Marijuana half-life

For recreational use, ketamine is often snorted or smoked with marijuana or tobacco products, but it may also be injected intramuscularly (Weiner et al. 2000). The typical street dose of ketamine ranges from 30 to 300 mg. These amounts are in contrast to the chnical doses used for anesthesia, which range from 2 to 10 mg/kg. Ketamine has a half-life of less than 2 hours and is metabohzed by the cytochrome P450 en2yme system (Koesters et al. 2002 Reich and SUvay 1989). 

Uses Paraquat is a colorless, odorless, white or pale yellow crystalline solid that is hygroscopic. Paraquat is a quaternary nitrogen herbicide that is widely used for broadleaf weed control. It is a quick-acting, nonselective compound that destroys green plant tissue on contact and by translocation within the plant. It has been employed for killing marijuana in the United States and Mexico. It also is used as a crop desiccant and defoliant, as well as an aquatic herbicide. Paraquat is highly persistent in the soil environment, with a reported field half-life of greater than 1,000 days.5-7,17... 

Trade names Marihuana Marijuana Indications Nausea and vomiting, substance abuse drug Category Cannabinoid Hallucinogen Half-life N/A... 

After inhalation of marijuana smoke, THC is rapidly absorbed through the lungs and reaches peak blood concentration within minutes thereafter, blood concentration rapidly declines to about 10% of peak levels within 1 to 2 hours. This rapid decline in THC concentration is a result of its facile distribution to tissue such as brain, fat, and muscle. The rapid tissue distribution phase, a consequence of the lipophilic nature of THC, is followed by a slow redistribution of THC back into the blood stream and subsequent hepatic elimination. The terminal elimination half-life of THC is about 1 day in casual marijuana users and 3 to 5 days in chronic users. The peak psychoactive effects of THC generafly lag behind the peak blood concentration by about 20 to 30 minutes. Undoubtedly the concentration of THC in venous blood poorly reflects the THC concentration in the brain. 

Johansson E, Halidin MM (1989) Urinary excretion half-life of delta 1-tetrahydrocannabinol -7-oic acid in heavy marijuana users after smoking. J Anal Toxicol 13 218-223... 

Johansson E, HaUdin MM, AgureU S, HolUster LE, Gillespie HK (1989a) Terminal elimination plasma half-life of delta-l-tetrahydrocannabinol (selta-l-THC) in heavy users of marijuana. Eur J Clin Pharmacol il-.Tl i-lll... 

The authors quote the Determinants of Myocardial Infarction Onset study where of 3883 patients, 124 (3.2%) reported smoking marijuana in the prior year, 37 within 24 h and nine within Ih of MI symptoms to suggest that marijuana may be associated with these patients cardiac issues. Furthermore, in this study, compared to nonusers, marijuana users were more likely to be men, obese and nonsmokers—all these criteria met their patients. The authors postulate that in their patient, sildenafil, by working on the CYP3A enzyme, potentially inhibited the metabolism of marijuana to tetrahydrocannabinoid and thus prolonged the half-life of marijuana resulting in coronary vasospasm. 

Marijuana trafficking is vigorously prosecuted in the United States, with the FBI reporting that nearly half of its 1.5 million drug arrests in 2000 were for marijuana. More than 87% of these arrests were for possession. First-offense convictions for possession of less than 110 lbs (50 kg) of marijuana are punishable by up to five years in prison and fines of up to 250,000 for an individual. Those convicted of possessing more than 2,205 lbs (1,000 kg) of marijuana face up to life in prison and fines of up to 4,000,000. 

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