Prescribing medicinal cannabis: An FAQ for medical professionals

“What should I consider when it comes to prescribing medicinal cannabis?”

This is a question we hear from doctors across the country who are interested in alternative pain medicines for their patients, and one we need to spend more time educating doctors, prescribers, and the wider public about.

Due to the relatively new emergence of medicinal cannabis products in our healthcare system, we need to ensure those who are interested in prescribing them have a strong understanding of the products, and confidence in what they’re recommending to patients.

What are the key contraindications to be aware of when prescribing?

Like every prescribed medicine, a one-size-fits-all model is never the right solution for patients and this rings true for medicinal cannabis.

There are a range of factors to be considered including past medical history – especially cardiovascular, renal and liver issues – mental health history, at-risk behaviours such as addictions, social history considerations, and pregnancy for females.

For THC medicines specifically, mental health concerns are where THC shouldn’t be prescribed. This includes patients with a family or personal history of psychiatric conditions such as psychosis or, as well as those with a history of suicide attempts or suicidal ideation. Patients who are pregnant and breastfeeding mothers should also not have products containing THC.

Furthermore, children and adolescents under the age of 20-years-old, those who have experienced liver disease or have a history of unstable tachyarrhythmia or coronary disease should also avoid medicinal cannabis products with THC.

What are the recommended doses for cannabis medicine?

For CBD products, adults should ideally start with 10mg twice daily doses before increasing by 30mg twice daily, every week until reaching an effective dose of up to 120 – 150mg twice daily. The majority of adult patients will usually require a dose at between 100mg and 150mg for full therapeutic effect.

For children, this formula changes. Starting with 1mg/kg a day, then increasing by 5mg/kg increments up to a maximum of 25mg/kg daily or until therapeutic effect is reached.

However, when it comes to medicinal cannabis products with THC, the dosing changes dramatically for adult patients and shouldn’t be prescribed at all for children unless by a specialist with experience in this area. We advise to start low, go slow and stay low, as most adverse effects from cannabis are due to the THC component.

We recommend starting at 1 – 2.5mg at night, increasing by 1 – 2.5mg every three to five days, up to a dose of 10mg two to three times daily. The overall recommended maximum daily dose is 30mg.

There’s a lot of nuances involved with prescribing medicinal cannabis products. There are patient-specific considerations for metabolising cannabis products on an individual level, as well as looking into wider potential drug interactions.

As the medicinal cannabis sector continues to develop and grow, it will take some time for prescribers to become more comfortable with prescribing these products. This is an important part of providing natural pain relief and for conditions such as anxiety and sleep problems to Kiwis in a responsible manner.

At Eqalis, we’ve developed in-depth courses for both prescribers and pharmacists who want to learn more about the intricacies of medicinal cannabis. For more information, visit

by Elizabeth Plant, Eqalis Chief Medical Officer