Several reactions have been noted in manufacturer guidelines—deep sleep, incoordination, sedation, calmness, and dizziness have been reported in children and adults, as well as others such as hypotension, tinnitus, and headaches. Gastrointestinal effects have also been observed, as well as less serious effects such as dryness of the mouth and constipation caused by the mild antimuscarinic properties of<unk> . Central nervous system problems such as hallucinations or confusion have been observed in rare cases, attributed mostly to overdosage. Such properties have been attributed to<unk>  in several cases, particularly in patients treated for neuropsychological disorders, as well as in cases where overdoses have been observed. While there are reports of the "hallucinogenic" or "hypnotic" properties of<unk> , several clinical data trials have not reported such side effects from the sole consumption of<unk> , but rather, have described its overall calming effect described through the stimulation of areas within the formatio reticularis. The hallucinogenic or hypnotic properties have been described as being an additional effect from overall central nervous system suppression by other CNS agents, such as lithium or ethanol. Somnolence with or without vivid dreams or nightmares may occur in users with antihistamine sensitivities in combination with other CNS depressants.<unk>  exhibits anxiolytic and sedative properties in many psychiatric patients. Other studies have suggested that<unk>  acts as an acute hypnotic, reducing sleep onset latency and increasing sleep duration — also showing that some drowsiness did occur. This was observed more in female patients, who also had greater hypnotic response. The use of sedating drugs alongside<unk>  can cause oversedation and confusion if administered in large amounts—any form of treatment alongside sedatives should be done under supervision of a doctor. Because of potential for more severe side effects, this drug is on the list to avoid in the elderly. In 2015, the European Medicines Agency (EMA) announced a small but definite risk of QT prolongation associated with the use of<unk> . This side effect is more likely to occur in people with pre-existing cardiac disease, or with the use of other medicines known to prolong the QT interval.
Hydroxyzine
Naltrexone
Nabilone
Chloracyzine
Phenelzine
Nortriptyline
Ketanserin
Promethazine