Is once a month heart guard the best option in Thailand re heartworm avoidance in my Thai mutt?

Any other options.

Any idea of cost in Thailand. (I am out of country and getting extremely conflicting stories here)

Thanks.

i have used heartguard for my boy for over 4yrs. his first 3 dozes were by injection but they do sting when given also its one less injection.

6tabs size 51-100lbs. heartgard plus [ivermectin/pyrantel] 625bht.

pm.me if you want the supplier.