Still works in my neck of the woods. I put usually combine it with valbazen tho.
It is also what Ive used for my dogs heartworm preventative for the past 10 years.
Haven't used it in years. Stopped when I had a ewe come down with a bad case of barber pole worm. Rolled back her upper eyelid and it was white (should have been pink).
Saved her with a loading dose of Valbazen.