What is the maximum recommended dose of hydroxyzine (antihistamine) during pregnancy?

Maximum Recommended Dose of Hydroxyzine During Pregnancy

Hydroxyzine should be used cautiously during pregnancy, especially in the first trimester, with a maximum recommended dose of 50 mg per day when absolutely necessary. 1

Safety Classification and Recommendations

Hydroxyzine has important safety considerations during pregnancy:

• Hydroxyzine is specifically contraindicated during early pregnancy according to UK manufacturer's Summary of Product Characteristics 1
• It is classified as FDA Pregnancy Category C, indicating potential risks based on animal studies 1
• When antihistamine therapy is necessary during pregnancy, other options like chlorphenamine (chlorpheniramine) are often preferred due to their longer safety record 1

Dosing Guidelines When Use Is Unavoidable

If hydroxyzine must be used during pregnancy (when benefits clearly outweigh risks):

• Start with the lowest effective dose (10-25 mg)
• Do not exceed 50 mg daily during pregnancy
• Use for the shortest duration possible
• Consider alternative antihistamines with better pregnancy safety profiles

Potential Risks and Concerns

Several case reports highlight specific concerns with hydroxyzine use during pregnancy:

• High doses (600 mg daily) have been associated with neonatal withdrawal syndrome 2
• Even moderate doses (150 mg daily) have been linked to neonatal seizures 3
• These risks appear dose-dependent, emphasizing the importance of using the lowest effective dose

Alternative Antihistamines During Pregnancy

When antihistamine therapy is necessary during pregnancy:

• Chlorphenamine (4-12 mg daily) is often preferred due to its established safety record 1
• Loratadine and cetirizine are classified as FDA Pregnancy Category B drugs, suggesting potentially better safety profiles 1, 4
• A prospective controlled study found no increased teratogenic risk with cetirizine use during pregnancy 5, 4

Special Considerations

• For renal impairment: The dose of hydroxyzine should be halved in moderate renal impairment and avoided entirely in severe renal impairment 1
• For hepatic impairment: Hydroxyzine should be avoided in severe liver disease 1
• First trimester exposure carries the highest theoretical risk during organogenesis 1

Clinical Decision Algorithm

1. First, consider non-pharmacological approaches for symptom management
2. If medication is necessary, consider second-generation antihistamines with Pregnancy Category B classification (loratadine, cetirizine)
3. If hydroxyzine is specifically indicated:
   • Use only when clearly necessary
   • Start with 10-25 mg per dose
   • Do not exceed 50 mg total daily dose
   • Monitor for maternal and fetal effects
   • Discontinue before delivery if possible to minimize risk of neonatal effects

The evidence suggests a cautious approach with hydroxyzine during pregnancy, with careful consideration of risks versus benefits and use of the lowest effective dose for the shortest duration necessary.