Cornstarch is ok for drying. Caldesene Powder is no longer medicated. Prescription medications may be needed for persistant rashes. Try cloth diapers and presoak them in water, then wash in a mild soap. Rinse the diapers well, perhaps several times.
Some rashes do better in disposable diapers.
Use one diaper medication or routine for at least several days before you decide it is time for a change. If a diaper rash becomes very bad, with bleeding, with spots that are weeping fluid or with blistering, the baby may need a prescription drug to help clear it up. Call the office.