Inclusion Criteria:  Male or female aged 18 to 55 years inclusive BMI ranging from 18 to 30 kg/m2, inclusive Adequate venous access Subjects must be non-smokers  Exclusion Criteria:  History of clinically significant disease Significant trauma injury, major surgery, open biopsy within 30 days prior to screening Following an abnormal diet 4 weeks prior to screening Use of over the counter medications, dietary supplements, herbal products, vitamins or opioid analgesics 14 days before intervention Use of enzyme altering drugs 30 days before intervention Use of nasal products 28 days before intervention and throughout the study Previous or current opioid, alcohol, or other drug dependence Donated or received blood 30 days before intervention Women who are pregnant or breastfeeding at screening Women of childbearing potential unless surgically sterile or use effective contraception Male subjects of childbearing potential that do not agree to use effective contraception Male subjects who plan to donate sperm or have female partner(s) who are pregnant, lactating or planning to attempt to become pregnant Current or recent upper respiratory tract infection Allergic to nalmefene