Medicinal Cannabis 101 – You Ask. We Answer.

Medicinal Cannabis  101 - You Ask. We Answer.

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Are you considering using medical cannabis for a health problem? I love that you are wanting to try a natural, plant-based alternative!

Read on as I explain some of the science behind medicinal cannabis and its safe use.

What is Medicinal Cannabis?

The terms ‘medicinal cannabis’, ‘medical cannabis’, and ‘medicinal marijuana’ can be used interchangeably. They all refer to the use of cannabis and the compounds (cannabinoids) in the cannabis plant to treat the symptoms of disease and health conditions. This is not to be confused with the use of recreational cannabis which people take to get ‘high’.

Yes, medical cannabis is legal as a prescription-only medication in New Zealand. This means that sourcing it online or from other sources without a script is illegal.

Medicinal cannabis is an unapproved medicine – what does that mean?

Medicines in New Zealand are approved by Medsafe for particular therapeutic purposes. For example, paracetamol is approved to be used for a headache. This is because there has been high quality scientific evidence of paracetamol’s benefit for headaches. However, apart from some rare forms of childhood epilepsy, medicinal cannabis is not an approved medicine for any health condition. This means that it should be used on a case-by-case basis.

Is There THC in Medicinal Cannabis?

Yes, medicinal cannabis can refer to the use of any of the chemical compounds or cannabinoids in the cannabis plant. The two best-known cannabinoids are THC and CBD. Whilst CBD is generally better known for its medicinal benefits, it’s important to remember that THC also has may potential medical benefits.

What are Medicinal Cannabinoids?

As I noted above, any one of the more than one hundred known compounds or cannabinoids in the cannabis plant can be used medicinally to treat a health condition. Each medicinal cannabinoid has a different effect on the body and can be used to treat different symptoms.

What Can Medical Cannabis Possibly be Used For?

Our patients use medical cannabis for a wide variety of purposes. To give you an idea, in a recent poll of 2400 medicinal cannabis users, the main reasons for it’s use were:

  • chronic pain
  • anxiety
  • insomnia
  • joint pain
  • depression
  • muscle tension
  • migraines

Medicinal cannabis has not been proven through research for me to say conclusively if it works or not so therefore, we prescribe it on a person by person basis.

How Does Medical Cannabis Work?

Medicinal cannabis is a plant-based medicine that contains chemicals known as cannabinoids. The human body also has its own cannabinoid chemicals and these are called endocannabinoids. There are many functions of the human endocannabinoid system, including effects on pain, mood, anxiety, and inflammation. The main two endocannabinoids are called: 2-AG and anandamide (there are others also, but these are the most studied). The body also has many receptors in most major organs (including the brain, liver, skin, etc) that respond to these medicinal cannabinoids.  The two main medicinal cannabis receptors are called CB1 and CB2. These receptors were only discovered as recently as 1995! It is thought that medicinal cannabis interacts with these receptors throughout the human body to cause its health benefits.

You can see in the image below all the different areas of the human body where medicinal cannabis interacts via the CB1 and CB2 receptors.

Medicinal Cannabis  101 - You Ask. We Answer.
The cannabinoid system in the body, termed the endocannabinoid system. Reproduced from Terravida.

Is There Any Medicinal Cannabis Evidence?

Is this all hocus-pocus, or is there a real scientific basis to it? Good question! As a doctor, I am naturally biased and all about the science! Here we go:

Short answer: research is not conclusive but there definitely does appear to be a positive benefit when it comes to pain and seizures. More research is needed.

Long answer: Most of the research out there supports the use of medicinal cannabis for seizures and pain. However, because medicinal cannabis is not a pharmaceutical drug, the research currently present is limited in terms of proving a clear benefit from using it. There certainly is research out there, and a lot of it, but conclusive statements need a lot of high-quality evidence. To get technical, there should be some double-blind placebo-controlled trials to prove that medicinal cannabis has therapeutic value. The evidence out there does suggest health benefits, but we can’t say for sure. If you are interested in the nitty-gritty details of what evidence is out there, we suggest you read this study. Given its natural origin and very good safety profile, we have found very promising results from our patients who are using it. There is no doubt in my mind that medicinal cannabis has a role to play in modern medicine.

“When pure and administered carefully, (cannabis) is one of the most valuable medicines we possess”

Sir John Russell Reynold, published in Lancet 1890, Neurologist and personal physician to Queen Elizabeth

How Do I Access Medicinal Cannabis?

Medicinal Cannabis is a prescription-only medication in NZ. This means you need to talk to your GP about having it prescribed. However, chances are that your GP does not know anything about it, and so expect to do some explaining (or let us do the explaining on your behalf). You can also see one of our own experienced cannabis doctors to discuss your health concerns with them if you prefer.

The Cannabis Clinic is here help guide you through this process of talking to your GP and educating them about medicinal cannabis. I have written a free guide to help you navigate this process with your GP. Alternatively, you can make a direct booking with one of our doctors.

In a recent survey of 469 GPs, 89% had no knowledge of the endocannabinoid system.

Is Medicinal Cannabis Safe?

Yes it is very safe. As a matter of fact, there have been no known deaths worldwide from medicinal cannabis exposure.

Medicinal Cannabis Side Effects

Every medicine has potential side effects, but those associated with medicinal cannabis are known to be mild and include:

  • somnolence
  • reduced appetite
  • diarrhoea
  • fatigue
  • asthenia (i.e. weakness)

When used in higher doses (i.e. >10mg/kg/day, so more than 700mg for an average 70kg adult), there is a risk of elevating a liver enzyme called transaminase. This threshold is lower for people using other medications that are metabolised by the liver, such as anti-epileptics. I suggest that people using such doses of medicinal cannabis have liver function testing (LFT) done prior to commencing medicinal cannabis and during treatment. Initially, this should be done after 1 month, 3 months and 6 months of treatment.

Can I get addicted to medicinal cannabis?

You may also be wondering if it is possible to get addicted to medical cannabis? The short answer is no. In a recent report published by the WHO on Medicinal Cannabis, the specialist panel were all in agreement that Medicinal Cannabis is non-addictive and has no potential for abuse if taken in larger quantities. It also cannot be used to manufacture other compounds that have psychoactive or addictive properties.

Medical Cannabis Dosage

This is a difficult to answer precisely because it is not black and white and there are no formal dose recommendations. I usually recommend people start by using a low dose first, 10-20mg per day and gauge the effect after one week. Depending on the result (if any), this dose can then be doubled. This process is repeated until the desired effect takes place. The exact dosage will vary from person to person but I have found good response at the 25 – 50mg once daily range. Some people find quite high doses (e.g. 200 – 300mg daily) are needed to get a benefit.

See below for a helpful guide when in comes to dealing with chronic pain (important to note, this is for CBD and for many people, we prescribe THC alongside the CBD when it comes in trying to improve chronic pain conditins):

Medicinal Cannabis  101 - You Ask. We Answer.


Every person is unique and different. From treating many patients with different health problems, I am quite happy to suggest medicinal cannabis as an option to consider to support various symptoms and I encourage you to also have that discussion with your GP.

If you would like to speak to a professional about using medicinal marijuana in NZ, you can book in with us.

Disclaimer – medicinal cannabis and CBD oil are unapproved medicines in NZ which means that there is no conclusive evidence for their effect, apart from Sativex. Many doctors do not routinely prescribe cannabis medicines. The above article was written for general educational purposes and does not intend to suggest that medicinal cannabis can be used to treat any health condition. Please consult with your healthcare provider. 

MBChB (Otago), BSc (Auckland) - As our tele-medicine doctor and author, Dr. Waseem keeps busy educating both patients and doctors about medicinal cannabis. He also consults with people from all over New Zealand, offering a listening ear and giving the most relevant advice.

14 thoughts on “Medicinal Cannabis 101 – You Ask. We Answer.

  1. Gael Peirce says:

    Thank you for the above information. I have a question, please: can I take Voltaren and medicinal cannabis such as Equalis together?

    • Dr. Waseem Alzaher says:

      Hi Gael, thanks for the question. Yes absolutely you can. Ideally, if on the CBD oil and you get off the voltaren then you would have done your kidneys and stomach and heart good work. Dr Waseem

    • Dr. Waseem Alzaher says:

      Hi Debra thanks for your comment. Medicinal cannabis may help with some symptoms of cancer. If this is what you or a loved one is experiencing, either due to the cancer or the side effect of current treatment, I definitely encourage you to give it a go. Hope this helps!

    • Dr. Waseem Alzaher says:

      Hi Bev, CBD oil overall has not been shown to affect appetite but we have had different experiences from our patients. THC can however stimulate appetite. When used in low therapeutic doses, we aim to minimize side effects as much as possible. Hope this helps!

  2. Sandra Hertnon says:

    Hi I hv fibromylgia Sciatic and last six months at chiropractor with a rare periformus syndrom.iv I had 5months with weekly session s a d one month of fortnightly. I weaned myself off amitriptyline not working for pain as I can’t take anymore than 30mg as it will clash with my venlafaxine. I get to sleep for couple of hrs then wake all night in chronic pain I. Hip leg and lower back. I just recently had traction but it’s a hard muscle to keep fro. Going I to spasm

    • Dr. Waseem Alzaher says:

      Hi Sandra, sorry to hear about what you are going through. It sounds like some CBD + THC may provide some relief and help you sleep better at night time. I encourage you to try it, it does not interact with any of the medications that you are on.

  3. AMY says:

    I suffer from multiple sclerosis and deal with nerve pain and muscle stiffness almost on a daily basis I also suffer from insomnia problems I’m 32 and I feel like I’m living the life of a sore 80 year old woman im worried about going to my doctor to ask about going on cannabis I have been on other pain medications and they just make me feel worse or I have side effects which then they just medicate then I end up on so many medications that I just cant cope .

    • Dr. Waseem Alzaher says:

      Hi Amy, thank you for sharing this and being honest. Really sorry to hear that this is what you are going through. I would love for us to be given the chance to make a difference for you through medicinal cannabis. With MS and cannabis use is where most of the scientific evidence sits, so it is one area where we can say cannabis may really help. I encourage you to give it a try. We are all here to support you. Take care.

  4. Adam Clow says:

    I am into week five recovering from a fracture of my heel .
    I am having to rely on opioids to get sufficient pain relief to be able to sleep.
    In your opinion would medicinal marijuana medication help with my fracture heel pain?

    • Cannabis Clinic says:

      Hi Adam, thanks for reaching out! Medicinal cannabis may be able to help you with the management of your pain and with sleeping too. Depending on how your body reacts to it and the intensity of your pain, you may still need to keep taking your opioid medication alongside it, but you also may be able to cut back or stop it completely.

      We’d recommend booking a consultation with our doctors to see if medicinal cannabis could work for you –

  5. Janice McGill says:

    Hi – my mother has just started Tilray purified CBD @ 0.5ml once daily and would like to know if taking Tilray will negatively interact with other meds she also takes e.g., Mirtazapine and Lorazepam

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