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DUI: Cannabis
Terminology and facts about Cannabis relevant to toxicology
Question | Answer |
---|---|
What parts of Cannabis sativa have the highest levels of the primary psychoactive substance? | flowering tops > leaves > stems > seeds > roots |
What are the metabolites of Delta-9-THC? | 11-hydroxy-THC (THC-OH, active metabolite) 11-nor-9-carboxy-THC (THC-COOH, inactive metabolite) |
Describe the metabolism of Delta-9-THC. | Delta-9-THC-->THC-OH-->THC-COOH |
What are the physiological effects of Cannabis? | Red eye, increased heart rate, dry mouth, increased appetite, vasodilation, eyelid tremors, body tremors |
Describe the duration of effects of Cannabis | Peak effects occur at 10-30 minutes. Average duration of euphoria is 2-3 hours. Baseline return is 3-5 hours. Residual effects can last up to 24 hours. |
What is counterclockwise hysteresis? | A delay between effects and plasma concentrations. A drug crosses the blood-brain barrier quickly (fast onset), but it takes about 45 minutes for the drug concentration to reach equilibrium in blood and tissues. |
Describe the cannabinoid receptors. | CB1 and CB2 are G protein coupled receptors. Sense molecule outside cell-->active signal transduction-->cellular response. |
What is the endogenous ligand for the cannabinoid receptors? | anandamide |
What are the half lives of THC and THC-COOH? | THC: 24 hours THC-COOH: 20-57 hours (acute user), 3-13 days (chronic user) |
What is the plasma:whole blood ratio for THC? | 10 ng/mL whole blood = 20 ng/mL plasma |
What are the limitations of the combined model estimation of last consumption? | Postmortem cases due to PMR. Ultra-chronic users. |
What is the Daldrup Intoxication Factor? | Molar ratio: ([THC]+[THC-OH])/[THC-COOH]. The ratio correlates to the feeling of intoxication. |
What is the Cannabis equivalent to the ethanol per se law? | 7-10 ng/mL THC (plasma) produces the same risk of MVA as 0.05 BAC. |
What whole blood concentrations of THC are typically seen at ADFS? | THC: 2.7 ng/mL THC-COOH: 22 ng/mL |
What effects does abstinence have on the residual effects of Cannabis use? | Cannabis abstinence improves divided attention impairment in chronic users. However, after 3 weeks, impairment can still be observed in comparison to control groups. |
What is the main task involved in driving that is affected by Cannabis use? | Vigilance. |
How long can you store samples containing THC? | Can be stored in blood for 3-6 months at -20C. Degrades in heat, light, and air. |
What are the hallmark signs of Cannabis use? | Difficulty following instructions. Short term memory and attention deficits. Issues with vigilance. Time-space distortion. Body and eyelid tremors. Increased reaction time. Psychomotor and cognitive impairment. Motor skill and tracking decrements. |