Vetoryl starts working within 14 days. Vetoryl capsules are given to dogs and are used to treat Cushing’s disease. This particular medication is to be given to your dog orally and daily. The drug is to be given to your pet dog with food. You do not have to break or split the capsule while feeding it. Administered daily (or as prescribed by your vet), Vetoryl will begin its work within a couple of weeks (14 days).