How the Body Absorbs Cannabis?

2009.05.05

Marijuana or THC can be taken in various ways:

Smoking leads to fast absorption by the body, with an immediately high plasma concentration. A particular disadvantage in this respect is the inhalation into the lungs of three times more tar than the equivalent in cigarettes.

The results of smoking cannabis are somewhat comparable to those of heavy cigarette smoking. It can lead to lung diseases such as chronic bronchitis, phlegm, shortness of breath and whooping cough, apart from colds, inflammation of the lungs and lung cancer.

Synthetic THC in pill form, from an inhaler or as an oral spray: In order to avoid absorption of medicine by smoking, synthetic THC has been tested in pill form, and from an inhaler or oral spray.

Marinol, a synthetic THC, has been approved in the USA as a prescription drug since 1985, as have Nabilone in the UK and Dronabinol in Germany. The drug can be used to combat the nausea suffered by cancer patients undergoing chemotherapy, and for stimulating the appetite of people suffering from aids. Studies show however that swallowed THC results in widely fluctuating levels of bioavailability, i.e. the amount of substance absorbed by the body cannot be predicted, and varies from person to person.

A plant extract of cannabis has recently become available in the UK as an oral spray sold under the Sativex brand name. The bioavailability of Sativex is more constant than when the drug is delivered in tablet form.

Compared to THC in tablet form, THC in suppository form delivers good bioavailability, constant plasma levels and thus greater effectiveness. Suppositories provide an ideal method of delivery for patients suffering from nausea and vomiting as a result of chemotherapy. However, no such preparation is yet available on the market.

As soon as fat-soluble THC enters the body, it is taken up by fatty tissue for temporary storage. Its half-life period in the body (i.e. the time taken for half of the THC to be eliminated) is approximately one week. A long half-life period of this type makes dosage difficult, and brings with it a danger of accumulations of the substance in the body, resulting in symptoms of toxicity.