Top Ten Things Every Clinician Should Know about E-Cigarettes

Authors:
Elizabeth S. Yett, PharmD, BCACP, CTTS
Kirk E. Evoy, PharmD, BCACP, BC-ADM, CTTS

Reviewers:
Rory O. Kim, PharmD. MACM, BCACP
Kelly Kepley, PharmD
Helen Berlie, BHS, PharmD, BCACP

Introduction

For decades, the proportion of US adults who smoke cigarettes has steadily declined, down from 42.6% in 1965 to 11.6% in 2022.¹ Yet despite abundant research regarding the negative health consequences of smoking tobacco cigarettes and the availability of effective smoking cessation medications, smoking cessation has slowed, with 1 in 9 US adults still smoking cigarettes. Thus, new tools to the smoking cessation armamentarium would be welcomed.

Electronic cigarettes (e-cigarettes; also known as e-cigs, electronic nicotine delivery systems [ENDS], vapes, mods, pods, and vape pens) have surged in popularity since their market introduction in 2007. Some view e-cigarettes as a less harmful alternative to traditional cigarettes and a potential harm reduction strategy.  Indeed, emerging research indicates potential utility in that role. However, others see them as a major risk to the 60+ years of progress toward a tobacco-free society.^2-3

Unfortunately, these products, with unique delivery systems and appealing flavors like Bubblegum and Fruity Cereal, have become particularly popular among adolescents and young adults.⁴ This has resulted in a rise in nicotine use among those aged 13 to 30 years old and concerns that e-cigarettes could be a gateway to a new generation of tobacco cigarette users. For this reason, the US Surgeon General cited e-cigarette use among youth as a significant public health concern and made reducing the use of any nicotine-containing product, including electronic nicotine products, a Healthy People 2030 objective.⁵

Are e-cigarettes a harm reduction tool or causing more harm than good? Here are the top ten things every clinician should know about e-cigarettes.

1. E-cigarettes are NOT created equal.

E-cigarettes have evolved considerably since entering the market, starting with older single-use and disposable versions designed to resemble traditional cigarettes to products with refillable cartridges, tanks, and pods. Here is the anatomy of an e-cigarette:⁶

Item	Purpose
E-liquid (also called vape juice, e-juice)	Contains active substances such as nicotine and/or cannabis, flavorings, and a base such as propylene glycol, polyethylene glycol, or glycerol, which are aerosolized in the e-cigarette device
Pod, cartridge, tank	Holds the e-liquid; can be prefilled or refillable; usually transparent so levels can be viewed
Coil or atomizer	Heating element that converts liquid to aerosol and creates the vapor; user activates by puffing
Battery	May be external and rechargeable; provides enough current to heat the atomizer to 400 degrees Fahrenheit in seconds

There are also modifiable pods (“pod-mods”) that allow users to change the voltage, coils, and wicks. These products typically use nicotine salts rather than the freebase nicotine used in most other e-cigarette products. Nicotine salts have a lower pH than freebase nicotine, which allows higher levels of nicotine to be inhaled and with less irritation to the throat.⁶ Disposable e-cigarettes sold in the U.S. have nearly tripled in nicotine strength, and the e-liquid capacity quadrupled between 2017 and 2022.⁷ The increasing size and strength of e-cigarettes has resulted in newer products with nicotine levels comparable to several cartons of cigarettes.⁷ Differing nicotine concentrations among various products and increased ease of use which allows more frequent use throughout the day (e.g., the ability to quickly take a puff at any time and fewer restrictions around their use in public spaces) leads to higher and more unpredictable nicotine consumption when compared with traditional cigarettes.  For this reason, it is more difficult to quantify daily nicotine consumption compared to counting the number of cigarettes smoked. 

2. Although traditional cigarette use is decreasing, e-cigarette use is increasing, particularly in adolescents and younger adults.

E-cigarettes have been sold in the US for almost twenty years, and e-cigarette use among all adults has been relatively stable over the past five years at approximately 4.5-6% of the US population, or 15 million people.⁴ However, e-cigarette use differs significantly among various age groups. According to the National Health Interview Study, as of 2021, rates of e-cigarette use were much lower in people aged 65 years and older (0.9%) and 50-64 years (2.9%), than young adults aged 18-34 years (10%).⁸

Perhaps most concerning, though, are the trends in e-cigarette use among adolescents. E-cigarette use among high school students surpassed traditional cigarette use for the first time in 2014 and has steadily grown over the past decade.⁹ This growth may have peaked though, as the National Youth Tobacco Survey data revealed that youth e-cigarette use has decreased for the past two years.¹⁰ An estimated 1.63 million (5.9%) middle school and high school students reported past 30-day e-cigarette use in 2024— with nearly 40% reporting frequent use and 26.3% reporting daily use. Approximately half of students who had ever used e-cigarettes reported they continue to use them, indicating that many young persons who try e-cigarettes remain e-cigarette users.¹⁰ Furthermore, people who use e-cigarettes were 3-4 times more likely to begin traditional cigarette use in the future, leading to concerns that e-cigarette use, particularly among teens, may reverse the steady progress in lower US smoking rates.¹¹

3. Clever marketing, vape shops on every corner, and low costs have all contributed to the increased popularity of e-cigarettes.

About 75% of middle and high school students report exposure to marketing or advertising about nicotine and tobacco products — including e-cigarettes.⁴ These products are easy to obtain as e-cigarettes can often be purchased at almost any gas station, many pharmacies, and a growing number of local smoke/vape shops. A recent study found that in one Texas city, 40% of the vape shops were located within 0.5 miles of a middle or high school.¹²

The number of US vape shops has increased by 18% annually since 2018, with annual US sales reaching $9 billion.^13-15  The sharp increase in vape shops has been driven by the greater prevalence of nicotine e-cigarette use; the changing retail landscape post-COVID (when many businesses shifted brick and mortar shops to online sales); and the Farm Bill legislation, which legalized hemp production and sale.¹³ While most of these shops sell nicotine vaping supplies, many now also sell other products such as flavored, non-nicotine containing e-cigarettes, smoking paraphernalia, kratom, and a variety of cannabis-derived products (often including cannabidiol [CBD] and tetrahydrocannabinol [THC]).   E-cigarettes may be sold with or without nicotine.^16-17 This may also be contributing to growing levels of adolescent THC use, as recent research identified that up to 27-40% of US high school students who use nicotine e-cigarettes have also used vapes to consume THC.¹¹

Lastly, e-cigarettes are not subject to the same tax requirements as traditional cigarettes, and e-liquids are (in most states) significantly less expensive to the consumer.^18-19 In 2022, the average price of an e-cigarette device was $14.07, which may represent a larger initial investment versus a pack of traditional cigarettes.²⁰ However, the average price of one mL of e-liquid was approximately $2.45, much lower than the typical price of traditional cigarettes, which cost up to $9.00 per pack or more in some states.²¹

4. Regulations and laws surrounding the use of e-cigarettes have been difficult to enforce and have not reduced e-cigarette use.

A federal law enacted on December 20, 2019, raised the federal minimum legal sales age for all tobacco products, including e-cigarettes, from 18 to 21 years.¹⁹ Yet, secret shopper studies in Texas and California have found these age-based sale restrictions ineffective.^22-23

Moreover, despite concerns from the US Food and Drug Administration (FDA) regarding the safety and public health impact of increased e-cigarette use, many e-cigarettes remain available for sale without undergoing FDA review.²⁴ In 2009, the Tobacco Control Act granted the FDA the authority to regulate tobacco products – but that authority did not include e-cigarettes until 2016, when the FDA declared ENDS as tobacco products. That declaration gave e-cigarette manufacturers two years to prepare premarket applications to stay on the market, which was later delayed until September 2020 following industry requests for more time due to the COVID-19 pandemic.²⁵ The FDA has since been reviewing millions of these applications but has still not completed these reviews, leaving many e-cigarettes still on the market waiting a decision.⁴ Although the FDA has denied permission to market a few e-cigarette products and is ramping up efforts to issue warning letters and fines and limit imports of unauthorized e-cigarette products, enforcement has been slow. To date, the FDA has only officially authorized 34 e-cigarette products and devices.²⁶ Although these are the only e-cigarette products that may be lawfully marketed and sold in the US, thousands remain on the market today.²⁶ An alternative to federal regulation is for state and local authorities to restrict sales. As of March 2023, seven states (MA, NJ, NY, CA, MD, RI, UT) have restricted the sale of flavored e-cigarette products.²⁷

5. Although there are fewer health risks associated with e-cigarettes than traditional cigarettes, they are not risk-free.

In addition to the addiction potential of nicotine-containing e-cigarettes, these products often contain other harmful substances such as formaldehyde, acrolein, and heavy metals. There is evidence for increased coughing, wheezing, and asthma exacerbations, potentially carcinogenic DNA damage, impaired functioning of the lining of blood vessels, a greater likelihood of developing heart failure, and increased airway resistance with the use of these products.²⁸

In adolescence, nicotine is especially harmful to developing brains and affects key brain receptors that make young people more susceptible to addiction and dependence.²⁹ Teens that frequently use e-cigarettes have also been found to have increased urine lead and uranium levels, which have been linked to cognitive impairment, behavioral disturbances, respiratory complications, cancer, and cardiovascular disease.³⁰ However, additional research is still needed on the long-term health effects of e-cigarette use. 

Only 19 states have passed comprehensive smoke-free indoor air laws that include e-cigarettes, leading to a greater prevalence of occupational and social exposure to these vapors.¹⁹ E-cigarettes increase the number of fine particles in a surrounding room, which are capable of reaching deep into the lungs and can increase the risks of bronchitis and shortness of breath, worsen heart and lung disease, and even lead to premature death.^32-33

These products may also pose environmental concerns since they consist of batteries containing heavy metals, plastics, and residues of liquid flavors and nicotine, which can pollute waterways and harm wildlife. There are not currently many options for recycling vapes, though one county in Colorado has implemented a free vape waste disposal program.³⁴ Fortunately, the DEA added vapes and cartridges to the list of materials they accept at prescription drug take-back events; however, this does not include lithium-ion batteries.³⁵

While e-cigarette use can harm the lungs and other bodily systems, they expose a person to fewer toxic chemicals than traditional cigarettes, and are generally considered to be less harmful.³⁶ Thus, for those concerned about the health risks associated with smoking but not yet ready to quit, e-cigarettes may be considered a potential harm-reduction strategy.³⁷ The National Harm Reduction Coalition plans to work with Global Action to End Smoking to develop and implement an education and dissemination campaign, with the aim of reducing the number of people who smoke cigarettes through a joint commitment to harm reduction for smoking.³⁸ However, the authors of a recent meta-analysis sought to compare the health effects of e-cigarette and traditional cigarette use. Their conclusion? The assumption that e-cigarette use provides significant harm reduction may need to be reconsidered.³⁹ In this study, e-cigarette use was associated with a lower risk of asthma, chronic obstructive pulmonary disease, and oral disease versus traditional cigarettes, but not cardiovascular disease, stroke, or metabolic dysfunction. Furthermore, as many as 30% of adults who use e-cigarettes continue to also smoke traditional cigarettes (termed dual use).  People who used both e-cigarettes and traditional cigarettes had a greater risk of cardiovascular, pulmonary, and oral disease than those using traditional cigarettes alone.³⁹

6. Drug interactions are less of a concern with e-cigarettes vs. traditional cigarettes.

Smoking traditional cigarettes can lead to clinically significant drug interactions as a result of the polycyclic aromatic hydrocarbons (PAHs) found in tobacco smoke, which function as potent inducers of several hepatic cytochrome P-450 (CYP) isoenzymes.⁴⁰ The primary CYP enzyme responsible is CYP1A2, which can produce important drug interactions with caffeine (which is almost completely metabolized by CYP1A2) and a number of medications, including clozapine, olanzapine, clopidogrel, and warfarin.^40-41 Conversely, because e-cigarettes do not rely on tobacco combustion or produce PAHs, they do not appear to produce clinically important drug interactions. Therefore, if a patient is taking an interacting drug and switches from traditional cigarette to e-cigarette use, this will remove the drug interaction and reduce CYP1A2 metabolic activity, potentially necessitating a dosage adjustment for the interacting drug.

A recent case report described a patient who was previously stable on clozapine therapy but developed supratherapeutic clozapine concentrations and increased adverse effects after switching from traditional cigarettes to e-cigarettes.⁴² However, when the patient subsequently returned to traditional cigarette use, they developed worsening psychotic symptoms requiring intensified psychiatric care. This case highlights the importance of considering the possible alteration of important drug interactions when a patient switches between traditional cigarettes and e-cigarettes. 

7. E-cigarettes may help people quit smoking traditional cigarettes.

Guidelines recommend the combination of pharmacotherapy and behavioral intervention as the first-line therapy for helping patients quit smoking traditional cigarettes.⁴³ Given that smoking cessation medications are limited to nicotine replacement therapy NRT (gum, lozenge, patch, nasal spray), varenicline, and bupropion, e-cigarettes are potentially another option to help patients quit. Clinical guidelines currently state there is insufficient evidence to recommend e-cigarettes as a cessation tools,⁴³ but more recent data suggests they may be useful. A 2024 Cochrane Review and meta-analysis compiled evidence regarding the efficacy and safety of e-cigarettes for smoking cessation.⁴⁴ The review included 88 studies with 27,235 participants; however, only 10 studies had a low risk of bias. Results of the meta-analysis suggested that nicotine-containing e-cigarettes were more effective in promoting sustained smoking cessation than: non-nicotine e-cigarettes (n=1613; RR 1.46, 95% CI 1.09 to 1.96); behavioral support (n=5024; RR 1.88, 95% CI 1.56-2.25) alone; or NRT (n=2544; relative risk (RR) 1.59, 95% CI 1.29-1.93).  It should be noted that studies including either NRT monotherapy or dual NRT were included and pooled together for this comparison. Another Cochrane Review used component network meta-analyses to compare e-cigarettes to smoking cessation pharmacotherapy, allowing for comparison of treatment options that have not been directly compared in head-to-head trials.⁴⁵ This study found that, compared to controls, e-cigarettes (OR 2.37; 95% CI 1.73-3.24), varenicline (OR 2.33, 95% CI 2.02-2.68), and cytisine (cytisinicline; not currently available in the US; OR 2.21, 95% CI 1.66-2.97) were the most effective treatment options based on 6-month quit rates. When compared to other pharmacologic agents, these three treatment options were more effective than NRT monotherapy and bupropion, but not significantly better than combination NRT. 

8. However, e-cigarettes are addictive, and patients using them to quit traditional cigarettes may be trading one habit for another.

Perhaps the most notable study regarding the efficacy of e-cigarettes for smoking cessation was a 2019 randomized controlled trial of 886 patients comparing e-cigarettes to NRT (any NRT formulation was allowed based on patient preference, including monotherapy or combination NRT therapy).  The study found significantly greater 1-year abstinence rates in the e-cigarette group (18% vs. 9.9%, P<0.001).⁴⁶  However, among those in the e-cigarette group who achieved one-year tobacco abstinence, 80% were still using their e-cigarette at the end of the study, indicating that most patients who successfully quit using e-cigarettes traded one nicotine delivery system for another. Several other studies corroborate the addictive potential of e-cigarettes, with many patients finding e-cigarettes to be equally or more addictive than traditional cigarettes.^47-49

9. Be prepared for a discussion with patients who ask if they should use e-cigarettes to assist with smoking cessation.

For pharmacists and other health professionals providing tobacco cessation services, it is relatively common for patients to inquire about the use of e-cigarettes as a cessation tool. Using shared decision-making and the 5 A’s (ask, advise, address, assist, arrange), we recommend discussing the following with your patients: 

• Recent studies have shown that e-cigarettes could help people quit smoking, and it is generally believed that e-cigarettes are somewhat less harmful than traditional cigarettes.
• E-cigarettes are not currently approved as a smoking cessation aid by FDA, have less robust data to support their safety and effectiveness, and pose their own potential health concerns, which may include increased risk of cancer, cardiovascular, or lung disease.
• E-cigarettes are addictive, and research indicates that many people who quit smoking with the use of e-cigarettes continue using them, trading one harmful habit for another. 
• Clinical guidelines recommend a combination of behavioral therapy and an FDA-approved medication – one that has been robustly studied and is not habit-forming — as the first-line treatment for tobacco cessation. 
• If a patient decides to make the switch from traditional cigarettes to e-cigarettes, it is they should inform healthcare providers to address potential changes in the dosing of certain medications.

10. There are currently no FDA-approved products for quitting e-cigarettes, but ambulatory care practitioners should be prepared to assist with e-cigarette cessation.

While there are some resources available to help healthcare practitioners, there are currently no evidence-based guidelines regarding the use of pharmacotherapy for e-cigarette cessation. Compared to traditional smoking cessation strategies, e-cigarette cessation may also pose unique challenges as they may contain higher nicotine concentrations, lack a natural stopping point (e.g., versus smoking a single cigarette), have fewer restrictions regarding their use in public spaces, and may be quickly and discreetly used to enable continual use throughout the day. Given these differences, it is unclear whether currently available traditional smoking cessation treatment approaches would provide similar efficacy for e-cigarette users. More research is needed to develop tailored, evidence-based recommendations. There is some evidence regarding the effectiveness of varenicline and cytisine for e-cigarette cessation.^50-52 While NRT would presumably help reduce nicotine withdrawal symptoms, NRT use may be less straightforward as an e-cigarette cessation tool because it is more difficult to quantify daily nicotine consumption. Beyond traditional pharmacotherapy, most smoke shops also sell e-liquids with lower nicotine concentrations or no nicotine, which may be used as a scheduled tapering plan. Products like Capnos®, an e-cigarette-like device with no nicotine or smoke, are available to help curtail the manual or oral fixation while a person is trying to quit.⁵³

Practitioners should follow the five steps to quit smoking (and vaping) endorsed by the American Heart Association⁵⁴: 

1. Set quit date
2. Choose a method for quitting (e.g. cold turkey, reducing frequency of e-cigarette use, reducing number of puffs)
3. Talk with healthcare professionals
4. Make a plan for quit date and afterward
5. Quit for good on quit date

Other resources include:

• Tobacco Quit Line, 1-800-QUIT-NOW⁵⁵
• Pivot Breathe, an FDA-approved smartphone application⁵⁶
• This is Quitting, a free and anonymous text messaging program from Truth Initiative   designed to help young people quit vaping⁵⁷
• EX, a collaborative effort with the Mayo Clinic Nicotine Dependence Center to provide both evidence-based quitting approaches and an established online quit community⁵⁸

With the rising popularity of e-cigarettes, particularly among adolescents, it is likely that pharmacists and other practitioners will increasingly encounter patients using e-cigarettes. We can start the conversation by simply asking: “Have you ever used an electronic nicotine product such as a vape or e-cigarette?”. More specific follow-up questions can be asked to assess the amount of nicotine used (based on cartridges or pods/day), as well as if other substances, such as THC or CBD, are used concurrently. During these conversations, it is important to remain informed regarding the potential of e-cigarettes as a harm reduction tool for those who wish to stop traditional cigarettes but to understand the risks associated with e-cigarettes.  There are a variety of tools available to help people quit using e-cigarettes.  The ultimate goal should be to abstain from nicotine use. 

FINAL NOTE:  This program will be available for recertification credit through the American Pharmacists Association (APhA) Board Prep and Recertification Program.  To learn more, visit the APhA Geriatric Board Prep and Recertification website and sign up for the Evidence-Based Practice Series.

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