Fexofenadine is an antihistamine used to relieve allergy symptoms such as watery eyes, runny nose, itching eyes/nose, sneezing, hives, and itching. It works by blocking a certain natural substance (histamine) that your body makes during an allergic reaction.
H1-Receptor Antagonist; Non-sedating Antihistamine
The H1 histamine receptor is responsible for mediating hypersensitivity and allergic reactions. Exposure to allergen results in the degranulation of mast cells and basophils, which then release histamine and other inflammatory mediators. Histamine binds to, and activates, H1 receptors, which results in the further release of pro-inflammatory cytokines, such as interleukins, from basophils and mast cells. These downstream effects of histamine binding are responsible for a wide variety of allergic symptoms, such as pruritus, rhinorrhea, and watery eyes.
Fexofenadine is considered an "inverse agonist" of the H1 receptor because it binds to and stabilizes the inactive form of the receptor, preventing its activation and subsequent downstream effects. It has a potent and selective affinity for H1 receptors, and there is no evidence that it carries antidopaminergic, antiserotonergic, anticholinergic, sedative, or adrenergic blocking activity. Fexofenadine does not cross the blood-brain barrier and thus is unlikely to cause significant CNS effects.
ORAL Seasonal allergic rhinitis: Adult: 120 mg once daily. Child: 6-11 yr: 30 mg bid. Chronic idiopathic urticaria: Adult: 180 mg once daily. Child: 6 mth-<2 yr: 15 mg bid; 2 yr: 30 mg bid.
Fexofenadine does not undergo hepatic biotransformation and therefore will not interact with other medicinal products through hepatic mechanisms. Coadministration of fexofenadine hydrochloride with erythromycin or ketoconazole has been found to result in a 2-3 times increase in the level of fexofenadine in plasma. The changes were not accompanied by any effects on the QT interval and were not associated with any increase in adverse reactions compared to the medicinal products given singly. No interaction between fexofenadine and omeprazole was observed. However, the administration of an antacid containing aluminium and magnesium hydroxide gels 15 minutes prior to fexofenadine hydrochloride caused a reduction in bioavailability, most likely due to binding in the gastrointestinal tract. It is advisable to leave 2 hours between administration of fexofenadine hydrochloride and aluminium and magnesium hydroxide containing antacids.
Hypersensitivity. Renal impairment. Pregnancy, lactation; child <6 yr.
Viral infection (cold/flu); headache, dizziness, drowsiness, fatigue: nausea, dyspepsia, dysmenorrhoea.
Use is not recommended unless clearly needed during pregnancy. Use is not recommended while breastfeeding.
Dizziness, drowsiness, fatigue and dry mouth have been reported with overdose of Fexofenadine hydrochloride. Single doses up to 800 mg and doses up to 690 mg twice daily for 1 month or 240 mg once daily for 1 year have been administered to healthy subjects without the development of clinically significant adverse reactions as compared with placebo. The maximum tolerated dose of Fexofenadine hydrochloride has not been established. Standard measures should be considered to remove any unabsorbed medicinal product. Symptomatic and supportive treatment is recommended. Haemodialysis does not effectively remove Fexofenadine hydrochloride from blood.
Keep in a dry place away from light and heat. Keep out of the reach of children.
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