severe liver impairment, and current substance use disorder. They also check for drug interactions. THC and CBD are metabolised through CYP3A4, CYP2C19 and CYP2C9 pathways, so the prescriber will review medicines such as warfarin, clobazam, olanzapine, ketoconazole, rifampicin, alcohol and other sedatives.

Choosing a preparation and dose

The prescriber matches the form to the need: inhaled for breakthrough symptoms, oral oils for maintenance. They match the THC:CBD ratio to the dominant symptom. The rule is “start low and go slow”: prescribe a low dose, titrate by25% every3 to7 days, and monitor for adverse effects.

Documenting and monitoring the plan

The prescriber documents the treatment plan: indication, preparation, dose, titration schedule, review date, and a “stop rule” if no benefit after a defined trial. At follow-up they monitor pain scores, sleep quality, mood, adverse effects, and interactions with existing medicines.

The prescribing decision framework

A prescriber in New Zealand follows a structured sequence. The checklist below summarises what they work through.

1. Confirm the indication has peer-reviewed clinical evidence (chronic pain, cancer-related symptoms, refractory epilepsy, palliative care, spasticity in MS).
2. Confirm the patient has exhausted or not tolerated conventional treatments.
3. Screen for contraindications: pregnancy or breastfeeding, personal or family history of psychosis or schizophrenia, unstable cardiac disease, severe liver impairment, current substance use disorder.
4. Check for drug interactions: CYP3A4, CYP2C19, CYP2C9 inhibitors or inducers; warfarin, clobazam, olanzapine, ketoconazole, rifampicin, alcohol, sedatives.
5. Choose the form based on onset and duration: inhaled for breakthrough, oral oils for maintenance; match THC:CBD ratio to the dominant symptom.
6. Start low and go slow: prescribe a low dose, titrate by25% every3 to7 days, monitor for adverse effects.
7. Document the treatment plan: indication, preparation, dose, titration schedule, review date, and a “stop rule” if no benefit after a defined trial.
8. Monitor at follow-up: pain scores, sleep quality, mood, adverse effects, and interactions with existing medicines.
9. Re-check contraindications: unstable cardiovascular disease, current substance use disorder, pregnancy or breastfeeding, and a history of cannabis-induced psychosis.
10. Re-check drug interactions: CYP3A4 and CYP2C19 inhibitors or inducers (e.g., clobazam, warfarin, olanzapine) can raise or lower levels of THC and CBD.