Pharmacodynamic Evaluation of Intranasal Nalmefene

Inclusion Criteria: * Male or female aged 18 to 55 years inclusive * BMI ranging from 18 to 32 kg/m2, inclusive * Adequate venous access * Healthy subjects and non-dependent who are non dependent opioid experienced users, opioid experience defined as exposure to an opioid on at least 1 occasion prior to screening Exclusion Criteria: * History of clinically significant disease * Significant trauma injury, major surgery, open biopsy within 30 days prior to screening * Subject who has a difficult airway for intubation. * 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 * Current or recent upper respiratory tract infection * Allergic to nalmefene or naloxone or known hypersensitivity reaction to plastics.