Beyond the Smoke: Inhalers
They’re discreet, portable, and quick-acting.
Move over vape pens, pipes, and joints. A new way to inhale cannabis is hitting the market, and it looks familiar. Aerosol cannabis inhalers that look identical to the inhalers used to treat asthma are becoming increasingly available and offer a host of benefits. And with a growing audience of cannabis users opting not to smoke, inhalers offer a discreet, portable, and quick-acting solution to treating conditions common to cannabis therapy.
A cannabis inhaler looks just like any other metered-dose inhaler. It consists of three major components: the canister that holds the cannabis distillate, the metering valve that allows a specific quantity of aerosolized cannabis distillate to be dispersed with each “puff” (technically called actuation), and a mouthpiece (technically called an actuator) that allows proper operation of the device and directs the aerosol into the lungs.
The canister is filled with a distillate of cannabis. Distillates are cannabis extracts that have been purified and processed to separate the cannabinoids, such as THC and CBD, from the original plant. To make a distillate, fresh cannabis material is treated with a solvent to create a cannabis extract that is then winterized, decarboxylated, and distilled.
Winterizing is the process of removing impurities such as plant waxes, fats, and chlorophyll by mixing the extract with ethanol and placing it in a very cold environment for 24 to 48 hours. The impurities separate from the rest of the extract, which is run through a filter and the impurities are discarded. After filtering, the ethanol is removed by evaporation.
After winterizing, the extract still isn’t active because the cannabinoids are in their acid form. To remove the acid, the extract is heated in a process called decarboxylation. Because distillates are already decarboxylated, they don’t need to be heated immediately before use. This eliminates the need to use fire or other heating elements common to vape pens and doesn’t irritate the lungs with smoke or heat.
Once decarboxylated, the extract is distilled to produce an oil that is one pure cannabinoid. Each cannabinoid has a unique boiling point and molecular weight that determines the distillation time and temperature. Distillation usually occurs in a vacuum environment where pressure can be tightly controlled and the boiling point can be achieved at a lower temperature to maintain a high level of potency. The final product is a highly refined oil rich in one specific cannabinoid (usually CBD or THC) and containing no terpenes.
Because terpenes are what supply the unique flavor and smell of cannabis strains, distillates are flavorless and odorless. Some inhaler manufacturers are adding back terpenes to provide the flavor and smell to which cannabis users are accustomed. And while terpenes are an integral part of the whole cannabis plant and contribute to the “entourage effect” of inhaling smoke from dried flower, adding back terpenes hasn’t been shown to provide the same medicinal benefits as whole plant consumption.
Benefits of a Cannabis Inhaler
There are several benefits to using a cannabis inhaler. Because they look like a familiar medical device, they’re discreet and portable. And the lack of terpenes means there is no familiar odor when inhaling and exhaling. Most important may be the speed at which they can treat symptoms such as pain, muscle spasms, migraine, and the nausea and vomiting associated with chemotherapy. The bioavailability of aerosolized cannabis distillate is similar to vaping equipment at 80%. Because it’s delivered straight to the lungs and into the bloodstream, there’s no first-pass metabolism and it provides symptom relief within seconds.
Another important benefit, especially for medical use, is the ability to deliver consistent, measured doses. For instance, one manufacturer states that each canister contains 100 “puffs,” and each puff dispenses 6.3 mg of distillate containing 5 mg THC into the lungs. This type of exact dosing may bring cannabis medicine into the mainstream, as a common caveat noted by professionals recommending cannabis is the unknown dose of active materials being delivered through conventional administration methods.
While there aren’t many studies about the effectiveness of aerosolized cannabinoids to treat certain conditions, one of the earliest, from 1973, showed that THC administered by a metered-dose inhaler had a dilating effect on the lungs of patients with bronchial asthma.1 The authors posed the practical question as to whether THC in aerosol would be effective in preventing the onset of bronchospasms in exercise-induced asthma. However, because research into the benefits of cannabis had yet to become mainstream, the question was never studied.
More recently, a trial in Israel showed that inhalation of THC from a metered-dose inhaler at very small amounts (0.5 mg THC) provided significant and extended (150 minute) pain relief without reductions in cognitive function. The authors note that this administration method is particularly important because it can be “evaluated pharmacokinetically and pharmacodynamically by accepted pharmaceutical models.”2
How to Use a Metered-Dose Inhaler
Using a cannabis inhaler is simple for anyone who’s been instructed on how to use an asthma inhaler. For those unfamiliar, a review of the proper steps, including the following, is important to deliver the expected dose to the body:
1. Take off the cap.
2. Hold the inhaler upright and shake for five to 10 seconds.
3. Take a deep breath in and out, away from the inhaler.
4. Hold the inhaler upright and bring it into your mouth.
5. Place the inhaler between your teeth and above your tongue. Seal your lips around the mouthpiece without biting.
6. Start to breathe in slowly.
7. Press down on the inhaler canister one time while continuing to breathe in until you’ve had a full breath.
8. Take the inhaler out of your mouth. Hold your breath for five to 10 seconds.
9. Slowly start to breathe out.
Depending on the inhaler and the symptoms to be treated, individuals may be advised to start with one puff, wait five minutes, and evaluate symptom relief. If necessary, they may need additional puffs to achieve the desired threshold. Because the dose of an inhaler can be tightly controlled, it’s well suited to microdosing, or using small amounts of cannabis to provide symptom relief while avoiding the intoxicating effects of THC that may interfere with daily life. Microdosing is especially appealing to patients who want to treat episodic or acute pain and anxiety because it limits intoxication and offers the ability to use multiple small doses throughout the day.
Microdosing therapy usually starts at 2.5 mg THC per dose. In available inhalers, that’s one-half a puff. Since that’s somewhat difficult to gauge, microdosing patients should be instructed to use one whole puff and wait to see whether the desired symptom relief occurs without intoxication. If 5 mg is too much at one time, patients can be instructed to hold their breath for only three to five seconds and then exhale.
Cleaning is important to keep the canister and actuator from getting clogged, as clogging may affect future doses. After using the inhaler, users should clean the inside of the actuator and the tip of the canister with a cotton swab soaked in isopropyl alcohol and clean the mouthpiece after each use.
Because precise dosing of cannabis is one of the main concerns of physicians reluctant to recommend it, this type of administration may be key to bringing cannabis therapy into mainstream treatment for conditions such as chronic pain. Unfortunately, aerosol inhalers aren’t widely available and can be expensive. Clinicians interested in using inhalers with patients should contact the manufacturers to check availability and encourage increasing distribution.
— Bonnie Johnson, MS, RDN, HCP, is a registered dietitian nutritionist, food industry consultant, speaker, and certified cannabis consultant. She spends much of her volunteer time educating a variety of audiences about the benefits and potential risks of using cannabis to treat chronic pain, anxiety, insomnia, and other ailments. As a consultant, she works with the food and cannabis industries to bring science-based education to health care professionals and category-changing products to market.
1. Williams SJ, Hartley JP, Graham JD. Bronchodilator effect of delta1-tetrahydrocannabinol administered by aerosol of asthmatic patients. Thorax. 1976;31(6):720-723.
2. Almog S, Aharon‐Peretz J, Vulfsons S, et al. The pharmacokinetics, efficacy, and safety of a novel selective‐dose cannabis inhaler in patients with chronic pain: a randomized, double‐blinded, placebo‐controlled trial. Eur J Pain. 2020;24(8):1505-1516.