What are the side effects for Hydromorphone for dog?

Hydromorphone is typically only used in the veterinary clinic due to both its controlled substance status as well as the need to administer it via injection. Side effects can include lowered heart rate and respiratory rate (which may be confounded by the decreased rate due to relief of pain), drooling, panting, whining, lethargy and torpor. Some breeds, such as Greyhounds, tend to be very sensitive to the side effects of hydromorphone, so it is not recommended for use in those breeds.