Medical Cannabis Administration Methods
A quick visual reference for patients, carers, and healthcare professionals: how to identify legally prescribed medical cannabis products and their devices, and how quickly each format works in the body.
How quickly each format works, and how long it lasts
Dashed is the wait before you feel anything. Solid is roughly how long the effect lasts. These are typical ranges: your own response depends on your dose, your product and your body.
Absorbed through: the lungs, straight into the bloodstream. A medical vaporiser moves hot air through the flower without setting it alight, which is closer to a nebulised inhaler than to smoking.
Usually chosen for: symptoms that need relief straight away, such as breakthrough pain, a spasm or sudden nausea. Because you feel it quickly, it is also easier to find your own limit.
What it is
Dried cannabis flower prescribed for vaporisation only.
What it looks like
Label includes
What it is
A handheld device used to break medical cannabis flower into small, even pieces for vaporisation.
What it looks like
What it is
A medical device used to inhale vapour from cannabis flower. Never produces smoke and is not considered combustion under smoke-free legislation.
What it looks like
See also: Solowij et al., 2018 (Drugs in R&D) — https://pmc.ncbi.nlm.nih.gov/articles/PMC5833909/
What it is
Liquid cannabis extract taken under the tongue (sublingually) or swallowed.
What it looks like
Label shows
Absorbed through: two routes at once. Part of the dose crosses the lining under the tongue straight into the bloodstream, and the rest is swallowed and absorbed through the gut. Hold it under the tongue for 60 to 90 seconds before swallowing.
Usually chosen for: steady background cover through the day or overnight, often alongside an inhaled format kept for flare ups. Onset is slow and uneven, so waiting the full time your clinic advises matters.
What they are
Pre-dosed edible pastilles containing cannabinoids.
What they look like
Absorbed through: the gut, then the liver before the rest of the body. That first pass turns some delta-9-THC into 11-hydroxy-THC, which is stronger and lasts longer. Food changes how it is absorbed, so clinics often advise taking it the same way each time.
Usually chosen for: overnight cover, and for patients who need a fixed dose with nothing to measure. The same milligrams swallowed can feel stronger than inhaled, and arrive two hours later, so doses should never be stacked while you wait.
What it is
A battery device used with medical cannabis cartridges — not nicotine liquids.
What it looks like
Absorbed through: the lungs, as with flower. Each draw delivers a measured amount of oil, so there is nothing to grind, weigh or pack.
Usually chosen for: fast relief for patients who cannot manage the preparation a flower device needs, or who want something discreet and portable. Prescribed cartridges carry a batch number and a Certificate of Analysis behind them, which illicit cartridges do not.
What it is
A concentrate made from the flower itself, with no solvent used. Hash is made by separating the resin glands from the flower, either dry sieved or washed in ice water, then pressed. Rosin is made by pressing flower or washed hash with heat and pressure so the resin flows out.
What it looks like
How it is taken
In a vaporiser or insert rated for concentrates, usually a small measured amount on a pad or in a dosing capsule. Check your device instructions, because a dry herb chamber is not always suitable. As with flower, combustion is not a prescribed route.
Absorbed through: the lungs, the same route as flower.
Usually chosen for: patients who need a higher dose than flower can comfortably deliver, or fewer inhalations for the same relief. Also chosen by patients who want a product made without any solvent step.
What it is
A pump spray delivering one measured dose at a time to the inside of the cheek or under the tongue. Nabiximols, sold as Sativex, is the example most UK patients meet: a licensed medicine with a fixed one to one ratio of delta-9-THC to CBD.
What it looks like
How it is taken
One spray at a time, directed at the inside of the cheek or under the tongue, alternating sides so the same spot is not used twice in a row.
Absorbed through: the lining of the mouth, so less of the dose has to pass through the gut and liver.
Usually chosen for: conditions where a licensed, standardised product at a fixed ratio is wanted.
What it is
A solid insert used rectally or vaginally, holding a measured dose in a waxy base that melts at body temperature.
What it looks like
How it is taken
Inserted following the instructions from your pharmacy. Nothing is swallowed and nothing is inhaled, which is the point of this route.
Absorbed through: the veins in the lower bowel or the vaginal wall, which largely bypasses the first pass through the liver.
Usually chosen for: times when swallowing or inhaling is not possible, such as severe nausea and vomiting, a gut that is not absorbing, or after surgery. Also used for pelvic pain, including endometriosis, where a local effect is wanted.
