Generally the following medications are stopped a week before the procedure and resumed a day or two after it:
All of these categories work mainly by inhibiting platelet aggregation and/or fibrin formation — in addition to affecting other steps in the coagulation process — leading to decreased coagulation and blood thinning (which translates into easier bruising). As you can see, There are various items listed above that may not occur to many as possible factors affecting coagulation, and this list is not exhaustive by a long shot. That is why writing down a list of all supplements or herbs you take and having it with you at the clinic is a always good idea.
There are many other blood thinning medications in wide use, but for such minor cosmetic procedures it is unlikely that these need to be stopped, especially if they are taken for health conditions such as a history of a stroke or heart disease. Examples are Warfarin, Heparin, and Pentoxifylline (Trental). Nevertheless, no dermatologist can guarantee zero chance of bruising from a filler or Botox injection, as nicking a small blood vessel is sometimes inevitable, even if your dermatologist is the best there is. In case a bruise does occur, it usually subsides in about a week — tw0 at most. It is worth mentioning that some dermatologists now recommend topical application of Arnica montana, as an anti bruising strategy. Good luck and thank you for reading! Sources: SM. Dinehart, L. Henry. Dietary Supplements: Altered Coagulation and Effects on Bruising. Dermatologic Surgery 2005; 31 (1): 819-26. D. Truong, D. Dressier, M. Hallett. Manual of Botulinum Toxin Therapy. Cambridge University Press 2009 JE. Kim et al. Vitamin E Inhibition on Platelet Pro-coagulant Activity: Involvement of Aminophospholipic translocase Activity. Thrombosis Research 2011; 127 (5): 435-42.