In an effort to reduce opioid overdose and adverse events, many states enacted policies limiting dose and duration of opioid prescriptions. This study analyzed the rates of opioid overdose and adverse effects in primary care patients before and after the implementation of prescribing policies in Vermont. While there was no change in opioid overdose rates following implementation, there was a 78% decrease in adverse effects rates, particularly among patients with chronic opioid prescriptions and opioid-naïve patients. Statewide policies limiting dose and duration of opioid prescriptions may have positive results among primary care patients.