[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [H1 antihistamines](https://durgical.com/en/pharmacology/classes/h1-antihistamines/) › Desloratadine

# Desloratadine

## H1 antihistamines?

H1 antihistamines

The active metabolite of loratadine, a once-daily non-sedating antihistamine for allergic rhinitis and chronic hives.

Updated Nov 1, 2026

## Quick facts

**Group**
[H1 antihistamines](https://durgical.com/en/pharmacology/classes/h1-antihistamines/)

**Target**
Histamine H1 receptor

**Used for**
Allergic rhinitis · Chronic idiopathic urticaria

**Key effects**
Headache · Mild drowsiness or tiredness · Dry mouth

**Monitor**
Symptom relief

**ATC**
R06AX27

No doses: the clinician sets them by the current guideline.

On this page

- The basics Mechanism of action
- Indications
- Adverse effects
- Pharmacokinetics
- Memory aid

- Safety Contraindications
- Key interactions
- What is monitored
- Administration and safety
- Pregnancy and breastfeeding
- Nursing care

- Study Test yourself

- Connections Connections

## Mechanism of action

◎**Histamine H1 receptor**Desloratadine

ⓘ The figure shows desloratadine bound to the human histamine H1 receptor (cryo-electron microscopy).

**Target in 3D:** Histamine H1 receptor. PDB structure 8X64 (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/8X64) · Drag to rotate · pinch to zoom

Desloratadine is the main active metabolite of loratadine, given directly. It is a long-acting peripheral H1 inverse agonist that does not need liver activation and causes little sedation. Some people are slow metabolisers of desloratadine and have higher levels, usually without more side effects.

- Desloratadine is absorbed already in its active form
- It binds peripheral H1 receptors and keeps them inactive
- Sneezing, itch and wheals are reduced
- It barely enters the brain

## Indications

- Allergic rhinitis [Allergic rhinitis →](https://durgical.com/en/conditions/allergic-rhinitis/)
- Chronic idiopathic urticaria [Urticaria and angioedema →](https://durgical.com/en/conditions/urticaria-and-angioedema/)

## Adverse effects

### Common

- Headache
- Mild drowsiness or tiredness in some people
- Dry mouth

### Serious (rare, important)

- Hypersensitivity reactions, including anaphylaxis: rare

## Contraindications

- Hypersensitivity to desloratadine or loratadine
- Caution in liver or kidney impairment

## Key interactions

**Ketoconazole, erythromycin**
Raise levels without clinically relevant changes in studies

**Alcohol, benzodiazepines, opioids and other CNS depressants**
Additive sedation and slowed breathing

## What is monitored

- Symptom relief

## Administration and safety

- Oral tablets, orally disintegrating tablets or solution, once a day
- Not combined with loratadine: it is the same active substance

## Pregnancy and breastfeeding

Human pregnancy data are limited; loratadine, which has more data, is often preferred.

## Nursing care

- Check that the patient is not also taking loratadine
- Teach that drowsiness is uncommon but possible

## Pharmacokinetics

**Absorption**
Well absorbed by mouth, with or without food

**Metabolism**
Liver to 3-hydroxydesloratadine; some people are slow metabolisers

**Elimination**
Urine and faeces

**Onset and duration**
Within about an hour, lasting about a day

## Memory aid

DESloratadine = loratadine with the liver step DESkipped.

## Test yourself

Think of the answer, then tap the question to see it.

## What is the relationship between desloratadine and loratadine?

Desloratadine is the main active metabolite of loratadine.

## Does desloratadine need liver activation to work?

No; it is already the active form.

## What are two indications of desloratadine?

Allergic rhinitis and chronic idiopathic urticaria.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/desloratadine/)

[More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology)

## Connections

## Related drugs 3

- [Loratadine](https://durgical.com/en/pharmacology/loratadine/)
- [Fexofenadine](https://durgical.com/en/pharmacology/fexofenadine/)
- [Cetirizine](https://durgical.com/en/pharmacology/cetirizine/)

## Related conditions 2

- [Allergic rhinitis](https://durgical.com/en/conditions/allergic-rhinitis/)
- [Urticaria and angioedema](https://durgical.com/en/conditions/urticaria-and-angioedema/)

[← Back to the class: H1 antihistamines](https://durgical.com/en/pharmacology/classes/h1-antihistamines/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [DailyMed - DESLORATADINE tablet, film coated](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=2a90b899-7746-43dc-ac8a-e754428eb30c) (DailyMed (U.S. National Library of Medicine), 2026); [Desloratadine: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a602002.html) (MedlinePlus (U.S. National Library of Medicine), 2026); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=R06AX27) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/pharmacology/desloratadine/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/desloratadine/