Asthma is a disease of the lungs that consists of 3 clinical aspects: 1) bronchoconstriction, 2) inflammation of the bronchi, and 3) excess mucus production. The disease is usually characterized by a constant state of hyper-reflexivity of the bronchi to allergic components (allergens—usually pollen and/or animal dander). When the patient breaths in these allergens, a cascade of events happens. The allergens bind to allergy cells (mast cells) in the bronchi causes them to release histamine and inflammatory causing agents. Initially, the patient will experience bronchoconstriction followed by inflammation and resulting swelling, excess mucus production, and a further increase in the sensitivity of the lung to any allergen or breathing problem. Repeated exposure to the allergens causes the lungs to be in a consistent state of inflammation and, as a result, persistent problems with asthma symptoms. Medical care of asthma consists of: 1) remedies to reverse the bronchoconstriction (i.e., albuterol, etc.), 2) remedies to prevent and/or treat the inflammation (i.e., inhaled steroids, montelukast, etc), and 3) remedies to decrease the allergic response to the allergens (allergy shots, Xolair, etc). Inhaled steroids are the mainstay for persistent allergy treatment because, as they decrease the inflammation in the lungs, the excess mucus production and airway reactivity decrease and, as a result, the lung’s reaction to allergens decreases, also.
The inflammation of the lungs is caused by the release of inflammatory compounds from the allergy cells in the lung of patients with asthma. CBD lowers the amount of these inflammatory causing compounds in the lungs in asthma and raises the level of specific anti-inflammatory causing compounds. It appears that CBD does not reverse the bronchoconstriction in asthma and should not be used for this purpose. THC, the compound in marijuana that makes people high, does reverse bronchoconstriction somewhat if it smoked or vaped directly into the lung, however, this can actually cause or worsen an asthma attack in some individuals. CBD does not worsen asthma and does not have to be smoked or vaped to decrease the inflammation in the lung. It may be taken orally or under the tongue to have an effect.
In rodent animal models of asthma, systemic administration of cannabidiol decreases the inflammation of the bronchial tubes and decreases mucus production by lowering 4 different interleukins (IL4, -5, -6, and -13) and TNF-alpha, compounds that are elevated in asthma and cause the inflammation.1,2 In addition, cannabidiol did not lower the levels of IL10 which is protective against bronchial inflammation and helps in decreasing the allergic response.2,3 In a guinea pig model of asthma, pulmonary administration of THC but not cannabidiol was found to reverse the bronchoconstriction associated with asthma.4
Similar the the guinea pig model, pulmonary administration of THC and not CBD was found to produce bronchodilatation in humans.5,6 However, the smoking of TCH or its inhalation using a mist produced bronchoconstriction in some cases.7 Using human bronchial epithelial cells, THC has an anti-inflammatory effect that is mediated through CB2 receptors and the bronchodilation effect is through CB1 receptors.8,9
CBD in animals decreases the inflammation associated with asthma and it may also do this in humans via the CB2 receptor pathway. THC seems to be a bronchodilator but only if inhaled via smoking or misting, which causes bronchoconstriction in some individuals. No controlled studies in humans have been performed using hemp oil. However, at this time, neither CBD nor marijuana is recommended for the treatment of asthma by the FDA.
CBD decreases the inflammation associated with asthma in animals and apparently also in humans. THC has some ability as a bronchodilator but only if inhaled via smoking or misting, which causes bronchoconstriction in some individuals. No controlled studies in humans have been performed using hemp oil. However, at this time, neither CBD nor marijuana is recommended for the treatment of asthma by the FDA.
- Jan T, et al (2003). Attenuation of the ovalbumin-induced allergic airway response by cannabinoid treatment in A/J mice. Toxicol Appl Pharmacol. 2003 Apr 1;188(1):24-35.
- Vuolo F, et al (2015). Evaluation of Serum Cytokines Levels and the Role of Cannabidiol Treatment in Animal Model of Asthma. Mediators of Inflamm. 2015 Vol. 2015: Article ID 538670, 5 pages
- Chung F (2001). Anti-inflammatory cytokines in asthma and allergy: interleukin-10, interleukin-12, interferon-gamma. Mediators Inflamm. 2001 Apr; 10(2): 51–59.
- Makwana R, et al (2015). The Effect of Phytocannabinoids on Airway Hyper-Responsiveness, Airway Inflamation, and Cough. Pharm. & Exp. Thera. 2015 Apr; 353:169-180.
- Taskin D, et al (1975). Effects of smoked marijuana in experimentally induces asthma. Am Rev Respir Dis. 1975 Sep;112(3):377-86.
- Gong H, et al. (1984). Acute and subacute bronchial effects of oral cannabinoids. Clin Pharmacol Ther. 1984 Jan;35(1):26-32.
- Taskin D, et al (1977). Bronchial effects of aerosolized delta 9-tetrahydrocannabinol in healthy and asthmatic subjects. Am Rev Respir Dis. 1977 Jan;115(1):57-65.
- Grassin-Delyle S, et al (2014). Cannabinoids inhibit cholinergic contraction in human airways through prejunctional CB1 receptors. British Journal of Pharmacology (2014) 171 2767–2777
- Shang VC, et al (2016). Δ9-Tetrahydrocannabinol reverses TNFα-induced increase in airway epithelial cell permeability through CB2 Biochem Pharmacol. 2016 Nov 15;120:63-71.