Other contraindications include the administration of hydroxyzine alongside depressants and other compounds which affect the central nervous system; if absolutely necessary, it should only be administered concomitantly in small doses. If administered in small doses with other substances, such as mentioned, then patients should refrain from using dangerous machinery, motor vehicles or any other practice requiring absolute concentration, in accordance with safety law.Studies have also been conducted which show that long-term prescription of hydroxyzine can lead to tardive dyskinesia after years of use, but effects related to dyskinesia have also anecdotally been reported after periods of 7.5 months, such as continual head rolling, lip licking and other forms of athetoid movement. In certain cases, elderly patients previous interactions with phenothiazine derivatives or pre-existing neuroleptic treatment may have contributed to dyskinesia at the administration of hydroxyzine due to hypersensitivity caused by prolonged treatment, and therefore some contraindication is given for short-term administration of hydroxyzine to those with previous phenothiazine use. Side effects
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 hydroxyzine.Central nervous system effects such as hallucinations or confusion have been observed in rare cases, attributed mostly to overdosage.
Hutchinsons triad is named after Sir Jonathan Hutchinson (1828–1913). It is a common pattern of presentation for congenital syphilis, and consists of three phenomena:  interstitial keratitis, malformed teeth (Hutchinson incisors and mulberry molars), and eighth nerve deafness. There may also be a deformity on the nose known as saddle nose deformity. == References ==