Fexofenadine; Uses, Dosage, Side Effects, Interactions

Last updated: July 6, 2026Reviewed date: July 6, 2026Reading time: 8 min read
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Medical guide Drugs (A - Z) Jul 6, 2026 62 reads
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Fexofenadine is a second generation, long-lasting selective histamine H1 receptor antagonist with the anti-inflammatory property. Fexofenadine is a highly selective and reversible competitor at peripheral H1 histamine receptors in the gastrointestinal (GI) tract, blood vessels, and bronchial smooth muscle. This agent interferes with mediators release from mast cells either by inhibiting calcium ion influx...

For severe symptoms, danger signs, pregnancy, child illness, or sudden worsening, seek urgent medical care.

বাংলা রোগী নোট এখনো যোগ করা হয়নি। পোস্ট এডিটরে “RX Bangla Patient Mode” বক্স থেকে সহজ বাংলা সারাংশ যোগ করুন।

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Article Summary

Fexofenadine is a second generation, long-lasting selective histamine H1 receptor antagonist with the anti-inflammatory property. Fexofenadine is a highly selective and reversible competitor at peripheral H1 histamine receptors in the gastrointestinal (GI) tract, blood vessels, and bronchial smooth muscle. This agent interferes with mediators release from mast cells either by inhibiting calcium ion influx across mast cell/basophil plasma membrane or by inhibiting intracellular calcium ion release within the cells. In addition, fexofenadine may also inhibit the late-phase allergic...

Key Takeaways

  • This article explains Mechanism of Action of Fexofenadine in simple medical language.
  • This article explains Indications of Fexofenadine in simple medical language.
  • This article explains Contra Indications of Fexofenadine in simple medical language.
  • This article explains Dosages of Fexofenadine in simple medical language.
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Definition

Fexofenadine is a second generation, long-lasting selective histamine H1 receptor antagonist with the infection, or irritation, often causing pain, swelling, heat, or redness. সহজ বাংলা: শরীরের প্রদাহ; ব্যথা, ফোলা বা লালভাব হতে পারে।" data-rx-term="inflammation" data-rx-definition="Inflammation is the body’s response to injury, infection, or irritation, often causing pain, swelling, heat, or redness. সহজ বাংলা: শরীরের প্রদাহ; ব্যথা, ফোলা বা লালভাব হতে পারে।">inflammation, pain, or swelling. সহজ বাংলা: প্রদাহ/ফোলা/ব্যথা কমায়।" data-rx-term="anti-inflammatory" data-rx-definition="Anti-inflammatory means reducing inflammation, pain, or swelling. সহজ বাংলা: প্রদাহ/ফোলা/ব্যথা কমায়।">anti-inflammatory property. Fexofenadine is a highly selective and reversible competitor at peripheral H1 histamine receptors in the gastrointestinal (GI) tract, blood vessels, and bronchial smooth muscle. This agent interferes with mediators release from mast cells either by inhibiting calcium ion influx across mast cell/basophil plasma membrane or by inhibiting intracellular calcium ion release within the cells. In addition, fexofenadine may also inhibit the late-phase allergic reaction by acting on leukotrienes or prostaglandins, or by producing an anti-platelet activating factor effect. Overall, this agent blocks the actions of endogenous histamine, thereby leads to temporary relief of the negative symptoms associated with histamine and achieve effects such as decreased vascular permeability, reduction of pruritus and localized smooth muscle relaxation.

Fexofenadine hydrochloride (Allegra) is an antihistamine drug used in the treatment of hayfever and similar allergy symptoms. It was developed as a successor of an alternative to terfenadine. Fexofenadine, like other second and third-generation antihistamines, does not readily pass through the blood-brain barrier, and so causes less drowsiness than first-generation histamine-receptor antagonists.

Fexofenadine is classified as a second-generation antihistamine because it is less able to pass the blood-brain barrier and cause sedation, compared to first-generation antihistamines.

Mechanism of Action of Fexofenadine

Fexofenadine competes with free histamine for binding at H1-receptors in the GI tract, large blood vessels, and bronchial smooth muscle. This blocks the action of endogenous histamine, which subsequently leads to temporary relief of the negative symptoms (eg. nasal congestion, watery eyes) brought on by histamine. Fexofenadine exhibits no anticholinergic, antidopaminergic, alpha1-adrenergic or beta-adrenergic-receptor blocking effects. Fexofenadine is a second-generation, long lasting H1-receptor antagonist (antihistamine) which has a selective and peripheral H1-antagonist action. Histamine is a chemical that causes many of the signs that are part of allergic reactions, such as the swelling of tissues. Histamine is released from histamine-storing cells (mast cells) and attaches to other cells that have receptors for histamine. The attachment of the histamine to the receptors causes the cell to be “activated,” releasing other chemicals which produce the effects that we associate with allergy. Fexofenadine blocks one type of receptor for histamine (the H1 receptor) and thus prevents activation of cells by histamine. Unlike most other antihistamines, Fexofenadine does not enter the brain from the blood and, therefore, does not cause drowsiness. Fexofenadine lacks the cardiotoxic potential of terfenadine since it does not block the potassium channel involved in repolarization of cardiac cells.

or

It has been suggested that the increased safety profile of fexofenadine compared with the parent drug results from the lack of fexofenadine-induced cardiotoxicity in addition to only minimal metabolism of fexofenadine in the liver by the cytochrome P-450 microsomal enzyme system. Evidence from animal models using fexofenadine have suggested that the apparent lack of cardiotoxic effects of the drug may have resulted at least in part from lack of blockade of the potassium channel involved in repolarization of cardiac cells (ie, blockade of the delayed rectifier potassium current IK). Prolongations in the QTc interval were not reported in dogs receiving oral fexofenadine hydrochloride dosages of 10 mg/kg daily for 5 days or in rabbits receiving an IV fexofenadine hydrochloride dose of 10 mg/kg (resulting in plasma fexofenadine concentrations 28 or 63 times the therapeutic plasma concentrations in humans, respectively, based on a dosage of 60 mg of fexofenadine hydrochloride given twice daily). In addition, no effect was observed on calcium-channel current, delayed potassium-channel current, or action potential duration in guinea pig myocytes, sodium current in rat neonatal myocytes, or on the delayed rectifier potassium channel cloned from human heart at fexofenadine concentrations up to 1.0 X10-5 M (approximately equivalent to 32 times the therapeutic plasma concentrations in humans, based on a dosage of 60 mg of fexofenadine hydrochloride given twice daily)

Indications of Fexofenadine

Contra Indications of Fexofenadine

  • kidney disease with reduction in kidney function
Allergies
  • Antihistamines
  • Antihistamines – Piperidine

Dosages of Fexofenadine

Strengths : 30mg, 60mg ,180mg Tablets

Oral suspension : 30mg/5mL

 Allergic Rhinitis

  • 180 mg orally once a day OR 60 mg orally 2 times a day
  • Maximum dose: 180 mg/day.

Urticaria

  • 180 mg orally once a day OR 60 mg orally 2 times a day
  • Maximum dose: 180 mg/day.

Pediatric dosage

Allergic Rhinitis

  • 6 months to 2 years: 15 mg orally 2 times a day
  • 2 years to 11 years: 30 mg orally 2 times a day
  • 12 years and older: 180 mg orally once a day OR 60 mg orally 2 times a day

Urticaria

  • 6 months to 2 years: 15 mg orally 2 times a day
  • 2 years to 11 years: 30 mg orally 2 times a day
  • 12 years and older: 180 mg orally once a day OR 60 mg orally 2 times a day

Side Effects of Fexofenadine

The most common

More common

Less common

 Drug Interactions of Fexofenadine

Fexofenadine may interact with following drugs, supplements & may change the efficacy of drugs

Antacids containing aluminum or magnesium should not be taken within 15 minutes of fexofenadine as they reduce the absorption of fexofenadine by almost 50%. This is not thought to be due to a change in pH (in fact, absorption can actually increase under increasingly alkaline pH), but rather due to the formation of metal complexes with charged/polar moieties on fexofenadine. As suggested by Shehnaza et al (2014), various sites of the molecule are thought to be responsible for this interaction, including the piperidine nitrogen, the carboxylic acid (-COOH) group, and both hydroxyl (-OH) groups. Meals with high amounts of fat decrease the absorption of fexofenadine by about 50%.

Pregnancy & Lactation of Fexofenadine

 FDA pregnancy category C

Pregnancy

This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Lactation

Fexofenadine passes into breast milk. This medication should not be used by breastfeeding women.

References

Fexofenadine; Uses, Dosage, Side Effects, Interactions

 

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