Antihistamine
Desloratadine is a second-generation H1 antagonist that causes less sedation and psychomotor impairment than older antihistamines because it penetrates the blood brain barrier only to a slight extent. Its effect is confined to the suppression of symptoms attributable to histamine released by antigen-antibody reactions.
Most manufacturers advise avoiding use during pregnancy; however, there is no evidence of teratogenicity.
Most antihistamines are present in breast milk in varying amounts; although not known to be harmful, most manufacturers advise avoiding their use in mothers who are breast-feeding.
Additive CNS depressant effects, potentially leading to increased drowsiness, sedation, impaired psychomotor performance, and reduced alertness.
Advise patients to avoid or limit alcohol consumption while taking desloratadine, especially during activities requiring mental alertness (e.g., driving, operating machinery). While desloratadine is less sedating than older antihistamines, the combination with alcohol can still be problematic.
Increased plasma concentrations of desloratadine and its active metabolite, 3-hydroxydesloratadine, leading to a potential for increased antihistaminic effects.
Monitor for increased antihistaminic effects (e.g., sedation). While desloratadine has a good safety profile, caution is advised. Dose adjustment of desloratadine is generally not required based on current evidence, but individual patient response should be considered.
Increased plasma concentrations of desloratadine and its active metabolite, 3-hydroxydesloratadine, leading to a potential for increased antihistaminic effects. While desloratadine has a good cardiac safety profile, the combination with other QTc-prolonging drugs should be considered with caution.
Monitor for increased antihistaminic effects (e.g., sedation). While desloratadine has a good safety profile, caution is advised, especially in patients with pre-existing cardiac conditions. Dose adjustment of desloratadine is generally not required based on current evidence, but individual patient response should be considered.
Increased plasma concentrations of desloratadine and its active metabolite, 3-hydroxydesloratadine, leading to a potential for increased antihistaminic effects. While desloratadine has a good cardiac safety profile, the combination with other QTc-prolonging drugs should be considered with caution.
Monitor for increased antihistaminic effects (e.g., sedation). While desloratadine has a good safety profile, caution is advised, especially in patients with pre-existing cardiac conditions. Dose adjustment of desloratadine is generally not required based on current evidence, but individual patient response should be considered.
Source: DDInter
Increased plasma concentrations of desloratadine and its active metabolite, 3-hydroxydesloratadine, leading to a potential for increased antihistaminic effects and possibly a slight increase in QTc interval, though generally not clinically significant with desloratadine alone.
Monitor for increased antihistaminic effects (e.g., sedation). While desloratadine has a good safety profile, caution is advised, especially in patients with pre-existing cardiac conditions. Dose adjustment of desloratadine is generally not required based on current evidence, but individual patient response should be considered.
Source: DDInter
Significantly increased plasma concentrations of desloratadine and its active metabolite, 3-hydroxydesloratadine, leading to a potential for increased antihistaminic effects and possibly a slight increase in QTc interval, though generally not clinically significant with desloratadine alone.
Monitor closely for increased antihistaminic effects (e.g., sedation). While desloratadine has a good safety profile, the magnitude of interaction with potent inhibitors like ritonavir warrants caution. Consider using an alternative antihistamine or reducing the desloratadine dose if adverse effects occur.
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Sources: KD Tripathi 7e, Goodman & Gilman 14e, Katzung, BNF·Verified: 2026-05-10 · House clinical team