We generally say it is safe to use at any age but for very young (under 12 weeks) puppies and kittens just wet lightly with the diluted solution and towel dry well afterwards.
My vet recommended this product for my pet rats who were suffering from mites. Within a week their sores were healed and they weren’t constantly scratching anymore.
Find your Fido’s retailer
While a store may carry a product type, it’s always best to contact the store directly to confirm that the product you seek is in stock.