Study on hold since 2009. Awaiting FDA approval of Sugammdex to complete second arm of study.

This study will be conducted to determine the pharmacodynamics, cardiovascular and biochemical effects of succinylcholine when given during electroconvulsive therapy. (ECT). This is a single center, prospective, study in patients who will be receiving ECT as indicated and prescribed by their psychiatrist. The study will be performed twice on each patient, 48-72 hours apart during consecutively scheduled ECT procedures.

Patients will receive the anesthetic that is traditionally given which includes appropriate doses of succinylcholine. Serum potassium and creatinine phosphokinase (CK) levels will be determined pre and post anesthesia; serum and urine myoglobin will be determined post anesthesia. Vital signs data [i.e., heart rate (arrhythmias) and arterial blood pressure] will be compared pre and post anesthesia. In addition patients will be asked about the presence of muscle pain (myalgia) 1 hour before discharge from the recovery room and the following day post ECT.

Inclusion Criteria:

1. A male or non-pregnant female aged 18 years and older
2. American Society of Anesthesiologists physical status 1, 2, 3
3. Scheduled to undergo electroconvulsive therapy under general anesthesia
4. Have given written informed consent

Exclusion Criteria:

1. Pregnant or nursing
2. Any patient in the study investigators opinion who may not be suitable for research.

Patients undergoing electroconvulsive therapy.