Safety of Cetirizine for Pruritus in a 13-Week Pregnant Woman
Cetirizine (Zyrtec) should be used with caution during pregnancy, especially in the first trimester, but may be considered when the potential benefit outweighs the risk, as it is classified as FDA Pregnancy Category B with no evidence of teratogenicity in humans. 1, 2
Safety Profile in Pregnancy
- The FDA label for cetirizine recommends consulting a healthcare professional before use during pregnancy 2
- Cetirizine is classified as an FDA Pregnancy Category B drug, implying no evidence of harm to the fetus during pregnancy, although well-controlled human studies are limited 1
- It is generally best to avoid all antihistamines in pregnancy, especially during the first trimester, although none has been shown to be teratogenic in humans 1
- Prospective observational studies have not shown increased risk of major birth defects, spontaneous abortions, preterm deliveries, or adverse effects on birth weight with cetirizine use during pregnancy 3, 4
Alternative Options for Pregnant Women with Pruritus
- Chlorphenamine (chlorpheniramine) is often chosen by clinicians when antihistamine therapy is necessary during pregnancy because of its long safety record 1
- For pregnant women with pruritus without a rash, a thorough evaluation for underlying causes is essential, as pruritus may be a symptom of conditions like intrahepatic cholestasis of pregnancy (ICP) 1
- Non-pharmacological approaches should be considered first:
- Using emollients to prevent dryness of skin
- Avoiding hot baths or showers
- Using cooling gels (e.g., menthol gels) for affected skin areas
- Keeping nails shortened 1
Clinical Approach to Pruritus in Pregnancy
- Evaluate for signs of intrahepatic cholestasis of pregnancy (ICP), which typically presents with pruritus predominantly affecting the palms and soles, worse at night, and without a rash 1
- Consider laboratory evaluation including liver function tests and bile acids if ICP is suspected 1
- Rule out other causes of pruritus without rash in pregnancy, including:
- Liver disease
- Thyroid disorders
- Renal failure
- Drug reactions 1
Dosing Considerations
- If cetirizine is deemed necessary, use the lowest effective dose 1
- In patients with renal impairment, the dose of cetirizine should be halved 1
- Higher doses (up to 40 mg) may be more effective for urticaria and pruritus but should be avoided during pregnancy 5
Important Caveats
- The safety of cetirizine appears better established than hydroxyzine, which is specifically contraindicated during early pregnancy 1, 6
- Rare cases of paradoxical urticarial reactions to cetirizine have been reported 7
- The decision to use cetirizine during pregnancy should consider the severity of symptoms and impact on maternal quality of life versus potential risks 3
- Cetirizine is not effective for uraemic pruritus, though this is likely not relevant in pregnancy 1