Pharmacists at the University of Waterloo have released a new video with the five basic things people need to know about cannabis, including what it feels like and how long the effects can last.

Professor Michael Beazely said the video was intended to help health professionals and pharmacists understand basics like who should and shouldn't use pot and the healthiest way to consume marijuana, but "in this case, the video works well for everyone."

The video covers five basics of consuming cannabis.

The well-known components are tetrahydrocannabinol (THC) or cannabidiol (CBD). THC makes people feel high and can cause hunger, sleepiness, paranoia and anxiety. CBD doesn't come with a high and is believed to have more medicinal effects. The amounts of THC or CBD can vary in different strains.

There is emerging evidence that cannabis can be used for chronic nerve pain, palliative care, nausea and vomiting from chemotherapy, spasticity from multiple sclerosis and certain drug-resistant seizure disorders in children.

For every hundred people who use cannabis, many will feel high, sleepy or dizzy. Ten to 20 people will have muscle twitching, low blood pressure or feel intensely happy or uneasy. Five to 10 people will experience cannabis use disorder or have memory trouble and up to five will have acute psychosis or dissociation.

Inhaled cannabis starts working in minutes and last around four hours. Edible products start working in an hour or more, lasting around six hours in adults and 12 hours in kids.

Beazley said many people do not understand the period of time before a user feels the drugs' effects, contributing to the number of ER visits caused by eating edibles.

Cannabis should be avoided in pregnancy, breastfeeding and when there is a personal or family history of psychosis. It can double the risk of psychosis in young people, especially if a sibling or parent has a psychiatric disorder such as psychosis.

Finally, Beazely said driving and using heavy machinery should be avoided after consuming cannabis, as it can impair motor function and coordination. It should also be kept out reach of children to prevent accidental poisoning.

"Whenever possible, avoid smoking cannabis. Vaping and edibles are thought to be safer," he said.

The video was produced by his colleague, professor Kelly Grindrod.