Anxiety, palpitations, insomnia, mild GI distubances, erythema multiforme and galactorrhoea.
Potentially Fatal: Ventricular arrhythmias including torsades de pointes. Palpitations, dizziness, syncope or convulsions may indicate arrhythmias. Hepatitis.
Absorption: Rapidly absorbed from GI tract. Peak plasma concentrations: within 2 hr. Distribution: Protein binding: 97% (terfenadine). Does not appear to cross the blood-brain barrier to significant extent. Limited amounts of fexofenadine, but not terfenadine detected in breast milk.
Elimination Half-life: 16-23 hr (terfenadine). Metabolism: Prodrug and undergoes extensive first-pass metabolism in the liver to active (carboxylic acid derivative fexofenadine) and inactive metabolites. Excretion: Excreted in the urine and faeces (traces of unchanged drug and metabolites)