The purpose of this study is to compare and evaluate the safety of AVP-923 (dextromethorphan/quinidine) for the treatment of emotional lability in ALS patients.

Inclusion:

• 18 to 80 years of age, inclusive
• Confirmed diagnosis of ALS or probable ALS
• Clinical history of pseudobulbar affect
• If female, must not be pregnant, breast-feeding, or planning a pregnancy during the course of the study, and must have a negative urine pregnancy test prior to start of study
• If female, must have been practicing an established method of birth control for at least the prior month (oral contraceptive tablets, hormonal implant device, intrauterine device, diaphragm and contraceptive cream or foam, condom with spermicide, tubal ligation, or abstinence) or be surgically sterile or post-menopausal
• Must be willing to not take any prohibited medications during participation in the study

Exclusion:

• Known sensitivity to quinidine or opiate drugs (codeine, etc.)
• On any anti-depressive medication
• Recently (within two months) diagnosed with ALS
• Currently participating in, or who within the past 30 days have participated in, the study of another investigational new drug
• Previously received treatment with co-administration of dextromethorphan and quinidine
• History of substance abuse within the past two years
• Women who are pregnant or likely to become pregnant during the course of the study