Hydroxyzine — Vistaril, Atarax — is a first-generation antihistamine with anxiolytic properties. The mechanism is primarily H1 antagonism, plus 5-HT2A antagonism and alpha-1 effects. The clinical character: rapid onset (~30 minutes), real anxiolytic effect, but heavy sedation and anticholinergic burden.
- Class
- First-generation antihistamine (anxiolytic use)
- Mechanism
- H1 receptor antagonism + 5-HT2A antagonism + alpha-1 antagonism
- Typical dose
- 25-100 mg every 4-6 hours PRN; can use scheduled
- Half-life
- ~20 hours
- FDA indications
- Anxiety, pruritus, allergic reactions, nausea, preoperative sedation
- Key adverse effects
- Sedation (prominent), anticholinergic effects (dry mouth, constipation, blurred vision), cognitive impairment (especially elderly), QTc prolongation at high doses
Useful for: acute anxiety when controlled substance avoided, patients with substance use history, short-term use. Sedation is dominant — not for daytime when alertness needed. Avoid in elderly (anticholinergic burden, fall risk).
Hydroxyzine occupies a specific clinical niche — the patient who needs rapid anxiolytic effect without a controlled substance. The patient with active substance use disorder. The pregnant patient where BZDs are problematic. The patient with a history of BZD misuse where the prescriber prefers to avoid controlled substances. The acutely anxious patient who needs help today but for whom long-term BZD prescribing is inappropriate.
Hydroxyzine is an antihistamine repurposed as an anxiolytic — its sedating H1 blockade provides as-needed anxiety relief without dependence.
Mechanism note: Hydroxyzine offers as-needed, non-addictive anxiety relief — a real benzodiazepine alternative for situational anxiety — limited mainly by anticholinergic burden and QTc concern.
The sedation is the dominant clinical feature. At doses of 25-50 mg, most patients are noticeably sedated. For evening or as-needed use, this is often acceptable; for daytime use when alertness matters, it's a limitation. Hydroxyzine is rarely the right choice when the patient needs to drive, work, or stay alert after the dose.
Anticholinergic burden is substantial. Dry mouth, constipation, blurred vision, urinary retention, cognitive impairment in the elderly. The Beers Criteria list hydroxyzine as potentially inappropriate in older adults for these reasons. For a young patient with intact cognition, the anticholinergic effects are bothersome but tolerable; for an elderly patient, they can be incapacitating.
QTc prolongation occurs at higher doses — relevant when combined with other QTc-prolonging agents or in patients with cardiac risk factors.
For situational anxiety in a young adult without controlled-substance options, hydroxyzine is a reasonable choice. For elderly patients, anticholinergic-sensitive patients, or daytime use requiring alertness, alternatives are usually better.
- Cost
- Generic: ~$5-15/month.
- Generic status
- Generic for decades.
- Formulary typical
- Tier 1 generic.
- Access friction
- None.
Prescriber tip: Cheap non-controlled alternative for PRN anxiety. Counsel about sedation and anticholinergic burden — particularly avoid in elderly.