Tush Kush: What You Need to Know About Suppositories
Rectal suppositories could be the very best way to get the most out of your cannabis medicine.
Smoking, vaping, and medibles are the most common methods for patients to get their medicine. Cannabinoids, such as delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) can also be extracted and consumed as an oil or oromucosal spray. The least common method, and perhaps the most intimidating, is via rectal suppository. Yet, for some patients, a rectal suppository could be the most effective way to obtain the appropriate therapeutic dose of THC without the effects of smoking or the need for injections.
Physicians often weigh the pros and cons of each route when considering how to prescribe a medicine. The pharmacokinetics are important; pharmacokinetics describe the mechanism and rate at which the drug enters the blood stream and is taken up by the target tissues; includng how long the concentration of the drug stays at therapeutic levels in the blood stream. Bioavailability of the drug, or what percentage of the drug is actually absorbed into the blood stream as opposed to eliminated from the body, is also considered.
Cannabis, for example, has low bioavailability when consumed orally. The liver will break down some of the active ingredients and dispose of them as waste before they ever have a chance to get into the blood stream. This is often called the “first-pass effect” of the liver. The pharmacokinetics of orally consumed cannabis are also highly variable among individuals and the uptake of active ingredients is relatively slow.
Therefore, prescribing THC or other cannabinoid medicines as an oral dose may not always be the optimal solution. Injections allow more control over the dose and result in much greater bioavailability, but cannot be self-administered. Smoking and oromucosal sprays are easy to self-administer, but some patients may object to smoking and may have difficulty with the sprays. For these patients, a rectal suppository is a good alternative.
One small clinical study (just two patients) found that bioavailability of THC administered in a rectal suppository was twice that of THC taken orally. Studies performed in monkeys found that not only were rectal suppositories superior to oral dosage, but also to injections. The amount of time that the rectally administered THC stayed in the bodies of the monkeys (or mean residence time) was longer by about two and a half hours than when it was intravenously injected. A rectal suppository delivers the drug directly to the blood stream and avoids the first-pass effect of the liver.
However, studies have found that pure THC cannot be absorbed rectally, but it must be administered in a pro-drug form called THC-hemisuccinate. This pro-drug is easily absorbed into the blood stream in the rectum and then is rapidly converted to the THC once in the blood. However, the clinical studies of rectal suppositories are limited to a handful of very small studies, and also the data obtained from monkeys. As a result, cannabis is not often prescribed as a suppository at this time.
For patients who do not wish to smoke cannabis, a rectal suppository is a good alternative to taking cannabinoids orally. A higher therapeutic dose can be administered, and the effects can be felt more quickly than consuming orally. It is also a better option for those patients who have difficulty swallowing or using a spray.