Review and monitoring

A medicinal cannabis prescription in New Zealand does not end when the medicine is dispensed. Under the Medicinal Cannabis Scheme, which operates under the Misuse of Drugs Act 1975, a prescription is the beginning of an ongoing clinical responsibility. The Ministry of Health’s Medicinal Cannabis Agency (MCA), part of Medsafe, sets the rules for medicines and licensing, but the duty to review and monitor sits with the prescribing clinician (New Zealand Ministry of Health, 2023). What follows is a usable method for that clinical check: what to track, how often, and how to turn observations into a clear decision. It does not tell you what to take or how much; that decision belongs to your prescriber or pharmacist.

Review and monitoring: Why structured review matters

Medicinal cannabis is not a one-time prescription. The active compounds, THC (delta-9-tetrahydrocannabinol) and CBD (cannabidiol), affect people differently, and the right medicine and dose are found by titration, not by a single calculation. The New Zealand Medicinal Cannabis Scheme, run by the Ministry of Health and administered by Medsafe’s Medicinal Cannabis Agency, sets quality standards but does not dictate how a person should be monitored (New Zealand Ministry of Health, 2020). The NZ Formulary and peer-reviewed clinical guidance consistently recommend a structured review, usually 2-4 weeks after starting and then at agreed intervals, to check if the treatment is doing what the person wants, if it is causing harm, and if the dose should be adjusted.

The review is not a formality. It is the moment where the prescriber checks the three things that determine whether to continue: benefit, function, and adverse effects. the material below gives you a method to track those things between appointments, so the discussion is useful instead of vague.

What the law requires

Under the Misuse of Drugs Act 1975, medicinal cannabis is a controlled medicine, not a general licence to use cannabis. The Medicinal Cannabis Scheme, administered by the Ministry of Health and Medsafe, sets the legal pathway: a medical practitioner must issue a prescription, and the medicine must meet GMP standards and be approved by the Ministry of Health. The scheme does not legalise raw plant material for personal use; the only legal route is a prescription for a manufactured pharmaceutical dispensed through a pharmacy (New Zealand Ministry of Health, 2023). The thing newcomers most often get wrong is that “legal medicinal cannabis” does not mean a person can legally smoke raw plant material or buy unregulated preparations. Raw flower is available only through a prescription and dispensed by a pharmacy, never a dispensary.

Review and monitoring is the structured clinical discussion between the person and their prescriber after a prescription begins. It is not a one-off check; it is a repeatable process that tracks benefit, function and adverse effects. The NZ Formulary (2024) describes cannabis medicines as unapproved medicines, which means prescribers must take responsibility for the decision to prescribe, document the clinical rationale, and review the person at appropriate intervals. Medsafe, through the Medicinal Cannabis Agency, licenses medicines and sets quality standards under the Medicinal Cannabis Scheme (New Zealand Ministry of Health, 2020). There is no legal requirement for a fixed review interval, but the standard of care is to schedule a follow-up before the next prescription is issued.

What a review actually checks

A review is not a repeat of the first consult. It is a structured comparison between how the person functioned before starting medicinal cannabis and how they function now. The clinician should ask three questions, in order:

Benefit: Is the target symptom improved enough to justify continuing?
Function: Is the person doing more of what they need or want to do?
Adverse effects: Are side effects tolerable, manageable, or a reason to stop?

The discussion should be anchored to the original goal. If the goal was pain relief, the question is not “do you feel better?” but “what can you now do that you could not do before?” A person may report no change in pain score but improved sleep, mood or mobility. That is still a benefit worth recording.

How to structure the review appointment

A practical review session follows a simple structure:

Set the agenda: “We have 15 minutes. I want to cover how you’re sleeping, your pain or symptoms, any side effects, and if the current dose is still working.”
Ask about function, not just symptoms: work, driving, appetite, mood, sleep, and daily activities.
Ask about adverse effects: drowsiness, dizziness, gastrointestinal upset, dry mouth, changes in appetite or mood.
Review the actual medicine: what the person is using, how much, how often, and how they administer it (oil, flower, capsule, vaporiser).
Check for interactions with other medicines, alcohol or other substances.
Agree on the next step: continue, adjust dose, change medicine, or stop.

This six-step framework is a prompt for a structured clinical discussion, not a checklist for self-management. It is based on general clinical monitoring principles described in the NZ Formulary and the Medicinal Cannabis Scheme guidance (2023).

What the clinician should check

Each review should ask the same core set of questions, adapted to the person’s condition:

Pain score (0-10) or symptom score for the target condition
Functional change: sleep, appetite, work, daily activity, mood
Adverse effects: drowsiness, dizziness, dry mouth, gastrointestinal upset, appetite change, mood change, memory or concentration problems, signs of intoxication
Unwanted interactions: new medicines, alcohol, illicit drugs
Adherence: missed doses, medicine access, cost, practical difficulties
Medicine performance: if the current medicine, dose and route still fit the symptom pattern
Personal goals: if the original treatment goal is still relevant or needs updating

The clinician should also check:

if the medicine is working for the target symptom
if side effects are tolerable
if the dose is still appropriate
if the person is using the medicine correctly (for example, inhalation technique, oil under tongue)
if the person understands the legal boundaries (prescription only, pharmacy supply, no driving under impairment)
if the person is at risk of dependence or diversion
if the person is taking interacting medicines
if the person’s condition has changed and if cannabis is still the right treatment

A structured review should cover the same domains as the initial assessment (pain, sleep, mood, function, adverse effects) and use the same measurement tools so changes are comparable.

When to schedule reviews

A practical rule for deciding when to review: at 2-4 weeks after starting or changing a dose, then at 3 months, then every 3-6 months if stable. If symptoms have not improved by week 4, or adverse effects are unacceptable, the prescriber should adjust the dose or medicine. This is a pragmatic guide, not a legal rule; the prescriber sets the actual schedule. More frequent reviews are needed if the person is older, has multiple conditions, takes interacting medicines, or uses high-THC preparations.

What to measure and track

A practical rule for what to measure: a simple 0-10 scale for the primary symptom (pain, anxiety, spasticity, nausea, sleep) plus a functional question (“How many bad days in the last week?”) and an adverse-effect check. Keep a daily diary for the first two weeks of a new prescription. The diary should record: dose (mg and medicine name), time of day, symptom score (0-10), side effects, and any other medicines taken. Bring the diary to the first review, usually at 2-4 weeks.

A practical rule for interpretation: if the symptom score drops by at least 30% from baseline without unacceptable side effects, continue and review in 4 weeks; if the score drops less than 30% or side effects are intolerable, the clinician should adjust the dose or consider a different medicine (for example, change ratio, form, or route) rather than abandoning cannabis entirely. If there is no improvement after a fair trial (typically 4 weeks of consistent dosing at a therapeutic dose), the prescriber should reassess the indication. This is a clinical decision rule, not a guarantee.

If the person’s symptom scores have not improved by 4-6 weeks, the clinician should reconsider the medicine, dose, route, or diagnosis. If adverse effects are intolerable, the clinician should reduce the dose or change the medicine before abandoning medicinal cannabis. If the person reports no effect at a stable dose after 4 weeks, the clinician should check adherence, drug interactions, and medicine quality before assuming failure.

Questions to bring to the review

“What measurable changes have you noticed since starting or changing the medicine?”
“Which of your target symptoms improved, and by how much?”
“Are any new or worse symptoms appearing, such as drowsiness, dizziness, dry mouth, appetite changes, or mood shifts?”
“How is your sleep, appetite, energy, and ability to work or care for others?”
“Have you needed any rescue medication or unplanned medical care since the last review?”
“How consistent is your dose timing and method of administration?”
“Are you comfortable with the cost and the pharmacy process?”