Fexofenadine
Mechanism :
Fexofenadine hydrochloride, the major active metabolite of terfenadine, is an antihistamine with selective peripheral H1-receptor antagonist activity. Both enantiomers of fexofenadine hydrochloride displayed approximately equipotent antihistaminic effects.
Indication :
- Chronic idiopathic urticaria
- Seasonal allergic rhinitis
Contraindications :
Contraindicated in patients with known hypersensitivity to it or its inactive ingredients.
Dosing :
Chronic idiopathic urticaria:
Under 6 months:
Use not recommended.
6 months-2 years:
15 mg orally twice daily.
2-12 years:
30 mg orally twice daily.
Above 12 years:
60 mg orally twice daily OR 180 mg orally once daily.
Seasonal Allergic Rhinitis:
Under 2 years:
Use not recommended.
2-12 years:
30 mg orally twice daily.
Above 12 years:
60 mg orally twice daily OR 180 mg orally once daily.
Adverse Effect :
Insomnia, dizziness, flatulence, diarrhea, abdominal pain, dyspepsia, vomiting, epistaxis, throat irritation, nervousness, appetite increase, agitation, nightmares, dry mouth, dryness of mucous membranes, thirst, urinary frequency, earache, chest pain, pruritus, rash, blurred vision, tachycardia, palpitation.
Interaction :
Since fexofenadine does not undergo hepatic biotransformation, it is unlikely to interact with drugs that rely upon hepatic metabolism.
Erythromycin and Ketoconazole: Increase the plasma levels of fexofenadine two- to three-fold.
Antacids containing Aluminium or Magnesium: Reduce the absorption of fexofenadine.
Renal Dose :
Dose in Renal Impairment GFR (mL/min)
| 20-50 | Dose as in normal renal function. Use with care |
| 10-20 | Initial dose 60 mg once or twice daily. |
| <10 | Initial dose 60 mg once daily. |
Dose in Patients undergoing Renal Replacement Therapies
| CAPD | Unlikely dialysability. Dose as in GFR<10 mL/min |
| HD | Not dialysed. Dose as in GFR<10 mL/min |
| HDF/High flux | Unknown dialysability. Dose as in GFR<10 mL/min |
| CAV/VVHD | Unlikely to be dialysed. Dose as in GFR=10–20 mL/min |
Hepatic Dose :
No dosage adjustment is recommended.