Hi, and thank you for your question. First and foremost, I would recommend contacting a doctor immediately with this very serious symptom.
Slurred speech can mean a number of things, from drug side effects to a transient ischemic attack (mini-stroke). To get the converstion started with your doctor, I suggest reading the following articles.
Transient Ischemic Attack (TIA)
Plavix Oral
Cardene Oral
Cardizem Oral