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Medicinal Cannabis. Administering.

The two main ways to take medical cannabis are (1) Orally ingesting oils and (2) Vaporising dried flower. 

The two methods have different timings for onset and duration of action. Generally, vaporising of dried flowers is used for immediate relief of symptoms and oils are used for a baseline reduction in symptoms. 


When cannabis is inhaled, cannabinoids are absorbed from the lungs into the bloodstream within minutes. In the bloodstream, the cannabinoids are transported to the brain. Maximum concentrations of cannabinoids in the brain are achieved in less than 15 minutes. This time frame correlates with the peak psychological and physiological effects experienced by patients. Effect may vary between individuals based on factors including heating of the cannabis, number of inhalations, wait time between inhalations, the inhalation period and lung capacity.


When consumed orally, cannabinoids are absorbed from the digestive system into the bloodstream. This method of absorption is slower and more unpredictable than inhalation. As such, onset of action can can take 60 to 180 minutes with maximum effect experienced at 2-3 hours

Once in the bloodstream, isoenzymes CYP2C9 and CYP3A4, of the cytochrome P450 system in the liver, convert THC to the biologically active metabolite 11-hydroxy-THC (11-OH-THC). 11-hydroxy-THC is a psychoactive metabolite of THC with sedative effects. This metabolite appears at much lower levels when cannabis is inhaled.

THC and CBD concentrations are higher in the liver after oral administration. 

medicinal cannabis vape


Medical practitioners should note that when administering medical cannabis via inhalation, through a vaporising device, there are currently no vaporising devices included on the ARTG for use with medicinal cannabis.

A vaporising device can be obtained through the unapproved medical device access pathways, which also includes the Special Access Scheme (SAS) pathway.

It should be noted that approval, under the SAS pathway or Authorised Prescriber Scheme, of a medicinal cannabis product requiring inhalation is conditional on use with an appropriate medical device.


Ingesting cannabis oils gives a slower onset of action and longer-lasting effects when compared to inhalation of dried cannabis.

Variance in onset and duration of action is due to several factors including potency and quantity of cannabis oil consumed, tolerance of the user and mechanism of delivery. In addition, there are many patient variables that can influence the effects of ingested cannabis oil such as time of day and empty or full stomach metabolism.

To accurately gauge the effects of cannabis oil, it is recommended to take the same dose under the same conditions every day. It is important to know that dried cannabis and cannabis oils can be used separately or together in achieving a desired outcome.


Smoking of cannabis products is not supported.

It is well-documented that smoking in general is harmful. In addition, when smoked up to 40% of the THC / CBD dose is lost in side stream/combustion, making it difficult to estimate the therapeutic dose an individual patient is receiving.