Tetrahydrocannabinol

[+Dizledot]

With some of the discussions revolving around the methods of absorbtion of THC I thought it would be informative to share this. We are experiencing attacks from the anti medical marijuana community on a daily basis. Through our efforts to inform these groups and individules of the falsehoods being spread we need to educate ourselves. Not only does this help educate those groups it will give you some food for thought for the best methods of medicating based upon the condition and rate of absorbtion. Based on the following information the methods whether it be oral (medibles, oils, tinctures) or inhaled (smoked or vaped) the body reacts differently as to the percentage absorbed.

TETRAHYDROCANNABINOL

CASRN: 1972-08-3

 

Absorption, Distribution & Excretion:

Dronabinol is slowly and erratically absorbed from the intestine. The peak plasma concentration is attained in 60 to 90 min, but the latent period may be significantly more prolonged. The systemic bioavailability is 10 to 20%. Dronabinol is 97% to 99% protein bound.

[American Medical Association. AMA Drug Evaluations Annual 1991. Chicago, IL: American Medical Association, 1991., p. 400] **PEER REVIEWED**

 

It is estimated that no more than 60% of delta-9-THC in a marijuana cigarette is actually absorbed. Thus, a 1 g cigarette containing 2% delta-9-THC would deliver at most 10 mg of delta-9-THC to the lungs. ... Plasma concentrations reach their peak at 7 to 10 minutes. ... Although gastrointestinal absorption is largely complete, delta-9-THC is extensively metabolized as it passes through the liver. Bioavailability for delta-9-THC administered orally ranges from 6 to 20%.

[Gilman, A.G., L.S.Goodman, and A. Gilman. (eds.). Goodman and Gilman's The Pharmacological Basis of Therapeutics. 7th ed. New York: Macmillan Publishing Co., Inc., 1985., p. 560] **PEER REVIEWED**

 

Very little unmetabolized delta-9-THC is found in the urine. After reaching their peaks, plasma concentrations of delta-9-THC and 11-hydroxy-delta-9-THC fall rapidly at first (half-time of minutes), reflecting the redistribution of these lipophilic compounds to lipid-rich tissues, including the CNS. This first phase of rapid decline is followed by a much slower phase (half-time of about 30 hours), reflecting the gradual metabolism and elimination of the drug from the body.

[Gilman, A.G., L.S.Goodman, and A. Gilman. (eds.). Goodman and Gilman's The Pharmacological Basis of Therapeutics. 7th ed. New York: Macmillan Publishing Co., Inc., 1985., p. 560] **PEER REVIEWED**

 

Traces of delta-9-THC and its metabolites persist in the plasma of man for several days or weeks.

[Gilman, A.G., L.S.Goodman, and A. Gilman. (eds.). Goodman and Gilman's The Pharmacological Basis of Therapeutics. 7th ed. New York: Macmillan Publishing Co., Inc., 1985., p. 560] **PEER REVIEWED**

 

Clinical studies have reported that heavy cannabis users show positive urinary cannabinoid levels for many weeks after discontinuation from the drug. This prolonged excretion could be explained by accumulation of THC in deep tissue compartments such as fat, followed by return of THC to plasma with subsequent elimination.

[Ellenhorn, M.J., S. Schonwald, G. Ordog, J. Wasserberger. Ellenhorn's Medical Toxicology: Diagnosis and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams and Wilkins, 1997., p. 394] **PEER REVIEWED**

 

The active principles of cannabis are absorbed from the gastro-intestinal tract and the lungs. Emulsified preparations of delta-9-THC have been given by injection.

[Reynolds, J.E.F., Prasad, A.B. (eds.) Martindale-The Extra Pharmacopoeia. 28th ed. London: The Pharmaceutical Press, 1982., p. 354] **PEER REVIEWED**

 

About 50% of the delta-9-THC available in cannabis is present in the smoke inhaled from a whole cannabis cigarette. When cannabis or delta-9-THC is taken by mouth absorption may be slow and irregular.

[Reynolds, J.E.F., Prasad, A.B. (eds.) Martindale-The Extra Pharmacopoeia. 28th ed. London: The Pharmaceutical Press, 1982., p. 354] **PEER REVIEWED**

 

Studies in animals indicated that tetrahydrocannabinol crosses the placenta and is also excreted in breast milk.

[Reynolds, J.E.F., Prasad, A.B. (eds.) Martindale-The Extra Pharmacopoeia. 28th ed. London: The Pharmaceutical Press, 1982., p. 354] **PEER REVIEWED**

 

Drugs such as THC are very lipophilic and distribute into tissues, including the adipose (fatty) tissue, leaving a small amount in the blood. The slow release of THC from the sequestered tissue including adipose tissue into plasma is suggested for the reason for the slow elimination of the drug from the body and therefore the long detection times of previous marijuana use in urinalysis.

[DHHS/NIDA; Research Monograph Series 73: Urine Testing for Drugs of Abuse p.59 (1986) DHHS Pub No. (ADM)87-1481] **PEER REVIEWED**

 

For THC, about 80% of the dose is excreted during the first 5 days following a dose. Approximately 65% of the dose is excreted in the feces and 20% excreted in urine. ... THC /is/ extensively metabolized. The urinary as well as fecally excreted compounds are primarily metabolites with only a minor fraction of unchanged drugs.

[DHHS/NIDA; Research Monograph Series 73: Urine Testing for Drugs of Abuse p.70 (1986) DHHS Pub No. (ADM)87-1481] **PEER REVIEWED**

 

The excretion of a drug into saliva depends on the ability of the drug to pass through the epithelial cells of the salivary glands into the saliva. The concentration of a drug in saliva could be higher, such as amphetamine, or lower, such as methaqualone, than that in plasma. THC or its metabolites are not detecable in saliva following an intravenous dose (Perez-Reyes, personal communications). THC is detectable after smoking marijuana, however, due to the adsorption of THC by the oral mucosa during smoking. Nevertheless, the THC in saliva after smoking is indirectly correlated with recent use of marijuana.

[DHHS/NIDA; Research Monograph Series 73: Urine Testing for Drugs of Abuse p.70 (1986) DHHS Pub No. (ADM)87-1481] **PEER REVIEWED**

 

The mean terminal elimination half-life of THC in plasma (4.3 days) of frequent marijuana users is longer than previously reported (range, 2.6-12.6 days).

[Ellenhorn, M.J., S. Schonwald, G. Ordog, J. Wasserberger. Ellenhorn's Medical Toxicology: Diagnosis and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams and Wilkins, 1997., p. 394] **PEER REVIEWED**

 

After a single usage, only 5-10% of an oral dose of THC is absorbed.

[Gossel, T.A., J.D. Bricker. Principles of Clinical Toxicology. 3rd ed. New York, NY: Raven Press, Ltd., 1994., p. 379] **PEER REVIEWED**