Some people have been able to get them from Indian pharmacies. I haven't tried that.
The horse paste is disappearing too. I don't know what people with horses are doing.
Horses don’t have to wormed but every 6 months or so, so they are probably doing ok. I use the injectable (orally) for my goats. There still seems to be plenty of that.
I stocked up early this year.
How many pills in your 3 months supply?