The bio-pharmaceutical company Cannabis Science, Inc. has developed two transdermal cannabis patches marketed towards patients with either chronic or neuropathic pain conditions, such as fibromyalgia or diabetic neuropathy.
Developed to be as discreet and unobtrusive as common nicotine patches, the cannabis patches supposedly offer a simple solution to treating topical nerve and muscle pain.
According to Cannabis Science, the patches are designed to be placed on the skin to deliver a specific dose of cannabinoid medications into the bloodstream.
“The medication slowly enters the bloodstream at the chronic pain spot and then penetrates the central nervous system delivering the pain relief reported by self-medicating patients,” explained Dr Allen Herman, Cannabis Science’s chief medical officer in a press release
“An advantage of a transdermal drug delivery route over other types of medication delivery such as oral, topical, intravenous, intramuscular, etc., is that the patch can provide a controlled release of the medication into the patient, usually through a porous membrane covering a reservoir of medication or body heat that melts thin layers of high potency cannabinoid formulations embedded in the adhesive,” the press statement reads.
And while few external reports exist to support the company’s claims, there is good reason to believe cannabis transdermal patches – in theory – could be effective means of cannabinoid delivery.
Foremost, the patches may be able to bypass one of the biggest encumbrances of oral cannabis medications: first-pass metabolism effect, a common phenomenon of drug metabolism whereby the drug’s concentration is greatly reduced before it reaches the body’s systemic circulation.
In the case of cannabis, cannabinoids are often poorly absorbed by the body’s gastrointestinal tract, as Michael Rogers, an associate professor of food science at the University of Guelph, explained to Analytical Cannabis.
“So, depending on the studies we look at, inhalation has the highest bio-accessibility, north of 20-25 percent,” he said.
“But when you start talking about edibles – a chocolate bar, cookie or an oil, for example - you're talking single digit bio-accessibility, meaning 90 percent of that never exerts its biological effects. It's either degraded in first pass metabolism or it's just excreted with the feces.”
However, there are potential disadvantages. Overuse of patches could lead to local irritation and combing the cannabinoids with hydrophilic pharmaceuticals would lead to a low skin penetration.
The patch is not yet commercially available in California, but Cannabis Science has indicated that the products will become available when specific dispensaries partner with the company.
This article was amended on the 8th July 2019 to better reflect the current understanding of transdermal cannabis patches.