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Cannabis Dosing and Administration

Patients have different delivery methods for medicinal cannabis

Editor's note: This is the third article in a four-part series that will introduce you to the world of medical cannabis. In the series, we'll cover: the endogenous cannabinoid system; the science behind medical cannabis; the plant's chemical composition, including main components THC and CBD; the different varieties of cannabis and what they're used for; delivery methods, dosing, interactions; and finally, cannabis advocacy and where we are in the fight to legalize medical cannabis in the United States.

In the last two articles, readers were introduced to different terms such as endogenous cannabinoid system, cannabinoids and terpenes. This article will build on those different terms while focusing on the clinical applications of cannabis as a medicine. There are some things worth mentioning around dosing and administration of cannabis first. Cannabis has biphasic effects. In small doses, it can be helpful for things like nausea, appetite, pain, sleep, mood and anxiety. However, in larger doses, cannabis can have the opposite effect leading to an increase in anxiety, pain and/or depression.1

The bidirectional effects of cannabis make it is essential that patients start low and go slow to avoid experiencing any adverse reactions. The most common side effects of Delta-9 tetrahydrocannabinol (THC) are dizziness, dry eyes and mouth, euphoria, increased heart rate, decreased blood pressure, fatigue and increased appetite. Cannabidiol (CBD) can cause psycho-activity, dizziness, jitteriness, diarrhea, palpitations and even decreased appetite with prolonged use.2 With proper guidance, patients can utilize medical cannabis with optimal results and minimal adverse reactions.

Delivery Methods
Today we have many different delivery methods for cannabis. Long gone are the days where the only option was smoking. Now patients can choose from vaporizing, edibles, tinctures, suppositories, topicals and even transdermal patches. There are pros and cons to each delivery method.

Inhalation
The most well-known and popular delivery method is smoking. Smoking cannabis flowers provides relief of symptoms within 5-15 minutes. For many patients with chronic pain, anxiety or acute nausea and vomiting, this delivery method is ideal. The number one concern with smoking cannabis is potential lung damage and/or cancer. Tashkin looked at the possible long term effects on the lungs in chronic cannabis smokers. Taskin found that there was no link to an increased risk of lung cancer or chronic obstructive lung disease. In fact, they found that cannabis may have some protective effects in those who smoke cannabis. 3

When patients smoke cannabis in a joint or pipe, they are heating the medicine at a high temperature close to 600 degrees. At that temperature, burning cannabis is more likely to produce carcinogens and tars. While smoking has not been correlated with any increased risk of lung damage or cancer, it can lead to chronic bronchitis and/or chronic cough.4

SEE ALSO: PTSD and Marijuana

An alternative to smoking is vaporization. There are many different products available for vaping. Some patients vaporize the flowers or buds of the cannabis plant while others prefer to vaporize concentrated cannabis. Some other names of concentrated forms of cannabis are oils, dabs, waxes, shatter, nail hits and rosin. Concentrated forms of cannabis are often extracted with chemical solvents such as butane. Testing for residual solvents is a must to avoid inhaling high levels of residual solvent chemicals. Also, some concentrated forms of cannabis oil have been mixed with propylene glycol to ease inhalation administration.

Inhalation of propylene glycol has been linked to respiratory and immune disorders.5 The concentrated forms are higher potency ranging from 50-90% THC. There is much debate about whether high potency cannabis is truly medicinal or just an attempt for people to get extremely intoxicated. For many patients with neuropathic or cancer related pain, high concentrated cannabis is most effective at relieving their pain.

Inhalation is a quick and easy way to medicate. Contrary to popular belief, inhalation is low dose and easiest to control. Patients can titrate up slowly. While the onset of relief is fast, the length of relief is around 2-3 hours. Inhalation requires more frequent administration and may not be ideal for long lasting relief.  

Ingestibles
Ingestibles can include anything from cookies, brownies, candies, capsules, tinctures, sprays, tea, and oils. The advantage of ingesting cannabis is that it will provide much longer relief than inhalation. In general, patients can experience a reduction in their symptoms for 6-8 hours or more. Most ingestibles in the form of edibles (cookies, brownies, candies, sodas) come in dosages that far exceed the necessary amount to obtain relief. pill box

When cannabinoids are ingested they are processed through the liver. The liver converts delta-9 tetrahydrocannabinol (THC) into 11-hyrdroxy-THC (11-OH-THC) which is a much more potent form of THC. The bio-availability of ingested cannabis ranges from 4-20%.6 Cannabis is fat soluble, delaying full onset of action from 1-3 hours.  These factors make it difficult to dose a majority of THC rich-edibles.  The high variability of ingested cannabis coupled with the delayed onset of effectiveness can lead to potential overmedicating. Often while a patient is waiting for relief, they will consume more than they need, thinking that they didn't take enough originally. Unfortunately, this leads to side effects that can be unpleasant and uncomfortable. In higher dosages of 10 mg or more, patients can experience anxiety, paranoia and/or hallucinations.

Also worth noting is the potential for drug-drug interactions with cannabis.  There hasn't been standards of administration or safety established with CBD and other medications. We know that CBD can either be an inducer or inhibitor of the P450 pathway. More specifically, CBD is metabolized by the CYP3A4, CYP2C9 and CYP2C19. As a result, CBD can either decrease or increase the serum levels of other medications metabolized through these enzymes. THC is also metabolized by CYP3A4 and CYP2C9.7  Levels of THC can be affected by other medications metabolized through these enzymes. More often than not, cannabinoids will increase the effectiveness/toxicity of other medications.Patients must be observed for potential increase in side effects from medications such as blood thinners, anti-depressants and anti-epileptics.

Edibles
Edibles, such as baked goods, lozenges and capsules can be difficult to part out in equal amounts. For example, if a brownie has 100 mg of cannabinoids per package it can be hallenging to break that brownie into several small pieces and expect each piece to be evenly distributed. In a cannabis naïve patient, a recommended starting dose is generally between 2.5-10 mgs of cannabinoid. The more potent the product, the higher chance a patient has of over medicating.

Tinctures, Sprays and Oils
Liquid forms of cannabinoids can be a great way to start low and slow. As long as the products are clearly labeled with dosing, patients can start with as little as one drop or one spray. By definition, a tincture is in an alcohol or glycerin base. Among many cannabis products, tinctures are now being developed in an oil base such as olive oil, coconut oil or medium chain triglycerides (MCT) oil.

Sprays can also be a great way to start low and slow. Many cannabis sprays deliver a metered doses allowing patients to self-titrate.

Topicals and Transdermals
Topical cannabis products can be beneficial for localized issues. Pain, muscle spasms, eczema, psoriasis, bug bites and/or burns can be treated with topical cannabis. The advantage is that the cannabinoids will act locally and not regionally thereby decreasing the potential for systemic side effects. Animal studies have shown that THC topically is two times stronger than hydrocortisone. Topical THC can be effective at reducing itching and inflammation on the surface of the skin. CBD has also been shown to decrease inflammation, muscle tightness and itching. As a topical, CBD absorbs into the skin 10x better than THC.8 When using a topical, patients can expect to experience relief within 20 minutes that can last for several hours.

Transdermal products can come in patches and/or topical gel pens. The transdermal products have been designed to penetrate the skin and reach the blood stream for more system relief. Patches can provide relief within 20 minutes and last for 12 hours. Additionally, if a patch is removed, the adverse reaction will dissipate within 20-30 minutes. It can be a great way to introduce cannabis into a patient who is concerned about negative side effects and allow them some control over dosing and administration. 

Special Considerations
As with all cannabis products, patients should be looking for medicines free of pesticides, solvents, molds, fungus and bacteria. Without standards in place, pesticide use in growing cannabis is unregulated. Solvents, such as butane, hexane and isopropyl alcohol are used to extract concentrated forms of cannabis. Testing the final cannabis product for pesticides, mycotoxins, residual solvents and potency would help ensure the safety of the medicine being consumed.

Finally, cannabis is best when it is individualized to the patient. Dosing is not a one size fits all model and it is not a sliver bullet. Cannabis medicine works best when patients have someone there to guide them and empower them. Nurses are the perfect ones to fill that role.

References
1. National Cancer Institute. (2015). Cannabis and cannabinoids for professionals. Retrieved from http://www.cancer.gov/about-cancer/treatment/cam/hp/cannabis-pdq#section/_3

2. Lee, M. (2014). What is CBD? Retrieved from www.projectcbd.org

3. Tashkin, D.P. (2013). Effects of marijuana smoking on the lung. Annals of the American Thoracic Society, Vol. 10, No. 3 (2013), pp. 239-247.doi: 10.1513/AnnalsATS.201212-127FR

4. Joshi,M, Joshi, A and Bartter, T. (2014) Marijuana and Lung Disease. Current Opinion Pulmonary Medicine.  doi: 10.1097/MCP.0000000000000026.

5. Agency for Toxic Substances and Disease Registry. (2008). Addendum to the toxicological profile of propylene glycol. Retrieved from http://www.atsdr.cdc.gov/toxprofiles/propylene_glycol_addendum.pdf

6. WebMD. (n.d.) Cannabis Pharmacology. Retrieved from http://www.webmd.com/cancer/tc/cannabis-and-cannabinoids-pdq-complementary-and-alternative-medicine---health-professional-information-nci-human--clinical-studies

7. Devitt-Lee, A. (2015). CBD-Drug Interactions:Role of Cytochrome P450. Retrieved from https://www.projectcbd.org/article/cbd-drug-interactions-role-cytochrome-p450

8. Jorge, L.L., Feres, C.C., Teles, V.E. (2011). Topical preparations for pain relief: efficacy and patient adherence. Journal of Pain Resolution. http://dx.doi.org/10.2147%2FJPR.S9492

Eloise Theisen, MSN, RN, AGPCNP-BC, is a certified adult geriatric nurse practitioner who specializes in cannabis therapeutics and has extensive experience in oncology nursing.  In 2014, she started Green Health Consultants (GHC), a clinic dedicated to ensuring patients receive the qualified counseling on cannabis therapeutics.


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