For that type of info you're best bet is to look it up yourself, since I am considerably too squeemish to deal with that sort of subject. These can be found in most pet stores. The best way to do this is to drop some of these pellets in with the crickets several hours before they get fed to the frogs. There are also different types of powders that can be sprinkled on the bugs before you feed them to your frogs. Some specimens are extraordinarily fragile and a lot of the most common problems stem from rough handling or frogs that spaz when you try to handle them, then jump out and smash themselves on something and hurt themselves.
Some frogs even release a fluid as a form of self defense when handled.
This fluid can sometimes be toxic to the person handling the frogs, so be sure to also wash your hands well immediately after any handling as well. In addition, this fluid comes from a reserve supply of body fluid in the frogs, which needs to be replaced as soon as possible. While the best medicine is prevention, here are some common problems encountered by frog-pet owners. See the Prevention notes for Quarantine. I am not a veterinarian.