Fig. 9. Perioperative assessment of anticoagulants. Anticoagulant usage is widespread and patients do not always volunteer the information that they are taking these drugs; thus, a thorough history is mandatory. These powerful agents significantly increase subconjunctival, anterior chamber, and suprachoroidal space bleeding associated with incisional glaucoma surgery. An increasingly common problem is the combined use of ASA and vitamin E; together these drugs severely inhibit platelet function preventing formation of the platelet plug. The following guidelines are useful to decrease bleeding associated with prophylactic antithrombotic drug therapy:
DrugMechanismWhen to discontinue before surgery
Aspirininhibits platelet aggregation2 weeks before surgery
Vitamin Einterferes with platelet adhesiveness2 weeks before surgery
Plavixinhibits platelet aggregation2 weeks before surgery
Ticlidinhibits platelet aggregation2 weeks before surgery
Aggrenoxinhibits platelet aggregation2 weeks before surgery
Coumadininhibits coagulation factors3 to 5 days before surgery
Persantineinhibits platelet adhesionnot necessary

Plavix = clopidogrel, Ticlid = Ticlopidine, Aggrenox = ASA and dipyridamole, Coumadin = warfarin, Persantine = dipyridamole.