After how long post-bariatric surgery can DOAC or VKA be started?

The initiation of direct oral anticoagulants (DOACs) or vitamin K antagonists (VKAs) after bariatric surgery is typically recommended to occur around 4 weeks post-operative. This timing is significant for several reasons, primarily related to the stabilization of the patient’s physiology and the absorption of medications after surgery.

Immediately after bariatric surgery, the gastrointestinal tract undergoes significant changes that can affect medication absorption, making early initiation of these anticoagulants potentially less effective or even unsafe. By waiting approximately 4 weeks, the surgical site generally has improved healing, and the patient is often further along in their recovery process, which contributes to a more stable and predictable absorption of medications. Moreover, 4 weeks post-surgery allows the healthcare provider to ensure that complications (such as leaks or infections) have been adequately monitored and managed.

Starting anticoagulation therapy at this point balances the need to prevent thromboembolic events—given that patients post-surgery are at an increased risk—while minimizing complications related to the recent surgical intervention. After 4 weeks, the benefits of starting DOAC or VKA typically outweigh the risks, making it a well-supported timeframe in current clinical guidelines.