Accurate Education - Marijuana (Cannabis): Inhalation: Smoking vs Vaping

Marijuana (Cannabis):

Inhalation: Smoking vs Vaping

Smoked cannabis refers to direct combustion of the cannabis plant and inhalation of the smoke from combustion. Vaporization is a method of inhaling cannabis vaporized by heat without flame which decreases the number of toxic byproducts produced by combustion.

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Use and Dosing:

Marijuana (Cannabis):

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Definitions and Terminology

Inhalation: Smoking vs Vaping

There are a number of differences between smoking and vaping marijuana (cannabis). Although smoking raw marijuana has the advantage of being less expensive, with further evaluation vaping is generally recommended over smoking.

Smoking flowers by combustion (burning) is associated with greater health risks including chronic bronchitis as opposed to vaping, the preferred method of inhalation. The combustion temperature of cannabis is about 450 degrees F. Additionally, vaping provides a more efficient means of extracting THC and other constituents from the flower. It is estimated that 37% of cannabinoids are burned off with combustion. For example, the bioavailability of cannabis is:

- Smoking: 25-30% bioavailability (Reports vary from 2-56%)
- Vaporization: 30-60% bioavailability

This means that one may access as much as twice as much of a flowers active constituents by vaping rather than smoking.

Sex Differences with Smoking and Vaping

On average for. a given THC dose, whole blood THC and 11- OH-THC Cmax values aare qualitatively higher for females than males for both methods of inhalation. Females also exhibit qualitatively higher THCCOOH Cmax concentrations after vaporized cannabis at both doses. Conversely, males display qualitatively higher average THCCOOH concentrations after inhalation of smoked cannabis, particularly at a 25 mg THC dose.

Smoking

Most common route of administration, but not recommended (joints, bongs, pipes, etc.)
Cannabis combusts (burns) at about 450°F and produces toxic byproducts including: tar, PAH (polycyclic aromatic hydrocarbons, or “tars”), carbon monoxide (CO), nitrosamines and ammonia (NH3).
Chronic smoking is associated with respiratory symptoms (bronchitis, cough, phlegm), but not lung cancer nor COPD (if cannabis only). Bronchitis associated with smoking cannabis resolves after cessation of use. Mixing cannabis with tobacco increases respiratory/cancer risk
With joints, 30–50% of cannabis is lost to ‘side-stream’ smoke. A 2003 analysis of vapor from a vaporizer recovered 89.1% THC and 9.5% smoke toxins; in contrast, cannabis smoke from a pipe recovered 10.8% THC and about 87% smoke toxins.
Cannabis (and tobacco) smoking induce the liver enzyme CYP1A2, and this induction is additive when they are smoked together. This may be significant in a patient taking a medicine metabolized by CYP1A2 such as tizanidine (Zanaflex). In this case it is the smoke itself that is responsible for the induction, not the drugs.

Vaping

Depending on the settings, vaping heats cannabis to 250–450°F (160–230 °C) This reduces carbon monoxide (CO) exposure but does not completely eliminate exposure to PAH (polycyclic aromatic hydrocarbons).
Vaporization produces significantly less other harmful byproducts vs. smoking.
Reduced pulmonary symptoms are reported compared to smoking.
As a rule of thumb, loading 300 mg (0.3 gm) of flower rated at 18% THC would allow for a maximum delivery of up to approximately 50 mg THC, less 30–50% of THC lost to ‘side-stream’ smoke, equating to a THC dose of about 25-30 mg THC.
Oven-style Vaporizers for marijuana flower are available. Vaporizers designed for use with loose marijuana flower have a small “oven” chamber that allows for loading up to 0.3 gms of flower to be vaped. The vaporizer heats the flower up to 360 – 420°F over about 45 seconds until it is ready for inhalation.
One interesting finding reported in a recent study was that vaping was associated with a reduced likelihood of feeling high compared with smoking, although the authors did not distinguish vaping extracts vs dry flower. Of note, pharmacokinetic studies comparing smoking with vaping marijuana flower has demonstrated that vaping is more efficient than smoking and leads to higher blood levels of THC, 11-OH-THC, THCCOOH and THCCOOH-glucuronide concentrations. (it should be noted however, blood and oral fluid cannabinoid concentrations and cognitive/psychomotor performance are only moderately correlated at best, and often not correlated at all with blood levels of these cannabinoids. In fact, as described elsewhere, self-reported drug effects and cognitive/psychomotor impairment often persist for several hours after cannabinoid concentrations in blood and oral fluid fell below very low to undetectable levels. Interestingly, no single cannabinoid measured, either in blood or oral fluid, is universally associated with cannabis-related drug effects, physiological changes and cognitive performance).

There are multiple brands and models available in vape shops and on the internet and may be sold in LA marijuana pharmacies. Popular oven-style vaporizers include Pax and DaVinci brands.

Vaping Temperatures

Vaporizers should provide the option of setting a vape temperature. The reason for this is that different cannabinoids and terpenes vaporize at different temperatures. If the flower is not heated to a temperature sufficient to vaporize the particular constituents in the flower, these constituents won’t be able to be inhaled and their benefits will be lost.

Lower Temperatures

In general, cannabinoids vaporize at temperatures from 315• – 430°F (157• – 220• C) while terpenes vaporize at temperatures from 150• – 390°F (66• – 198°C). While it may be best to set the temperature as low as possible to avoid irritation of the airways, the temperature should be set 10• – 15°F ) above the vaporizing point (VP), or boiling point, of the desired constituent with the highest VP. With each flower listed below, the minimum VP is identified based on the terpene profile (when known).

One can also modify the effects of vaping flower by adjusting the temperature directed at modulating the THC which vaporizes at 315°F. By vaping at, or just above this temperature, less THC will be released allowing for a more subtle effect compared with higher settings which will create a greater burst of vaporized THC.

Higher Temperatures

Some cannabinoids have higher vaporization temperatures, including cannabichromene (CBC – 428°F), cannabinol (CBN – 365°F) and THCV (428°F). Of note, CBD doesn’t have a clear set VP, it is more of a vaporization range from 320-356°F (160-180°C), slightly higher than THC.

Therefore, to be certain to get the benefit of the full complement of cannabinoids and a more rapid vaporization of THC and CBD for the strongest impact, higher vaporizing temperatures should be used (430-450°F).

While vaporization points are meaningful, they are not absolute. The vape chamber of the device may not heat the chamber contents perfectly evenly, creating hot and cold spots in the flower that will affect over-all vaporization. An additional factor is that, to a small degree, these constituents may sublimate off at a lower temperature.

Adjusting Vape Temperatures for Specific Benefits

Depending on the terpene profile of the strain, one can also modify their experience by modulating the terpene vaporization. Consider the following scenarios:

Someone seeking cannabis benefits of pain relief and sleep enhancement purchases a flower with the dominate terpenes β-caryophyllene (excellent for pain) and myrcene (excellent for sleep but also very sedating with daytime use). To avoid daytime sedation while maintaining pain benefits, the vape temperature should be set above the vape temperature of β-caryophyllene (266°F) but below that of myrcene (330°F). Taking into account that THC provides pain benefits but also may be sedating or otherwise impair cognitive function and its vape temperature is 315°F, the vape temperature should be set a little below 315°F to avoid too much THC contribution to sedation or just above 315°F to gain its pain benefit, while keeping below 330°F to avoid the sedation from myrcene.
Someone seeking cannabis benefits of pain relief with stimulation and alertness but wishes to avoid too many THC side effects, purchases a flower with high content of the terpene, pinene (which promotes alertness) and is vaporized at 311°F, but a low potency THC (15% or less) which is also vaporized at 311°F. So keeping the temperature around 315• – 320°F allows for a more subtle THC experience with the addition of the uplifting pinene effects, while at the same time by keeping the temperature below 330°F it will avoid the sedating effects of any sedating terpenes also present such as myrcene since it needs 330°F to vaporize.

The minimum vaporizing temperatures cited with each flower is the temperature at which all significant constitutent cannabinoids and terpenes will vaporize.

See also:

Smoking/Vaping Effect

Smoking/Vaping onset of maximum effect: 5–10 minutes
Smoking/Vaping duration of effect: 2-4 hours
Rapid action, advantage for acute or episodic symptoms (nausea/pain).

Oral Ingestion vs Inhalation

Juicing cannabis or making cannabis teas from plant marijuana do not allow for adequate decarboxylation of THCA and CBDA, the relatively inactive components rhat are found in the raw plant that require heat to be converted to the more active forms, THC and CBD.
Oils, capsules and other oral routes have become increasingly popular due to convenience and accuracy of dosing.
Edibles (brownies/cookies) are often more difficult to dose and lead to accidental ingestions, especially children. There are a growing number of reports of accidental overdosing with edidles leading to extreme side effects including panic attacks, paranoia and psychotic-like symptoms. See: Oral Use (Edibles)
Tinctures and lozenges designed to be held in the mouth or under the tongue to allow for more rapid absorption into the blood through the oral mucosa have intermediate onset between inhaled and oral but have limited research. See: Tinctures
Oral onset of maximum effect: 60-180 minutes
Oral duration: 6-8 hours
Less odor, convenient and discrete, advantageous for chronic disease/ symptoms but titrating dosing is more difficult.

Oromucosal (Sublingual & Buccal)

Oromucosal onset of maximum effect: 15–45 minutes
Oromucosal duration of effect: 6-8 hours

Harm Reduction:

Do not operate dangerous equipment or perform potentially dangerous activities after use
Do not combine with tobacco
Do not use with alcohol, opioids, or sedating drugs
Keep cannabis safely stored under lock and key
The maximum recommended dose is 1 inhalation 4 times per day (approximately 400 mg per day) of dried cannabis containing up to 9% THC.

Driving:

Cannabis users should be advised not to drive for at least:

1. Three to four (3 to 4) hours after smoking
2. Six (6) hours after oral ingestion
3. Eight (8) hours if they experience a subjective “high”

Cautions Associated with Inhalation

Inhaled cannabis should be used with caution in:

Patients who smoke tobacco
Patients who are at increased risk of cardiovascular disease
Patients who have anxiety or mood disorders
Patients who are taking high doses of opioids or benzodiazepines

The principle reason for caution with inhaled drugs is that in general inhaled drugs have more immediate and higher blood levels associated with this means of administration. Therefore, especially in the case of cannabis-based products, there is a greater risk for side effects, especially cognitive dysfunction such as sedation, confusion and impaired decision making and problem solving. Also, with inhaled medications there is greater difficulty in accurately determining dosage unless provided with inhaler devices designed to deliver specific amounts of drug. Additionally, due to the heightened and immediacy of drug-induced effect associated with inhalation, there is an increased risk for abuse and addiction compared with other means of administration such as sublingual, buccal or oral.

Dosing Considerations with Raw Marijuana

See:

Marijuana (Cannabis) – Dosing

Marijuana (Cannabis) – Dosing: “Pot” vs. Pharmaceutical Products

The determination of dosing is one of the major stumbling blocks in the study of medical marijuana. This is because marijuana, a plant, varies widely in the amount and ratios of the pharmacologically active constituents present depending on a multitude of variables. Depending on the plant there may be over 100 pharmacologically active constituents all of which vary depending on the genetics of the plant, the conditions in which the plant was grown, how and when it was harvested and other variables. As such there is a huge variability in the potency and expected effects between different plants.
As noted above, the major pharmacologically active constituents found in marijuana are the cannabinoids THC and cannabidiol (CBD). The average contents of THC and CBD in dried plant preparations of marijuana confiscated from 1993 to 2008 in the United States were 4.5 and 0.4, respectively, although these contents vary widely. In the last decade these percentages have increased in different strains to more than 5-10 times as potent.
In addition to the cannabinoids there are other constituents found in marijuana that may contribute significantly to the pharmacologic effects. Include in these other constituents are the terpenes, fragrant chemicals that often give the notable scents associated with marijuana leaves and flowers. Their pharmacologic roles are currently being studied.
It is also believed there may be an “entourage” effect in which the synergistic actions of the many pharmacologic agents in marijuana contribute to the overall effects, both therapeutic and adverse. Thus it may not be the amount of THC and/or CBD that singularly determine the pharmacologic effects but the overall combination and ratios of the many pharmacologic constituents present in the plants.

The Canadian Experience

In Canada, the medical indications for inhaled marijuana (dried plant) are limited to those patients with severe neuropathic (nerve) pain who have experienced inadequate pain relief or intolerable side effects with trials of standard treatments including: NSAIDs, anticonvulsants (gabapentin (Neurontin) or pregabalin (Lyrica), antidepressants (duloxetine/Cymbalta) and amitriptyline/Elavil, or opioids (tramadol, hydrocodone etc.) and have not responded to adequate trials of pharmaceutical cannabinoids.

Canadian Guidelines Contraindicating Use of Inhaled Cannabis Products:

Inhaled cannabis is contraindicated in:

Patients who are 25 years of age or younger
Patients who have a current, past, or strong family history of psychosis
Patients who have a current or past cannabis use disorder (marijuana addiction)
Patients who have a current substance use disorder (chemical or behavioral)
Patients who have cardiovascular or respiratory disease
Patients who are pregnant or planning to become pregnant

Canadian Dosing Guidelines – Inhaled Cannabis (Smoked and Vaped)

Based on these Canadian guidelines, when smoking is advised (which it is generally not), initial dosing recommendations for smoked marijuana are usually for small amounts of lower-potency marijuana. For example, the starting recommended dosing is 1 inhalation of a “joint” (with up to a 9% THC maximum) once per day. This can be increased to a maximum recommended dose of 1 inhalation 4 times a day, resulting in approximately half a “joint” per day (or up to 400 mg). People should not operate dangerous equipment or perform potentially dangerous activities after use. This includes no driving for a minimum of 3 to 4 hours after inhaled medical marijuana, 6 hours after oral ingestion, and for at least 8 hours if they experience a subjective “high.”

Higher doses are sometimes used. It should be noted that if patients use a 5 gram (current maximum) dose of 15% THC, this represents approximately a 20 times higher dose than the recommended 400 mg of 9% THC. Higher doses, especially at this level are associated with significantly higher risk of adverse side effects (see below). In marijuana resin, which is commonly referred to as hash or hashish, the mean contents of THC, CBD, and CBN are 14.1, 2.5, and 1.9%, respectively. Other commercial products including oils and edibles may contain higher potencies still.

Resources:

National Academy of Sciences

The Health Effects of Cannabis and Cannabinoids: The Current State of Evidence and Recommendations for Research

www.Healer.com

This website appears to be good resource for exploring medical marijuana.

References:

Medical Marijuana – Vaping

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