Effects of a Kappa Agonist on Hot Flashes in Menopausal Women

Inclusion Criteria: 1. Healthy women 45-60 years of age; 12 months amenorrhea 2. Documentation of \> 8 moderate to severe, daily hot flashes during one week of baseline monitoring using daily diaries 3. Availability of a family member or friend to drive participant home following clinic visits Exclusion Criteria: 1. Use of hormonal prescription medication or supplements for vasomotor symptoms (VMS) 2. Use of narcotics 3. Use of SSRI (selective serotonin reuptake inhibitor)/SNRI (serotonin-norepinephrine reuptake inhibitors), gabapentin, MAOI (monoamine oxidase inhibitor), anti-epileptics, sedatives 4. History of polycystic ovarian syndrome or hirsutism 5. Current history of depression 6. Any chronic or acute medical illnesses including renal, hepatic, pulmonary diseases, or seizures 7. Substance abuse 8. Severe corn allergy 9. Known allergic reaction to pentazocine or naloxone 10. Presence of a condition or abnormality that in the opinion of the Investigator would compromise the safety of the patient or the quality of the data 11. Hysterectomy 12. Use of anticholinergic medications 13. Lactating or pregnant