Choose the topical product Advantage II, which starts working through contact. Seresto collars offer slow, continuous release of the active ingredients, to protect pets for up to 8 months! Advantage Multi prescription medication is a monthly topical that combines flea and tick control with a heartworm preventive. Rather than administering two different forms of protection, this one medication is all you need for flea, tick, and heartworm control. It also kills certain intestinal parasites.