Pharmacokinetics (PK)
The study of how the body absorbs, distributes, metabolizes, and eliminates a drug. Often summarized as ADME: Absorption, Distribution, Metabolism, Excretion.
In Depth
Cannabinoid pharmacokinetics are complex and highly variable. THC is rapidly absorbed by inhalation (Tmax 3–10 min), slowly and variably absorbed orally (Tmax 60–120 min), and extensively distributed to fatty tissues (Vd ~10 L/kg). THC is metabolized to 11-OH-THC (active) and then to 11-COOH-THC (inactive). Elimination is biphasic: initial rapid distribution phase followed by slow release from fat stores. THC can be detected in urine for weeks in chronic users due to fat storage and slow release.
More in Pharmacology
Endocannabinoid System (ECS)
A lipid-based retrograde neurotransmitter system comprising endogenous cannabinoids (endocannabinoids), their receptors (CB1, CB2), and metabolic enzymes.
CB1 Receptor
Cannabinoid receptor type 1. A G protein-coupled receptor (GPCR) primarily expressed in the central nervous system. The primary target of THC's psychoactive effects.
CB2 Receptor
Cannabinoid receptor type 2. A GPCR primarily expressed in immune tissues and peripheral organs. Less abundant in the CNS than CB1.
Anandamide (AEA)
N-arachidonoylethanolamine. The first endocannabinoid identified. A partial agonist at CB1 and CB2 receptors, named from the Sanskrit word "ananda" meaning bliss.
2-Arachidonoylglycerol (2-AG)
The most abundant endocannabinoid in the brain. A full agonist at both CB1 and CB2 receptors.