Cannabis - CBM

Question 1

What are the two main pharmacologically active cannabinoids from plant base cannabis?

What explains the different effects seen with plant-based cannabis vs pure or synthetic THC/CBD?

Answer 1

1. tetra-hydro cannabinol (THC), Cannabidiol (CBD)
2. The ‘entourage effect’ - the interaction between cannabinoid and the many non-cannabinoid molecules (e.g. terpenes, flavenoids - responsible for smell, colour etc) in plant based cannabis

Question 2

List 4 psychological side effects of THC?

How does CBD affect the therapeutic window of THC?

Answer 2

Euphoria
Dizziness
Sedation
Confusion

CBD used in conjunction with THC broaden’s it’s therapeutic index

Question 3

List two synthetic cannabinoid products available in Canada. For each, provide:

• the THC and CBD ratio
• a common indication of use
• a downside of the medication

Answer 3

1. Nabilone - pure THC analogue, chemotherapy induced nausea, narrow therapeutic window (no CBD)
2. nabiximols (Sativex) - 1:1 CBD:THC, severe cancer pain, prohibitively expensive

Question 4

LIst 5 routes of administration for cannabis? Which route will you suggest for a patient considering a trial of medical cannabis for symptom management. Which route of administration has the fastest onset?

Answer 4

1. smoking
2. vapourization
3. oral (swallowing, sublingual, buccal, spray)
4. topical
5. rectal

Buccal/sublingual oils are currently the optimal choice .

Onset: smoking>oromucosal>oral (swallowing)
Topical = variable

Question 5

Nabiximols (Sativex) is approved by Health Canada for which three indications?

Answer 5

1. neuropathic pain
2. spasticity from MS
3. Severe cancer pain

Question 6

List 5 common side effects of cannabis.

List one severe side effect that is more common children

Do you get withdrawal symptoms when discontinuing cannabis?

Answer 6

dry mouth
tiredness
dizziness
increased appetite
cardiovascular effects
psychoactive effects
impairment of short term memory
impaired motor coordination
altered judgement
paranoia or psychosis 

respiratory depression from cannabis overdose in children

withdrawal symptoms in heavy recreation use but rare a problem with medical administration

Question 7

List 5 contraindications to medical cannabis use. Is driving contraindicated with use?

Answer 7

• unstable cardiac conditions (e.g. arrhythmias, angina, heart failure) - THC causes vasodilation
• presence of delirium or psychosis (THC)
• family history schizophrenia (THC)
• conditions where depression of immune system is undesirable including concurrent use of immune therapies (CBD at high doses has anti-inflammatory and possible immune suppressant effects)

The ability to drive vehicles or to operate machinery has been shown to be impaired by THC, at least until tolerance is developed. Patients should be advised not to drive if they feel in any way impaired.

Question 8

Which enzyme is primarily involved in metabolizing cannabis? List 1 inducer and 1 inhibitor

Answer 8

cytochrome P450 3A4

inducer: rifampin
inhibitor: ketoconazole

Question 9

You are supporting a family physician who wishes to order medical cannabis for a patient. List 5 pieces of advice you will provide them with.

Answer 9

1. oral transmucosal route is the optimal for most situations
2. When filling out a “medical authoriazation” up to a maximum of 1 g/day in equivalent dried product’ is sufficient
3. Start low go slow
4. Sensitivity to cannabis is variable - start preferably with either an equal amount of THC and CBD (1:1 ratio) or a higher CBD content.
5. There is evidence that use of cannabis based medication can provide symptom relief in a variety of conditions, especially in neuropathic pain and chemotherapy-induced nausea and vomiting.

Question 10

List conditions with substantial or moderate evidence that cannabis is an effective treatment for:

Answer 10

Substantial

• Adult chronic pain treatment
• MS spasticity symptoms
• Chemotherapy-induced nausea and vomiting
• Intractable seizures in Dravet and Lennox-Gastaut syndromes

Moderate
-sleep associated disturbance from chronic pain, MS, fibromyalgia, and OSA

Question 11

What is the suggested starting dose of botanically sourced THC and CBD products?

Answer 11

No more than 2.5mg and titrated per effect.

Question 12

What is the starting dose of nabilone?

Answer 12

0.5 - 1mg per day

Question 13

Why is cannabis contraindicated in unstable cardiac conditions?

Answer 13

possibility of vasodilatation from THC causing hypotension.

Question 14

List two medications that have potentially serious drug interactions with cannabis:

Answer 14

Clobazam

Warfarin