Patients fast for at least 8 hours before and at least 4 hours after and no water is allowed for at least 1 hour before and at least 1 hour after study drug administration. Patients receive a single dose of fentanyl sublingual spray while in an upright position in clinical care recliners or beds, and remain in an upright posture for at least 4 hours after administration. Patients are instructed not to swallow for at least 5 minutes after administration and not to expectorate the drug.