OBJECTIVES/GOALS: This study explored whether gabapentin (GBN) differentially impacted heart rate variability (HRV) and whether HRV was associated with opioid withdrawal ratings among participants with opioid use disorder (OUD) undergoing a randomized, double blind placebo-controlled, trial (RCT) of GBN during a buprenorphine (BUP)-assisted taper. METHODS/STUDY POPULATION: Participants (ages 18-64) with OUD, no recent use of benzodiazepines/barbiturates, and no major psychiatric disorders or unstable medical conditions were enrolled in the RCT, inducted onto BUP starting week 1 day 1 and randomly assigned to receive adjunct GBN or placebo starting week 1 day 3. All participants began a 10-day BUP-taper beginning week 2 day 3. HRV measures were assessed on week 1 day 2 (before GBN/placebo induction), week 2 day 2, and week 3 day 5 (end of BUP taper). HRV metrics were analyzed using Two Sample T-Test to determine differences between GBN vs. Placebo. Correlations between HRV metrics and opioid withdrawal ratings administered at the above timepoints will be analyzed using Spearman correlation. RESULTS/ANTICIPATED RESULTS: 28 participants underwent at least 1 HRV session that resulted in usable data. Preliminary statistical analyses revealed that HRV trended lower for GBN subjects during PB exercises than Placebo subjects, demonstrated by a higher mean heart rate for GBN subjects compared to Placebo subjects (p=0.0506) at the end of the BUP-taper (week 3 day 5). We expect future analyses to demonstrate a negative correlation between certain HRV metrics indicative of parasympathetic tone and opioid withdrawal rating assessment scores indicative of withdrawal severity. Such findings would demonstrate an association between opioid withdrawal severity and lower parasympathetic tone and HRV. DISCUSSION/SIGNIFICANCE: Individuals with OUD have previously been shown to have a lower parasympathetic tone than individuals without OUD. Additionally, opioid withdrawal has been shown to be associated with reduced parasympathetic tone. Our initial findings suggest that adjunct GBN administration was not associated with lower parasympathetic tone during PB exercises.