- addiction-prone individuals
- anaphylaxis, possible; may occur as early as the first dose
- angioedema, possible; may occur as early as the first dose
- chronic pulmonary insufficiency
- concomitant use of alcohol and other central nervous system depressants
- elderly and debilitated patients
- nursing mothers
- severely depressed or suicidal patients
- sleep-related behaviors, complex; possibility of patients performing activities while asleep, with no memory afterwards; includes sleep-driving, making phone calls, and preparing and eating food