- 1. Use of sedatives or opioids 2. History of central nervous system diseases, like epilepsy, shaking palsy, or chorea, etc 3. Hyperthyroidism 4. Serious diabetes 5. Hyperkalemia 6. Cardiac surgery 7. Serious ventricular disease or atrioventricular block 8. Liver or renal dysfunction 9. Allergies to amide local anesthetics or fat emulsion