If you have had only one atrial fibrilation episode and are on coumadin, (warfarin) when can you stop this medication?

Depends. That is a tough question and a matter of opinion. Whether you need Coumadin (warfarin) in the first place depends on the chad score (how many risk factors you have). If the afib was related to a temporary situation, such as surgery, it is more likely that the Coumadin (warfarin) can be stopped. Exactly when, is partly a matter of opinion. The longer you go without recurrence, the more likely it is safe to stop.
Monitor. If no valve or coronary disease, and holter monitor shows no recurrence , then one might use Aspirin & Plavix and stop, coumadin (warfarin). Discuss with the cardiologist.

Related Questions

How effective is warfarin (Coumadin) for managing atrial fibrillation?

Warfarin. Warfarin doesn't manage atrial fibrillation. It is an anticoagulant we give to afib patients to decrease the possibility of their having a clot form and cause an embolus to the brain or other part of the body. Read more...