I've never needed to use flea/tick treatments *knock on wood* in my 40+ years of owning dogs. However, I know many people in other areas of the country that do, & many of them have concerns about the topical application (drops around the neck/shoulder area), with reactions.
I would suggest talking to your vet, & maybe even sampling at the vet hospitals in your area, to find out what they have found effective. Sometimes, different regions have different 'varieties' of infestation, & what might work well in the south doesn't have as much effect in the north, or different coasts.
On another note - have you discussed treatment with your vet for the anaplasmosis? Standard treatment when presenting with symptoms is an antibiotic (doxycycline) for 4 weeks. There may be some benefit in treating prior to onset of symptoms, to suppress or eliminate the possibility of active infection, but I am not up to date on that literature. A quick Google search only gave me results from 5+ years ago.
Good luck! T. :)