What do systematic reviews say?

Hydroxyzine vs Different dosage/timing of hydroxyzine

• Sedation of children undergoing dental treatment 2018 · Cochrane All outcomes
  Any behavioural score - Hydroxyzine: 30 (1 study); VERY LOW. Insufficient evidence to determine whether any specific dose of hydroxyzine is effective.
  1 study · 30 participants
  Very low

Chloral hydrate/hydroxyzine vs A different sedative agent

• Sedation of children undergoing dental treatment 2018 · Cochrane All outcomes
  Any behavioural score - Chloral hydrate/hydroxyzine versus (other sedatives): 235 (6); VERY LOW
  6 studies · 235 participants
  Very low

Chloral hydrate oral (50 mg/kg + 50 mg/kg) vs hydroxyzine hydrochloride oral (1 mg/kg + 1 mg/kg)

Chloral hydrate oral (50 mg/kg + 50 mg/kg) showed no clear difference in number of children with clinical adverse event: behavioural change compared with hydroxyzine hydrochloride oral (1 mg/kg + 1 mg/kg) (low certainty).

• Chloral hydrate as a sedating agent for neurodiagnostic procedures in children 2021 · Cochrane Headline outcomes only
  RR 1.17 [0.4, 3.38]
  1 study · 282 participants
  Low