HISTAFIX

Each film coated tablets contains:
(Fexofenadine Hydrochloride USP 120 mg / 180 mg)

Tablet for Oral Use

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. Fexofenadine does not cross the blood-brain barrier and thus is unlikely to cause significant CNS effects.

Absorption: Fexofenadine is rapidly absorbed, attaining peak plasma concentrations one hour after oral administration at 1 hour for the oral suspension and 1.5 hours for the tablet. Maximum histamine inhibition is achieved approximately 1–2 h after administration.

Distribution: Fexofenadine has approximately 60% to 70% plasma protein binding. Fexofenadine binds primarily with albumin and alpha-1 acid glycoprotein. Fexofenadine shows no receptor occupancy in the CNS at clinically relevant doses.

Metabolism &Excretion: Fexofenadine undergoes minimal hepatic metabolism. Fexofenadine is mainly excreted in feces via biliary excretion (80%).

Half Life: In healthy volunteers, the mean elimination half-life is approximately 14.4 hours after administering fexofenadine 60 mg twice.

• Seasonal allergic rhinitis characterized by symptoms including nasal itching, sneezing, rhinorrhea, and nasal congestion
• Chronic idiopathic urticaria
• Hives

ADVERSE EFFECTS: The most frequently occurring side effects are drowsiness, fatigue, and dry mouth, which may occur in larger doses.

DOSAGE AND ADMINISTRATION: One tablet once daily

CONTRAINDICATIONS:

• Hypersensitivity to fexofenadine or any of its components is the only true contraindication to this medication’s use

WARNINGS AND PRECAUTIONS

• Caution is necessary when treating patients with renal disease
• There is no significant interaction with fexofenadine and concomitant use of alcohol or food. However, bioavailability decreases when used with grapefruit, apple, or orange juice
• In animal models, fexofenadine has been shown to cause low birth weight and is currently a category C medication in pregnancy. Alternatives for symptom relief of allergic rhinitis include Loratadine and Cetirizine
• Fexofenadine might decrease milk production, especially if used with pseudoephedrine. While breastfeeding an infant, monitor for possible irritability and jitteriness

Pregnancy Category: C

Drug Interaction:

• Betahistine can decrease the therapeutic potential of fexofenadine
• Pilolisant is a histamine-3 receptor antagonist and inverse agonist approved for narcolepsy. Concurrent use of antihistamines should be avoided.
• Concurrent administration of Apalutamide with Fexofenadine, decreases the AUC of Fexofenadine by 30%, which may result in loss of efficacy of Fexofenadine.