Fexofenadine is a second-generation antihistamine medication used primarily for the treatment of allergic conditions such as allergic rhinitis (hay fever) and chronic idiopathic urticaria (hives). It provides rapid and long-lasting relief of symptoms with once-daily dosing, making it a convenient option.
Key points:
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Mechanism of Action: Fexofenadine belongs to the class of antihistamine drugs known as H1 receptor antagonists. It works by selectively blocking the effects of histamine at H1 receptors, thereby alleviating symptoms such as sneezing, itching, runny nose, and watery eyes caused by allergic reactions.
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Indications: Fexofenadine is indicated for the relief of symptoms associated with allergic rhinitis (both seasonal and perennial) and chronic idiopathic urticaria in adults and children aged 6 years and older. It is used to alleviate symptoms such as nasal congestion, sneezing, itching, runny nose, watery eyes, and skin rash or hives.
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Dosage and Administration: The usual dosage of fexofenadine for adults and children aged 12 years and older is 60 mg taken orally twice daily or 180 mg taken orally once daily. For children aged 6 to 11 years, the recommended dosage varies based on weight and is typically administered as a syrup or tablet formulation. Fexofenadine is typically taken with water, with or without food.
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Onset and Duration of Action: Fexofenadine has a relatively rapid onset of action, with symptom relief typically occurring within 1 to 3 hours after administration. The duration of action is generally 24 hours per dose, allowing for once-daily dosing for sustained relief of allergic symptoms.
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Safety and Side Effects: Fexofenadine is generally well-tolerated when used at recommended doses. It has a lower incidence of sedation and central nervous system (CNS) side effects compared to first-generation antihistamines. Common side effects may include headache, drowsiness, dry mouth, fatigue, and gastrointestinal symptoms such as nausea or abdominal pain.
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Contraindications: Fexofenadine is contraindicated in individuals with hypersensitivity to the active substance or any of the excipients in the formulation. It should not be used in patients with severe renal impairment (creatinine clearance < 10 mL/min) or end-stage renal disease requiring dialysis.
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Special Populations: Fexofenadine is considered safe for use in elderly patients and those with mild to moderate renal impairment. However, dosage adjustments may be necessary in these populations based on individual patient factors.