It is ok to use a tick treatment after a flea treatment? I just used a flea treatment without realizing that it wasn't for ticks. My cat goes outside and goes into the wooded area behind our house and I'm constantly picking ticks off of her. Before I run to the store for a tick treatment I want to see if I can combine the two with little to no risk of overdosing her. I put the flea treatment on her two days ago.