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Medicinal Cannabis. Safety Information

The following table demonstrates the safety ratio of cannabis. (or = Oral ingestion, sm = Smoking)

 

Substance

Effective Dose (ED50)

Lethal Dose (LD50)

Safety Ratio (LD50/ED50)

Dependence Potential

Cannabis - THC (sm)

15mg

>15g

1000

Low / Moderate

Codeine (or)

40mg

800mg

20

Moderate / High

Morphine (or)

20mg

300mg

15

High

Alcohol Ethanol (or)

33g

330g

10

Moderate

References: Gable, R. S. (2006). Acute toxicity of drugs versus regulatory status. In J. M. Fish (Ed.), Drugs and Society: U.S. Public Policy, pp.149-162, Lanham, MD: Rowman & Littlefield Publishers; Gable, Robert S. Comparison of acute lethal toxicity of commonly abused psychoactive substances. Addiction. 99. 686–696 (2004).

Disclaimer: The information presented here should not be used as a dosage guide. Significant differences exist with respect to a person's physiological and psychological reactions. The dosage indicated is the estimated median quantity for a 70 kg adult human who has not developed tolerance to the substance.

ADVERSE EFFECTS AND POTENTIAL DRUG INTERACTIONS

While cannabinoids are less likely to be associated with severe adverse events than, for example,
opiate medicines, details of adverse events with most cannabinoids are lacking. However, a recent
randomised controlled trial of cannabidiol (CBD) for drug-resistant seizures in Dravet syndrome
showed significant adverse events including sedation, convulsions and gastrointestinal disturbance
in some patients. CBD and THC, being lipid plant extracts, require metabolism before excretion.
Although standard pharmacokinetic and pharmacodynamic studies have not been undertaken, from
the small amount of clinical data available, there are likely to be significant pharmacokinetic interactions,
particularly with drugs that are metabolised by, or either inhibit or induce cytochrome P450 (CYP450) enzymes.

acute toxicity of THC

ACUTE TOXICITY OF THC/CBD

Medicinal cannabis products are regarded as having low acute toxicity. However, concurrent use of other drugs may mask the effects of cannabis and severe toxicity. Thus, adverse cardiovascular effects and death may be under-recognised.

In mammals, the median lethal dose of THC has been estimated to be >800mg/kg. CBD appears to be of very low toxicity. Doses of 1000mg/kg CBD appear to have been tolerated safely in humans.

Most cannabinoid metabolism occurs in the liver and involves the CYP450 pathway. THC accumulates in fatty tissue and is released slowly from this storage site. It is not clear if THC also persists in the brain.

IMPORTANT SAFETY INFORMATION

Before taking medicinal cannabis, tell your doctor and pharmacist about all prescription and over-the-counter medications and supplements you take or plan to take.

Tell your doctor immediately if you become severely ill and have some or all of these symptoms:

  • Develop a rash, hives, swelling or have trouble breathing as these may be the symptoms of an allergic reaction.

  • Experience seizures or convulsions

 

Common immediate effects:

  • loss of inhibition

  • spontaneous laughter

  • quiet and reflective mood

  • affected perception including sound, colour and other sensations

  • confusion - altered thinking and memory

  • possible mild paranoia

  • altered vision

  • reddened/bloodshot eyes

  • relaxation

  • sleepiness

  • reduced coordination and balance

  • increased heart rate

  • low blood pressure

  • increased appetite

 

Indicators that the dose might be too high or formulation is not suitable for you:

  • confusion

  • restlessness

  • excitement

  • hallucinations

  • anxiety or panic

  • detachment from reality

  • decreased reaction time

  • paranoia

 

 

Rare side-effect, often associated with cannabis related allergens:

  • Nasal congestion

  • Runny nose

  • Post-nasal drip

  • Sneezing