Desloratadine (des-lor-at’ah-deen) is a second generation tricyclic H1 inverse agonist that is used to treat allergies such as allergic rhinitis and chronic idiopathic urticaria (hives). It is an active metabolite of loratadine. Mostly acts peripherally as it does not readily cross the blood-brain barrier, so is less drowsy than the earlier antihistamines.
Mechanism of action:
Desloratadine competes with histamine for binding at the H1 receptors in the gastrointextinal tract, blood vessels, uterus and bronchial smooth muscle to blocks the action of the endogenous histamine/ This leads to relief of the symptoms caused by the histamine (eg nasal congestion and watery eyes).
Onset in about 1 hr; peaks at 1.5hrs; duration of 24 hours.
Pharmacokinetics:
Rapidly absorbed in the gut; protein binding is 83 to 87%;
Metabolised by UGT2B10 and CYP2C8 to 3-Hydroxydesloratadine
Onset of action within 1 hour; duration pf action up to 24 hours
Elimination half-life is 27 hours; eliminated via urine and feces.
Brand names: Clarinex, Aerius, Azomyr, Dasselta, Desloratadine, Neoclarityn
Chemical formula: C19H19ClN2
Dosage:
Adults and children 12 years or older: typically 5 mg by mouth once daily, with or without food.
Contraindication: Hypersensitivity
Cautions: Pregnancy C, asthma, renal or hepatic impairment, child, breastfeeding
Interactions: Etravirine and nilotinib increase the effect of desloratadine
Side effects:
Common: dry mouth, sore throat; muscle aches; fatigue; drowsiness (less common than other antihistamines); menstrual pain
In Australia, Desloratadine is on the National Podiatry Scheduled Medicines List for use by authorised Podiatrists.
Examples of other H1 Antagonists (Anti-histamines):
| Highly Sedative: | Moderately Sedative: | Mildly Sedative: | Not Sedative: |
| Promethazine Hydroxyzine Dimenhydinate | Pheniramine Meclozine Cinnarizine | Triprolidine Clemastine Chlorpheniramine Dexchlorpheniramine | Desloratadine Fexofenadine Loratadine |
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