Key PointsQuestionWhen and how frequently do patients use manufacturer-sponsored coupons for their prescription drugs during a treatment episode?FindingsIn this cohort analysis of 35 352 individuals receiving pharmaceutical treatment for chronic diseases, nearly all of the first coupon use occurred with the first prescription fills. The frequency of manufacturer drug coupon use was associated with drugs operating in competitive environments but not with patient’s out-of-pocket costs or the characteristics of neighborhoods where the patients reside.MeaningThese findings suggest that manufacturer-sponsored coupons were more likely used to initiate the treatment, and the frequency of coupon use was associated with market competition but not patients’ out-of-pocket costs.