What is Desloratadine?

Desloratadine is a biologically active metabolite of the second-generation antihistamine loratadine. It is a highly selective peripheral H1 receptor antagonist and belongs to the antihistamine group of drugs. It is indicated for the treatment of allergic rhinitis and urticaria in adults and children. It can be used to relieve sneezing, runny nose, red, itchy, watery eyes, red, swollen, itchy skin and rashes.

What is Loratadine?

Loratadine is a pre-drug of Desloratadine, also an antihistamine, and has similar indications to Desloratadine. It may be used for temporary relief of allergy symptoms, including a runny or stuffy nose, sneezing, tearing, and itchy eyes, nose, or throat. It may also be used to treat itching and redness caused by hives. However, the medicine is not as strong as desloratadine.

Differences between Desloratadine and Loratadine

The results of the study showed that the anti-allergic effect of Desloratadine is not related to its antagonistic effect on histamine. Desloratadine exerts its therapeutic effect by inhibiting the expression of cell adhesion molecules, inhibiting the production and release of inflammatory mediators and cytokines, and attenuating eosinophil chemotaxis, adhesion and superoxide production. Loratadine, on the other hand, relieves allergy symptoms by inhibiting the production of histamine, a substance in the body that causes allergy symptoms. Furthermore, Desloratadine is significantly more effective than Loratadine and is well tolerated with fewer side effects.

Clinical studies have shown that oral desloratadine is rapidly absorbed and its bioavailability is not affected by food. It does not cross the blood-brain barrier and therefore does not cause sedation or impair cognitive or psychomotor performance. It also does not affect the QRS and QTc intervals, which can lead to arrhythmias. Desloratadine has no significant effect on gastrointestinal function. The overall safety profile is excellent. Increased patient satisfaction with treatment after switching from loratadine to desloratadine has been reported.

In addition, studies of anti-allergy treatment in bariatric patients found that crushing the tablets did not increase the solubility of loratadine in any post-bariatric surgery condition, nor did loratadine syrup increase its solubility in OAGB postoperative (pH 7) media, whereas the syrup partially improved its solubility by up to 40 per cent in laparoscopic SG postoperative (pH 5) conditions. In contrast, desloratadine dissolved rapidly and completely in all pre- and post-surgical conditions. Therefore, desloratadine should be preferred to loratadine in bariatric patients.

References:

[1] TADAHO NAKAMURA. Brain histamine H1 receptor occupancy measured by PET after oral administration of desloratadine and loratadine[J]. Proceedings for Annual Meeting of The Japanese Pharmacological Society, 2019. DOI:10.1254/JPSSUPPL.92.0\_3-O-25.

[2] DANIEL GLASS; Anne H. Assessing patient satisfaction with desloratadine after conversion from loratadine, fexofenadine, or cetirizine.[J]. Managed care interface, 2004.

[3] DANIEL PORAT, ARIK DAHAN*; Antiallergic Treatment of Bariatric Patients: Potentially Hampered Solubility/Dissolution and Bioavailability of Loratadine, but Not Desloratadine, Post-Bariatric Surgery[J]. Molecular Pharmaceutics, 2022. DOI:10.1021/acs.molpharmaceut.2c00292.

[4] AGRAWAL D. Pharmacology and clinical efficacy of desloratadine as an anti-allergic and anti-inflammatory drug[J]. Expert opinion on investigational drugs, 2001, 10 1: 547-560. DOI:10.1517/13543784.10.3.547.