What is the recommended dose of Vistaril (hydroxyzine) for pregnancy rest?

Vistaril (Hydroxyzine) Should Be Avoided During Pregnancy

Hydroxyzine is specifically contraindicated during early pregnancy and should not be used for pregnancy rest or any indication during gestation. 1

Guideline Recommendations

Contraindication Status

• Hydroxyzine is the only antihistamine specifically contraindicated during the early stages of pregnancy according to U.K. manufacturer's Summary of Product Characteristics 1
• All antihistamines should ideally be avoided in pregnancy, especially during the first trimester, though hydroxyzine carries the most explicit contraindication 1

Pregnancy Category Classification

• Hydroxyzine is mentioned in pregnancy risk category discussions but lacks the safety profile of alternative agents 1
• The drug does not have the established safety record of other antihistamines like chlorphenamine, which is often chosen when antihistamine therapy is necessary in pregnancy 1

Clinical Evidence of Harm

Neonatal Withdrawal Syndrome

• High-dose hydroxyzine (600 mg daily) throughout pregnancy has been associated with neonatal withdrawal syndrome 2
• A confirmed case of neonatal seizures occurred with maternal hydroxyzine treatment at 150 mg/day, verified by plasma concentration measurements in both mother and infant 3
• Neurological symptoms in neonates with low hydroxyzine concentrations suggest a withdrawal syndrome mechanism 3

Safety Data Limitations

• While one prospective controlled study of 53 women exposed to hydroxyzine during organogenesis found no significant increase in major malformations 4, this does not override the documented cases of neonatal complications and the explicit contraindication in guidelines
• The risk-benefit analysis does not favor hydroxyzine use when safer alternatives exist 1

Safer Alternatives for Pregnancy

First-Line Antihistamine Choice

• Chlorphenamine (chlorpheniramine) is the preferred antihistamine in U.K. clinical practice during pregnancy due to its long safety record 1
• Dosing: 4-12 mg at night if sedating antihistamine is needed 1

U.S. FDA Category B Options

• Loratadine and cetirizine are classified as FDA Pregnancy Category B drugs, indicating no evidence of harm to the fetus, though well-controlled human studies are not available 1
• Cetirizine, the active metabolite of hydroxyzine, appears safer with prospective data showing no increased teratogenic risk 4

Critical Clinical Pitfalls

• Do not prescribe hydroxyzine at any dose for pregnant women, regardless of the indication including "pregnancy rest" 1
• Clinicians must be warned of possible rare neurological complications in neonates born to mothers treated long-term with hydroxyzine 3
• If a patient has been taking hydroxyzine and becomes pregnant, switch immediately to chlorphenamine or a Category B antihistamine 1
• The sedating effects that might be desired for "rest" can be achieved more safely with chlorphenamine 1