 [ Symptoms ] how long does it take for a methylprednisolone injection to take effect i got it 30 hours ago for an ear infection they have an cortisporin ear drop waiting for me at the pharmacy should i pick it up now or give the infection more time to work [ Disease ] what kind of ear infection the only one that may benefit from an injection of a potent steroid would be an inner ear infection dizzy vertigo vomiting etc  cortisporin eardrops will only help otitis externa swimmer is ear since i do not know the reason for the steroid the type or severity of your ear infection ther is really no way to predict when or even if this treatment will work