Pharmacotherapy is a key component of evidence-based smoking cessation treatment and a major predictor of success in quitting. However, most people attempting to quit in clinical trials fail to fully adhere to their pharmacological treatments.

To assess factors associated with adherence to smoking cessation pharmacotherapies among Black adults participating in a clinical trial and to understand reasons for non-adherence to treatment. Data came from 333 participants enrolled in a randomized clinical trial of adapted therapy (ADT) or enhanced usual care (UC) for smoking cessation. Medication adherence was defined as taking at least 80 % of the prescribed medication for the entire treatment. Characteristics associated with 18-week adherence included demographic, psychosocial, smoking characteristics, substance use, medication experience, early treatment response, and adverse events. A best-subsets regression analyses were performed with all characteristics, and descriptive statistics were used to summarize the reasons for non-adherence to medication.

One hundred seventy-seven participants were compliant with their medication. Participants randomized to the ADT (OR = 2.40, 95 % CI = 1.52–3.81, p < 0.001) and with more positive medication experience (OR = 1.28, 95 % CI = 1.14–1.45, p < 0.001) were more likely to be adherent to study medications. The most common reason for non-adherence was “forgetting or losing the medication” (49.1 %).

Over half of our sample were adherent to their pharmacotherapy, and those randomized to adaptive therapy, coupled with a positive experience with their medication, exhibited better overall compliance with their long-term pharmacotherapy. Reasons for not taking medications were similar to the existing literature.