Intermezzo is contraindicated in patients with known hypersensitivity to zolpidem. Observed reactions with zolpidem include anaphylaxis and angioedema.Intermezzo, like other sedative-hypnotic drugs, has central nervous system (CNS) depressant effects. Co-administration with other CNS depressants (e.g., benzodiazepines, opioids, tricyclic antidepressants, alcohol) increases the risk of CNS depression. Intermezzo should not be taken with alcohol. The use of Intermezzo with other sedative-hypnotics (including other zolpidem products) at bedtime or the middle of the night is not recommended. In a driving study, healthy subjects who received Intermezzo with fewer than 4 hours of bedtime remaining had evidence of impaired driving compared to subjects who received placebo. The risk of next-day driving impairment (and psychomotor impairment) is increased if Intermezzo is taken with less than 4 hours of bedtime remaining; if higher than recommended dose is taken; if co-administered with other CNS depressants; or co-administered with other drugs that increase the blood levels of zolpidem. A small negative effect on SDLP (standard deviation of lateral position, a measure of driving impairment) may remain in some patients 4 hours after the 1.75 mg dose in women, and after the 3.5 mg dose in men, such that a potential negative effect on driving cannot be completely excluded. The failure of insomnia to remit after 7 to 10 days of treatment may indicate the presence of a primary psychiatric and/or medical illness that should be evaluated. Cases of angioedema involving the tongue, glottis, or larynx have been reported in patients after taking the first or subsequent doses of zolpidem. Some patients have had additional symptoms such as dyspnea, throat closing, or nausea and vomiting that suggest anaphylaxis. Some patients have required medical therapy in the emergency department. Angioedema and additional symptoms suggesting anaphylaxis may be fatal. Patients who develop angioedema or anaphylaxis should not be rechallenged. Abnormal thinking and behavior changes have been reported to occur in association with the use of sedative-hypnotics, including decreased inhibition, bizarre behavior, agitation, and depersonalization, as well as visual and auditory hallucinations.