Do all illicit drugs harm patients with asthma in the same way? Researchers are still determining the effects that illegal substances have on patients with already compromised airways.
In a literature review of 51 studies of cocaine, heroin, and marijuana, Self and colleagues found that smoking crack cocaine and heroin increased the chances that patients with asthma presented to the emergency department.1 As a result of the dearth of quality evidence, the culled sources included case reports and many retrospective studies.1 Still, the researchers found that 18% to 30% of patients admitted to intensive care units had reported illicit drug use.1
Broaching the Topic of Substance Use
Cannabis was once used an alternative medicine for asthma because of its minor bronchodilator effects.2 Today clinicians need to ask whether their patients with asthma use it in any form.2 It is the most widely used illicit drug globally, and with states’ increasing the legalization of marijuana, some patients may get the erroneous impression that it is completely safe.2
Indeed, cannabis can have serious effects on the central nervous system, including judgment impairment, memory deficits, loss of coordination and attention, and dysphoria, as well as anxiety and psychosis.2 Respiratory-specific symptoms of inhaled marijuana include wheezing, dyspnea, sputum production, tightness in the chest, and acute exacerbations of asthma.2
Although marijuana is a potential allergen, clinicians appear reticent to list it as a potential cause in medical records. Despite the widespread use of marijuana globally (nearly 4% of the world’s population has used it) only 3% of medical records reported marijuana as a causative agent, even in patients who admitted to smoking almost daily.2 Cannabis is used in most countries, but the highest prevalence is in Oceania (10.9%) and North America (10.8%).2
“Experience will vary from individual to individual and with geographical setting. It is something that is a routine question in our urban setting where there is a high level of social deprivation,” noted pulmonologist Paul P. Walker, MD, from Aintree University Hospital in Liverpool, United Kingdom. “If every individual is asked routinely, it becomes a normal question for both the healthcare provider and person being asked.”
One positive aspect of marijuana use: quitting can make respiratory symptoms vanish. Hancox and colleagues discovered in young adults (N=1037) who stopped smoking cannabis that their cough, sputum, and wheeze symptoms were comparable to levels seen in nonusers.3 Participants who frequently used cannabis (≥52 times per year) reported morning cough (odds ratio [OR], 1.97; P <.001), sputum production (OR, 2.31; P <.001), and wheeze (OR, 1.55; P <.001).3
“While it certainly is good medical practice to elicit information from patients attending either primary or specialty care clinics concerning current or previous substance abuse, my impression is that clinicians generally limit their inquiries to tobacco, the most commonly abused smoked substance,” said pulmonologist Donald P. Tashkin, MD, emeritus professor of medicine at the David Geffen School of Medicine at the University of California, Los Angeles.
When clinicians do ask about substance use, they ought to realize that patients who admit to using 1 illegal substance often have tried multiple drugs.4 That point was illustrated in a study of predominantly heroin smokers.4 Lewis-Burke and colleagues sought to characterize the nature of airway disease in 129 heroin users (mean age, 43 years; 70% male) and found that 107 had smoked heroin and the remaining 22 had smoked cigarettes, crack cocaine, or cannabis.4
Overall, 61% of the patients had airway disease.4 The researchers defined asthma as airflow that improved with bronchodilation, airflow obstruction with an forced expiratory volume in 1 second (FEV1) increase of 9% of predicted value with bronchodilation, or an asthma diagnosis before the age of 25 years. Chronic obstructive pulmonary disease (COPD) was defined as a postbronchodilator FEV1/forced vital capacity ratio below the lower limit of normal, and airflow obstruction as a standard residual z-score lower than –1.64.4 A total of 35 of the patients were diagnosed with asthma and 30 had COPD.4
How the Opioid Crisis Exacerbated Asthma
Heroin and opioids present a challenge to clinicians who treat patients with asthma because they induce respiratory depression.5 Insufflation (or snorting) is now the most frequently used method for consuming heroin, which leads to direct damage to the lungs, including bronchoconstriction.5 Cocaine insufflation can also trigger near-fatal status asthmaticus, consuming the drug by smoking provokes bronchoconstriction.5