Medicinal cannabis preparations and cannabis-based medicines

There are a number of cannabis preparations for medicinal purposes and cannabis-based medicines that have been studied in clinical trials and are available in some countries around the world. These include dried flowers of female plants that can be inhaled or used to produce extracts, the cannabis extract Sativex®, pure THC (delta-9-tetrahydrocannabinol) or dronabinol, CBD (cannabidiol), nabilone (Cesamet®) and Epidiolex®, a CBD-rich cannabis extract.

Dried cannabis flowers of the female plant. There are flowers standardised for their THC and CBD content in some countries, including the Netherlands, Canada and Israel. These herbal products are also known as marijuana. Cannabis flowers are often smoked, ingested with an inhaler (vaporizer), made into extracts or otherwise taken orally (as tea or biscuits).

THC or delta-9-tetrahydrocannabinol or dronabinol is the pharmacologically most important ingredient of the cannabis plant, causing a variety of effects in animals and humans. Pure THC (dronabinol) can be obtained from natural sources (extraction from cannabis plants) or produced synthetically. Chemically, THC belongs to a group of closely related substances known as cannabinoids.

Dronabinol is the INN (International Nonproprietary Name) of the isomer of delta-9-tetrahydrocannabinol found in the cannabis plant, the (-)-trans-isomer. This is the only naturally occurring of the possible four isomers.

CBD or cannabidiol is the main non-psychoactive cannabinoid in cannabis. It can also be extracted from the plant or produced synthetically. It has several medicinally useful properties, including anti-epileptic, anti-inflammatory, neuroprotective, anti-anxiety and anti-psychotic effects. When taken together with THC, it reduces its psychic effects.

Marinol® (Unimed Pharmaceuticals, a subsidiary of Solvay Pharmaceuticals) contains a synthetic version of dronabinol (THC). It is produced as a capsule containing dronabinol in sesame oil. In the USA, it is approved for the treatment of loss of appetite associated with weight loss in patients with AIDS (since 1992) and for the treatment of nausea and vomiting associated with cancer chemotherapy in patients who have not responded adequately to conventional medications (since 1985). The drug is also approved in Canada. The patent for Marinol expired in 2011, opening the way for generic dronabinol preparations, which are now available.

Nabilone (Valeant Pharmaceuticals International) Is a synthetic analogue of THC with a similar spectrum of activity. In Canada, the USA (since 1985, then withdrawn from the market and re-approved in 2006), the UK, Australia and Mexico, nabilone is available as Cesamet®. It is approved for the treatment of nausea and vomiting in cancer chemotherapy patients who do not respond to usual antiemetic drugs.

Sativex® (United States Adopted Name (USAN): Nabiximols) (GW Pharmaceuticals) is a cannabis-based medicine containing delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) in a ratio of about 1 to 1 and is administered as an oromucosal spray (into the mouth). Due to the use of whole extracts, it also contains other cannabinoids and terpenes. Sativex has been approved in Canada as an add-on therapy for spasticity and neuropathic pain in adults with multiple sclerosis and for cancer pain. The drug has also been approved in most European countries for the treatment of spasticity in adult patients with multiple sclerosis. It was first approved in the UK in 2010, followed by Spain, Canada, Czech Republic, Denmark, Germany, Sweden, Austria, Italy, Switzerland, Finland, Norway, Poland, France and others. Each spray contains 2.7 mg THC and 2.5 mg CBD.

Epidiolex® (GW Pharmaceuticals) is a liquid CBD extract, a syrup used primarily to treat children and adolescents with rare forms of epilepsy. It is used in the USA for use in Dravet syndrome and Lennox-Gastaut syndrome.