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Desloratadine 3D ball-and-stick.png
Clinical data
Trade names Clarinex (US), Aerius (EU), others
AHFS/ Monograph
MedlinePlus a602002
License data
  • AU: B1
  • US: C (Risk not ruled out)
Routes of
Oral (tablets, solution)
ATC code
Legal status
Legal status
Pharmacokinetic data
Bioavailability Rapidly absorbed
Protein binding 83 to 87%
Metabolism Liver
Metabolites 3-Hydroxydesloratadine
Onset of action within 1 hour
Biological half-life 27 hours
Duration of action up to 24 hours
Excretion 40% as conjugated metabolites into urine
Similar amount into the feces
CAS Number
PubChem CID
ECHA InfoCard 100.166.554
Chemical and physical data
Formula C19H19ClN2
Molar mass 310.82 g/mol
3D model (JSmol)

Desloratadine (trade name Clarinex in the US and Aerius in Europe) is a tricyclic H1-antihistamine that is used to treat allergies. It is an active metabolite of loratadine.

Medical uses[edit]

Desloratadine is used to treat allergic rhinitis and nasal congestion.[1] It is the major metabolite of loratadine and the two drugs are similar in safety and effectiveness.[1] Desloratadine is available in many dosage forms and under many trade names worldwide.[2]

An emerging indication for desloratadine is in the treatment of acne, as an inexpensive adjuvant to isotretinoin and possibly as maintenance therapy or monotherapy.[3][4]

Side effects[edit]

The most common side-effects are fatigue, dry mouth, and headache.[1]


A number of drugs and other substances that are prone to interactions, such as ketoconazole, erythromycin and grapefruit juice, have shown no influence on desloratadine concentrations in the body. Desloratadine is judged to have a low potential for interactions.[5]


Mechanism of action[edit]

Desloratadine is a selective H1-antihistamine which functions as an inverse agonist at the histamine H1 receptor.[6]

At very high doses, is also an antagonist at various subtypes of the muscarinic acetylcholine receptors. This effect is not relevant for the drug's action at therapeutic doses.[7]


Desloratadine is well absorbed from the gut and reaches highest blood plasma concentrations after about three hours. In the bloodstream, 83 to 87% of the substance are bound to plasma proteins.[5]

An unidentified enzyme metabolizes it to 3-hydroxydesloratadine, which is then glucuronidized. Both desloratadine and 3-hydroxydesloratadine are eliminated via urine and feces with a half-life of 27 hours.[5][8]

It exhibits only peripheral activity since it does not readily cross the blood-brain barrier; hence, it does not normally cause drowsiness because it does not readily enter the central nervous system.[9]

3-Hydroxydesloratadine, the main metabolite


2% of Caucasian people and 18% of black people are desloratadine poor metabolizers. In these people, the drug reaches threefold highest plasma concentrations six to seven hours after intake, and has a half-life of about 89 hours. However, the safety profile for these subjects is not worse than for extensive (normal) metabolizers.[5][8]

See also[edit]