This was a study published January 20, 2021 by the European Journal of Internal Medicine of elderly patients over a 3 month period. Cannabis-based medicine was administered orally (extract) and by smoking (flower). They used 24-hour monitoring and saw the average daily blood pressure reading drop.
The peak effects occurred 3 hours after administration, and the average reduction in blood pressure was -5.0 mmHg systolic and -4.5 mmHg diastolic.
A summary of the study from NORML with the link to the journal article is here.