Hi medical ozstoners, this a long post and not a simple question, but if you want to take time to read it, thanks in advance.
So, in this thread I was hoping to have a discussion about cannabis topicals (creams applied to the skin) edibles and, ahem…suppositories and how they may or may not show up on roadside drug tests used by Australian police (as distinct from smoked cannabis).
A bit of background to explain why I’m interested in this - I’ve never actually used cannabis myself in any form, but a while back I became curious about trying homemade topicals (like a coconut oil infusion) to see if they helped with chronic muscle pain, and as a general relaxant. So I started trying to find out everything I could and pretty soon the issue of drug tests came up. Many people say that topicals with THC aren’t psychoactive and won’t show on drug tests but others say they are or might – there just isn’t any solid research. I started to read anecdotal reports too about roadside drug tests here in Australia, including of how folks have tested positive many, many days after smoking, long after they were actually impaired. I was pretty alarmed by this, as I’m sure are many others, since losing my licence just isn’t an option. To be sure, I’ve had plenty of alcohol breath tests and never once been tested for drugs on the road, but all the same I need to be really, really confident that I would test clean if it did happen. (I’m not worried about urine and blood tests – I just don’t need to take these, but some people might in their workplace).
I wasn’t ready to give up on the idea, and curious besides, so I set about learning what I could about the parameters of saliva drug testing and the police regime here in Australia. In the process of finding out as much as I can about the current road drug testing regime and how it does or doesn’t work (and many of you would know that it is deeply flawed), I’ve found that there is actually very little research about how cannabis that is ingested or applied without being smoked is detected in saliva. Almost all the research and testing relates to cannabis that is smoked (which is after all how most people consume it). The current saliva tests seem to work primarily by detecting remnants of THC that remain in the oral cavity during smoking - and it may be these that can stick around for a long after the effects have worn off, potentially giving a positive result for a sober person. (This isn’t how the roadside tests are supposed to work – they’re supposed to show if you have been smoking very recently and therefore unfit to drive. But they are actually quite sensitive and especially if you are a regular smoker, you could have quite a bit of cannabis chemicals stored in your ‘oral mucosa’)
But…what if you had consumed cannabis extracts in another way, say eating it, swallowing a sealed capsule, rubbing it on your skin or using a suppository? (I presume injecting is a possibility, but I don’t think anyone outside a laboratory actually does that). I’ve tried to find out what I can, and although there is hardly any research it seems that strict blood to saliva transfer of THC may actually be quite low, possibly even undetectable by the current ‘Drugwipe’ tests, overly sensitive as they are. This, I thought, was interesting…
Here’s what I understand currently happens in Victoria and NSW if you get pulled over or stopped at a booze/drug bus. I might be wrong in some details, so please correct me.
The test used first is the Securetec AG Drugwipe which you wipe on your tongue, and it shows a coloured line if positive. (There are different models that test for different numbers of drugs called 6S, 5S and Twinwipe, but with respect to thc they are all the same.) The latest Drugwipe brochure boasts that it can now detect THC in oral fluid at or above 5 nanograms per mL. (Previously the cutoff point was 10 or 12ng). If you do test positive, they then double check your saliva sample in a Draeger 5000 drug test machine – this also has a cutoff point of 5ng/mL I believe.
I actually contacted Securetec AG and asked them about blood to saliva transfer and whether or not THC that was in the blood but hadn’t contacted the oral cavity could be detected by the Drugwipe tests. At first I got an answer to the effect that “if its in your system it’ll get into your saliva”; and then when I asked for more details or any studies that showed this I was basically told that they don’t share data like that with private busybodies. This could mean that its secret in-house research, or as I suspect that they also don’t know.
I tried to read all the published studies I could that were freely available on PubMed. There aren’t many that directly address the question of blood>saliva transfer and some were quite old. I’ve copied out a few salient quotes:
Schramm et al Drugs of Abuse in Saliva: A review Journal of Analytical Toxicology vol 16 Jan/Feb 1992
(20 and 16 are references to papers that I couldn’t get a free copy of, but if you read the original you can see the ref.list)
Radiolabelled ThC administered by intravenous injection cannot be detected in saliva (20). Therefore it seems that THC or its metabolites do not pass into saliva or lungs from the blood but rather are sequestered in the buccal cavity during smoking. In some cases cannabanoids may be detected in saliva for a longer time than in plasma (16) because it is sequestered in the mouth.
Milman et al, Oral Fluid and Plasma Cannabanoid Ratios after around the Clock Controlled Oral Delta 9 Tetrahydrocannabinol Administration, Clinical Chemistry 2011 Nov. 57(11)
In summary, our data demonstrate that THC detected in OF primarily reflects smoked cannabis, not oral administration…
(In this study they took regular smokers and gave them repeated doses of oral THC then measured their saliva and blood levels. They observed that Oral fluid levels were high before they started –possibly because the participants had smoked recently – but as the study went on, the oral fluid levels kept going down, to the point where they were almost zero, even though they still had high levels of THC in their blood.)
Huestis, M. Human Cannabanoid Pharmacokinetics, Chem. Biodivers. 2007 Aug 4(6).
This one is all round interesting and talks about different administration routes and oral fluid testing.
Oral mucosa is exposed to high concentrations of THC during smoking, and serves as the source of THC found in oral fluid. Only minor amounts of drug and metabolites diffuse from the plasma into oral fluid. Following intravenous administration of radiolabeled THC, no radioactivity could be demonstrated in oral fluid. No measurable 11 OH THC or THC-COOH were found by GC/MS (detection limit 0.5 ng/mL) in oral fluid for 7days following cannabis smoking (This suggests to me that these metabolites don’t pass from the blood to the saliva)
(I can’t resist sharing this quote too: Several different suppository formulations were evaluated in monkeys to determine the matrix that maximises bioavailability….That must have been an interesting day at the lab!)
And lastly this study about edibles by the same author was in the news this year. http://www.jhunewsle...tify-marijuana/
I haven’t read it except for the summary on science news sites, but it is actually really relevant. They wanted to find out if edibles, which are becoming more popular in legal MM US states, will show up on roadside saliva tests. They tested the Draeger 5000 and another similar device that had cutoff detection levels of 5ng/mL and 25ng/mL respectively. They took previous smokers (whose mouths may not have been 1000% clean anyway) and gave them each a 50.6mg brownie. As I said I’m not experienced at all but that seems a fairly good dose.
Well, they found that THC could be accurately detected as positive in saliva, but only if the machines were set to a cutoff level much lower, around 1-2ng/mL. This suggests to me that those volunteers could conceivably have driven through an Australian drug test with the Drugwipe/Draeger, and not tested positive, even with fairly high levels in their blood.
I would never advocate driving high or drunk - I want my family to be safe on the roads too, - but what I’m beginning to suspect is that edibles or topicals may be the way to go if you want to responsibly consume, can allow enough time to sober up properly, and hope to test clear at the roadside in following days. Of course if you rub thc oil around in your mouth or eat brownies like the cookie monster you would surely leave residues in your mouth which would show up. I suppose your best bet would be to swallow neatly with a glass of water. (Or make like a lab monkey.)
If only the Drugwipe tests were available cheaply enough for responsible people to test themselves before driving, but unfortunately they run at around $70 each! Even the police pay around $40 per test.
That’s what I’ve got so far – does anyone else have any thoughts, experiences or expertise? Please let me know what you think.