This single-group, small-scale, open-label study (N= 25 to 50) will evaluate the impact of combination zonisamide and bupropion on the process of switching from combustible cigarettes (CC) to an e-cigarette. There will be a data collection period of at least five days to obtain baseline data on use of combustible cigarettes. Participants enrolled in the study will receive a G6 e-cigarette at V2 for ad libitum use. After the first week of e-cigarette use, (at V3) participants will be given zonisamide (100 mg/daily) and will begin extended-release bupropion dosing (150 mg each morning days 1-3, then 300 mg/daily) in addition to continued use of the G6. At each visit, participants will receive enough zonisamide, bupropion, and Halo G6 cartomizers to last until their next study visit. Halo G6 and combination zonisamide and bupropion use will continue until the participant returns for the End-of-Study visit (V7).

Inclusion Criteria:

1. Has signed the ICF and is able to read and understand the information provided in the ICF.
2. Is 21 to 65 years of age (inclusive) at screening.
3. Smokes at least 10 commercially available cigarettes per day (no brand restrictions), for the last 12 months.
4. Has an expired air CO reading of at least 10 ppm at screening.
5. Interested in switching to an electronic cigarette.
6. Willing and able to comply with the requirements of the study.
7. Owns a smart phone with text message and data capabilities compatible with necessary surveys.

Exclusion Criteria:

1. Is unhealthy or cannot participate in the study for any reason (e.g., medical, psychiatric, and/or social reason) as judged by the Investigator or designated medical staff based on all available assessments from the screening period (e.g., safety laboratory, vital signs, physical examination, ECG, concomitant medications and medical history).

2. PHQ-9 score greater than 9, or a score greater than 0 on item #9 ("Thoughts that you would be better off dead, or of hurting yourself in some way") at screening.

3. Planned use of an FDA-approved smoking cessation product during the study.

4. High blood pressure (systolic > 150 mmHg or diastolic >95 mmHg) at screening.

5. Body mass index (BMI) less than 15.0 kg/m2 or greater than 40.0 kg/m2.

6. Coronary heart disease, structural cardiac disease (including, but not limited to valvular heart disease or cardiac murmurs), cardiac dysrhythmias, syncope, cardiac chest pain, or history of heart attack or heart failure.

7. Has received psychotherapy or behavioral treatments potentially impacting symptoms of depression, anxiety, or nicotine withdrawal within 30 days of screening, or during the study.

8. Taking antidepressants, psychoactive medications (e.g. antipsychotics, benzodiazepines, hypnotics) or medications that prolong QTc.

9. Use of any of these products in the past 30 days:

   1. Illegal drugs (or if the urine drug screen is positive for cocaine, THC, amphetamines, methamphetamines, or opiates);
   2. Experimental (investigational) drugs that are unknown to participant;
   3. Chronic opiate use.

10. Use of smokeless tobacco (chewing tobacco, snuff), cigars (except for "Black & Mild" cigars or Cigarillos), pipes, hookah, e-cigarettes, nicotine replacement therapy or other smoking cessation treatments within 14 days of screening.

11. Pregnant or nursing (by self-report) or has a positive pregnancy test.

12. Enrollment requirements met.

Two participants were enrolled into the study but discontinued prior to taken any study drug so analysis is based on the 24 participants who started the study drug.

During 13 week study period.