Male 55 been on 325 aspirin daily for years for primary prevention. want to reduce to 81 as i understand that is optimal dose. is it safe to do so?

ASA prevention: The amount of ASA needed to inhibit platelet aggregation (clotting) is very small, and a baby ASA is as good as a regular one, and with less chance of GI bleeding. On the other hand, there is still a spectrum of opinion on the optimal dose of ASA, and presumably you are doing well on the 325. Talk to your doctor about this.

Discuss with MD?: I think the key question is -have you had a coronary event? If so I would NOT decrease aspirin. data for PRIMARY prevention is a little less compelling. 81mg would be sufficient to achieve your goals with less risk of ulcer if you are dedicated to doing this without any personal history of event. Note that aspirin may have more compelling preventive effectiveness for colon cancer. Be well