Glossary
THC (Δ⁹-tetrahydrocannabinol)
The principal psychoactive cannabinoid in the cannabis plant.
Δ⁹-Tetrahydrocannabinol (THC) is the cannabinoid primarily responsible for the psychoactive effects of cannabis. In medical use, THC-dominant formulations are considered for specific indications — notably MS spasticity, cancer-related nausea and pain, and some chronic-pain conditions — typically when first-line therapy has been inadequate. THC affects CYP450 enzymes (particularly CYP3A4 and CYP2C9), which is relevant for patients taking warfarin, some antipsychotics, or hormonal contraceptives. In South Africa, THC-containing medicines sit on Schedule 6 and are accessed via Section 21 authorisation under specialist oversight.
Related terms
- CBD (cannabidiol)Non-psychoactive cannabinoid with established use in some seizure disorders and emerging use in anxiety.
- CannabinoidA class of compounds that interact with the endocannabinoid system — includes plant-derived (THC, CBD), synthetic, and endogenous forms.
- Schedule 6Higher-risk prescription medicines; includes THC-dominant cannabis products.
- CYP450Family of liver enzymes that metabolise many drugs, including cannabinoids — source of many clinically relevant interactions.