[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/) › Fexofenadine

# Fexofenadine

## H1 antihistamines?

H1 antihistamines

The least sedating second-generation antihistamine; fruit juices and some antacids reduce its absorption.

Updated Nov 1, 2026

## Quick facts

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

**Target**
Histamine H1 receptor

**Used for**
Seasonal allergic rhinitis · Chronic hives

**Key effects**
Headache · Nausea or indigestion · Dizziness

**Monitor**
Symptom relief

**ATC**
R06AX26

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**Fexofenadine

ⓘ The figure shows desloratadine bound to the human histamine H1 receptor (cryo-electron microscopy); fexofenadine binds the same site.

**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

Fexofenadine is the active metabolite of terfenadine, an older antihistamine withdrawn because it prolonged the QT interval. Fexofenadine keeps the peripheral H1 inverse agonism without that cardiac effect. It is a substrate of P-glycoprotein, which keeps it out of the brain, so it causes essentially no sedation.

- Fexofenadine binds peripheral H1 receptors
- Histamine itch, sneezing and wheals are blocked
- P-glycoprotein pumps it out of the brain: no sedation
- It is not metabolised much and leaves in bile and urine

## Indications

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

## Adverse effects

### Common

- Headache
- Nausea or indigestion
- Dizziness

### Serious (rare, important)

- Allergic reaction to the drug: rare

## Contraindications

- Hypersensitivity to fexofenadine
- Caution in kidney disease

## Key interactions

**Fruit juices (grapefruit, orange, apple)**
Reduce absorption by blocking intestinal uptake transporters

**Antacids with aluminium or magnesium**
Reduce absorption; they are separated by a few hours

## What is monitored

- Symptom relief

## Administration and safety

- Swallowed with water, not with fruit juice
- Separated by a few hours from aluminium or magnesium antacids
- Combination tablets with pseudoephedrine exist

## Pregnancy and breastfeeding

Human pregnancy data are fewer than for loratadine or cetirizine; use is decided with the clinician.

## Nursing care

- Teach to take it with water and not with fruit juice
- Ask about antacids and space them apart
- Useful for people who must stay alert, such as drivers or pilots

## Pharmacokinetics

**Absorption**
Oral; reduced by fruit juices (grapefruit, orange, apple) and by aluminium- or magnesium-containing antacids

**Metabolism**
Very little

**Elimination**
Mainly unchanged in faeces (bile) and some in urine

**Onset and duration**
Within a few hours

## Memory aid

FEXofenadine: FEW eXtras: no sedation, no QT problem, but no fruit juice.

## Test yourself

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

## Which older antihistamine is fexofenadine the active metabolite of, and why was that drug withdrawn?

Terfenadine; it prolonged the QT interval and caused arrhythmias.

## Why should fexofenadine not be taken with orange or grapefruit juice?

The juices reduce its intestinal absorption and therefore its effect.

## Why does fexofenadine cause almost no sedation?

P-glycoprotein pumps it out of the brain.

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

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

## Connections

## Related drugs 3

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

## 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: [Fexofenadine: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a697035.html) (MedlinePlus (U.S. National Library of Medicine), 2026); [Fexofenadine: antihistamine medicine that relieves allergy symptoms - NHS](https://www.nhs.uk/medicines/fexofenadine/) (NHS, 2026); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=R06AX26) (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/fexofenadine/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/fexofenadine/