[Renfield is being seduced by Dracula's brides.]
Renfield: This is wrong. Do you hear me? Wrong. This is...WRONG ME! WRONG ME! WRONG MY BRAINS OUT!
When Dracula goes to grab the cell bars on the window to free Reinfeld, the bars are obviously not metal as they shake and have a slight bend to them.
For the scene in which Jonathan drives a stake into Lucy's heart, Steven Weber's reactions to getting doused in blood are real. For this particular sequence, Mel Brooks did not tell him what was going to happen.