2nd-generation H1 antihistamines are only available in oral formulations and include the following:
| Cetirizine (Zyrtec) 10mg PO QD for adults and children 6 years and older. May be increased to BID in adults if needed. use 5mg PO QD for children aged 2-5 year sold. 2.5mg QD for children 6 mo to 2 years. Minimum age for use: 6 months |
| Levocetirizine 5mg PO QD for adults and children 12 years and older. Adults may increase to 5mg BID. Note: Levocetirizine is an active enantiomer of cetirizine that produces effects equivalent to cetirizine at about half the dose. |
| Loratadine (Claritin) 10mg PO QD for adults and children 6 years and older. Adults may increase to BID. Minimum age for use: 2 years |
| Desloratadine 5mg PO QD for adults and children 12 years and older. Adults may increase to BID Minimum age for use: 6 months |
| Fexofenadine (Allegra) 180 mg QD for ages 12 years and older (or up to twice daily in adults if needed) Minimum age for use: 2 years (allergic rhinitis) |