Allergic rhinitis: Fexofenadine is indicated for the relief of symptoms associated with seasonal and perennial allergic rhinitis in adults and children aged 12 years and older. It effectively relieves symptoms such as sneezing, rhinorrhea, lacrimation, itchy and red eyes, and itching of the nose, palate, or throat. Fexofenadine also enhances health-related quality of life and improves work and daily activity productivity.

The H1 histamine receptor plays a key role in mediating allergic and hypersensitivity reactions. When an allergen is encountered, mast cells and basophils release histamine and other inflammatory mediators. Histamine binds to H1 receptors, triggering the release of pro-inflammatory cytokines, such as interleukins, from mast cells and basophils. These actions lead to common allergic symptoms, including itching (pruritus), runny nose (rhinorrhea), and watery eyes.

Fexofenadine acts as an "inverse agonist" at the H1 receptor. It binds to the receptor in its inactive state, stabilizing it and preventing activation and subsequent inflammatory effects. Fexofenadine has a strong and selective affinity for H1 receptors and does not show antidopaminergic, antiserotonergic, anticholinergic, sedative, or adrenergic blocking activities. It does not cross the blood-brain barrier, making significant central nervous system (CNS) effects unlikely.

Allergic Rhinitis-

Adults and children 12 years and older:

• Tablet: 60 mg twice daily or 120 mg once daily or 180 mg once daily

Children from 6 to 11 years:

• Tablet: 30 mg twice daily or 60 mg once daily
• In case of impaired renal function: 30 mg once daily

Children from 2 to 11 years

• Suspension: 30 mg or 5 ml twice daily
• In case of impaired renal function: 30 mg or 5 ml once daily

Chronic Idiopathic Urticaria-

Adults and children 12 years and older:

• Tablet: 60 mg twice daily or 120 mg once daily or 180 mg once daily
• In case of impaired renal function: 60 mg once daily

Children from 6 to 11 years:

• Tablet: 30 mg twice daily or 60 mg once daily
• In case of impaired renal function: 30 mg once daily

Children from 6 months to less than 2 years:

• Suspension: 15 mg or 2.5 ml (1/2 tsp) twice daily
• In case of impaired renal function: 15 mg or 2.5 ml (1/2 tsp) once daily

Children from 2 to 11 years:

• Suspension: 30 mg or 5 ml (1 tsp) twice daily
• In case of impaired renal function: 30 mg or 5 ml (1 tsp) once daily

Fexofenadine does not undergo hepatic metabolism and therefore is unlikely to interact with other medicines through liver-based mechanisms. Concomitant use of fexofenadine hydrochloride with erythromycin or ketoconazole has been shown to increase plasma concentrations of fexofenadine by two to three times. These changes were not associated with any effect on the QT interval or an increase in adverse reactions compared with either drug administered alone. No interaction has been observed between fexofenadine and omeprazole.

However, taking an antacid containing aluminum or magnesium hydroxide gels 15 minutes before fexofenadine hydrochloride may reduce its bioavailability, likely due to binding within the gastrointestinal tract. It is recommended to allow a 2-hour interval between fexofenadine hydrochloride and antacids containing aluminum or magnesium hydroxide.

Contraindicated in patients with known hypersensitivity to fexofenadine hydrochloride or any of its components.

The following frequency categories are used, where applicable:

Very common (≥1/10); Common (≥1/100 to <1/10); Uncommon (≥1/1,000 to <1/100); Rare (≥1/10,000 to <1/1,000); Very rare (<1/10,000); and Not known (frequency cannot be estimated from available data). Within each frequency category, adverse reactions are listed in order of decreasing seriousness.

In adults, the following adverse reactions were reported in clinical trials at an incidence similar to placebo:

• Nervous system disorders – Common: headache, drowsiness, dizziness
• Gastrointestinal disorders – Common: nausea
• General disorders and administration site conditions – Uncommon: fatigue

In post-marketing surveillance, the following adverse reactions have been reported in adults; their frequency is unknown (cannot be estimated from available data):

• Immune system disorders – hypersensitivity reactions including angioedema, chest tightness, dyspnea, flushing, and systemic anaphylaxis
• Psychiatric disorders – insomnia, nervousness, sleep disturbances, nightmares, or excessive dreaming (paroniria)
• Cardiac disorders – tachycardia, palpitations
• Gastrointestinal disorders – diarrhea
• Skin and subcutaneous tissue disorders – rash, urticaria, pruritus

There are no adequate data regarding the use of fexofenadine hydrochloride in pregnant women. Limited animal studies do not suggest any direct or indirect harmful effects on pregnancy, embryonic or fetal development, parturition, or postnatal development. Fexofenadine hydrochloride should therefore be used during pregnancy only if clearly necessary.

There are no data on the presence of fexofenadine in human breast milk following administration of fexofenadine hydrochloride. However, after administration of terfenadine to nursing mothers, fexofenadine was detected in human breast milk. For this reason, fexofenadine hydrochloride is not recommended for use in breastfeeding mothers.

No human data are available regarding the effects of fexofenadine hydrochloride on fertility. In animal studies, specifically in mice, no effects on fertility were observed following treatment with fexofenadine hydrochloride.

As with most newly introduced medicinal products, available data in elderly patients and in those with renal or hepatic impairment are limited. Fexofenadine hydrochloride should therefore be used with caution in these patient groups. Individuals with a history of, or existing, cardiovascular disease should be advised that antihistamines as a class have been associated with adverse reactions such as tachycardia and palpitations.

Effects on ability to drive and use machines:
Based on its pharmacodynamic profile and reported adverse reactions, fexofenadine hydrochloride tablets are unlikely to impair the ability to drive or operate machinery. Objective studies have demonstrated no significant effects on central nervous system function. Patients may therefore drive or perform tasks requiring concentration. However, to identify individuals who may have an unusual sensitivity to the medication, it is advisable to assess personal response before driving or undertaking complex activities.

Renal and hepatic impairment: The pharmacokinetics of fexofenadine are altered in patients with renal impairment. Due to increased bioavailability and prolonged half-life, a starting dose of 60 mg once daily is recommended for patients with reduced renal function. Moderate to severe hepatic impairment does not significantly affect the pharmacokinetics of fexofenadine.

Elderly patients: The incidence of adverse events in elderly patients is similar to that observed in individuals under 65 years of age. However, pharmacokinetic changes, including increased bioavailability, have been observed in patients older than 65 years.

Dizziness, drowsiness, fatigue, and dry mouth have been reported in cases of fexofenadine hydrochloride overdose. Single doses of up to 800 mg, doses of 690 mg twice daily for one month, and 240 mg once daily for one year have been administered to healthy subjects without clinically significant adverse effects compared with placebo. The maximum tolerated dose of fexofenadine hydrochloride has not been established.

In cases of overdose, standard measures should be taken to eliminate any unabsorbed drug. Symptomatic and supportive treatment is recommended. Hemodialysis is not effective in removing fexofenadine hydrochloride from the bloodstream.

Non-sedating antihistamines.

Store in a dry place, protected from light and heat. Keep out of reach of children.