Fexofenadine (Telfast, Allegra) is a second-generation antihistamine that is used to treat patients with symptoms of allergy such as flu, sneezing, itching, and urticaria.

Fexofenadine (Telfast) Uses:

• Upper respiratory allergies:

  • Relief from hay fever or other upper respiratory allergens that causes runny noses, throat irritation, and/or itchy, watery eyes.

• Off Label Use of Fexofenadine in Adults:

  • Chronic idiopathic urticaria

Also Read: Loratadine (Alavert); Use, Side effects, Dosage

Fexofenadine (Telfast) Dose in Adults

Fexofenadine (Telfast) Dose in the treatment of Upper respiratory allergies: Oral:

• Formulations for use twice daily: 60 mg per 12 hours (up to 120 mg per day).
• Formulations to be taken once daily: 180 mg once daily (up to 180 mg per day).

Fexofenadine (Telfast) Dose in the treatment of Chronic idiopathic urticaria (off-label):

• Oral: 180 mg once in a day or
• 60 mg twice a day
• Range: 20 to 240 mg two times in day.

Fexofenadine (Telfast) Dose in Children

Fexofenadine (Telfast) Dose in the treatment of Allergic symptoms/rhinitis: Oral:

• Infants 6 months or more than 6 months and <10.5 kg:

  • Oral suspension: 15 mg twice in a day.
  • Dosing from a safety and tolerability study of infants with allergic rhinitis (n=58; mean age: 8.8 ± 1.6 months); adverse events were similar compared to placebo.
  • Note: Five patients received 30 mg twice daily, which also had similar adverse effects compared to placebo.

• Children 2 years or less than 2 years and  less than10.5 kg: Limited data available:

  • Oral suspension: 15 to 30 mg two times a day.
  • Dosing from a safety and tolerability study of patients with allergic rhinitis receiving fexofenadine 15 mg two times in a day (n= 27; mean age: 16.1 months) or fexofenadine 30 mg two times in a day(n=103; mean age: 17.9 ± 3.2 months) compared to placebo.
  • Adverse events were similar between patients receiving fexofenadine and patients receiving placebo (Hampell 2007).

• Children 2 to 11 years:

  • Oral suspension or orally disintegrating tablet (ODT):
    • 30 mg two times a day.

• Children ≥12 years and Adolescents:

  • Tablets, orally disintegrating tablet (ODT):
    • 60 mg two times in a day.
  • Extended-release tablet:
    • 180 mg once in a day.

Fexofenadine (Telfast) Dose in the treatment of Chronic idiopathic urticaria:

Note: Dosing based on previous FDA approved manufacturer labeling (Allegra prescribing information 2007): Oral:

• Infants ≥6 months to Children <2 years:

  • Oral suspension: 15 mg two times in a day.

• Children 2 to 11 years:

  • Oral suspension or orally disintegrating tablet (ODT):
    • 30 mg two times a day.

• Children ≥12 years and Adolescents:

  • Tablets, orally disintegrating tablet (ODT):
    • 60 mg two times a day.
  • Extended-release tablet:
    • 180 mg once in a day.

Fexofenadine pregnancy Risk Category: C

• There is limited information available about the pregnancy use of fexofenadine.
• Other agents that have more information about their use during pregnancy are preferred when a second-generation antihistamine becomes necessary.

Fexofenadine use during breastfeeding:

• We have not found information specific to breastfeeding and fexofenadine.
• After breastfeeding mothers have given terfenadine to their parent compound, fexofenadine was added to breast milk.
• Breastfeeding women may need to be treated with antihistamines. Second-generation antihistamines are more suitable for this population.
• Breastfed infants who were exposed to antihistamines have reported irritability and drowsiness. Infants exposed to terfenadine, the parent compound of fexofenadine, reported only irritability.
• Second-generation antihistamines tend to be less sedating than their first-generation counterparts.

Fexofenadine (Telfast) Dose in Kidney Disease:

• No dosage adjustment provide, except following (Aronoff 2007):
  • GFR >50 mL/minute:
    • No dosage adjustment necessary for twice in a day dosing (ie, 60 mg every 12 hours).
  • GFR 10 to 50 mL/minute:
    • 12 to 24 hours dose is recommended.
  • GFR <10 mL/minute:
    • Every 24 hours dose is recomended.
  • Intermittent hemodialysis or peritoneal dialysis:
    • Recommended dose every 24 hours.
  • Continuous renal replacement therapy (CRRT):
    • 60 mg every 24 hours.

Fexofenadine (Telfast) Dose in Liver disease:

No dosage adjustments.

Common Side Effects of Fexofenadine (Telfast):

• Central nervous system:

  • Headache

• Gastrointestinal:

  • Vomiting

Less Common Side Effects of Fexofenadine (Telfast):

• Central Nervous System:

  • Fatigue
  • Dizziness
  • Drowsiness
  • Pain

• Gastrointestinal:

  • Nausea
  • Dyspepsia
  • Diarrhea

• Genitourinary:

  • Dysmenorrhea

• Infection:

  • Viral Infection

• Neuromuscular & Skeletal:

  • Back Pain
  • Limb Pain
  • Myalgia

• Otic:

  • Otitis Media

• Respiratory:

  • Cough
  • Rhinorrhea
  • Upper Respiratory Tract Infection

• Miscellaneous:

  • Fever

Contraindications to Fexofenadine (Telfast):

OTC labeling

• Do not use this medication for self-medication if you have ever had an adverse reaction to fexofenadine or any other ingredient.

Warnings and precautions

• Renal impairment

  • Patients with impaired renal function should be cautious. Dosage adjustment may be necessary.

Fexofenadine: Drug Interaction

Note: Drug Interaction Categories:

• Risk Factor C: Monitor When Using Combination
• Risk Factor D: Consider Treatment Modification
• Risk Factor X: Avoid Concomitant Use

Monitoring parameters:

Relief of symptoms

How to administer Fexofenadine (Telfast)?

Orally disintegrating tablet:

• Administer when fasting.
• The tablet will dissolve with or without water if you take it out of the individual blister and place it right away on your tongue (do not administer with fruit juices).

Oral suspension, tablet:

• Do not administer with fruit juices; always administer with water.
• Before use, thoroughly shake the suspension. Use the provided dosage cup exclusively for suspension.

Mechanism of action of Fexofenadine (Telfast):

• Terfenadine has an active metabolite called fexofenadine.
• The search for H-1 receptor sites on effector cells of the gastrointestinal tract, blood arteries, and respiratory tract involves a competition with histamine.
• Fexofenadine doesn't appear to significantly cross the blood-brain barrier, which translates in a lesser risk of sedation.

The onset of action:

• 2 hours

Duration of action:

• 24 hours

Absorption:

• Rapid

Protein binding:

• 60% to 70%;
• primarily albumin and alpha -acid glycoprotein

Metabolism:

• Minimal (hepatic: 5%); 3.6% converted into a methyl ester metabolite that is only present in faeces

Bioavailability:

• ~33 percent

Half-life elimination:

• 14.4 hours (or 72% longer in patients with severe renal impairment [CrCl 11 to 40 mL/minute]; mild to moderate renal impairment [CrCl 41 to 80 mL/minute] people).

Time to peak, serum:

• ODT:
  • • 2 hours (4 hours with high-fat meal);
•  Tablet:
  • ~2.6 hours.
• Suspension:
  • ~1 hour

Excretion:

• Feces (80%) and urine (12%) as unchanged drug.

International Brand Names of Fexofenadine:

• Alertam
• Alexia
• Allegra
• Allegra 180
• Allegra Allergy
• Allegratab
• Allemax
• Allerex
• Altifex
• Altiva
• Avafast
• Bosnum
• Bosnum 180
• Delaxin
• Ewofex
• Exofen
• Fastel
• Fe Min
• Fenadex
• Fenadin
• Fenafex
• Fexet
• Fexodex
• Fexodine
• Fexofast
• Fexofen
• Fexon
• Allegra Allergy Childrens
• Allegra Allergy
• Allergy 24-HR
• Allergy Relief
• Fexofenadine HCl Childrens
• Mucinex Allergy
• Alagra
• Alanil
• Alerfedine
• Fexoral
• Fexotabs
• Fexotene
• Fexovid
• Fynadin
• Inflex
• Kofixir
• Nasaga
• Neofex
• Raltiva
• Rhinogan
• Ritch
• Sizzle
• SkyFexo
• Tefodine
• Telfast
• Telfast HD
• Telfast OD
• Telfast Oral Solution
• Telfor
• Ternafast
• Tocimat
• Tofexo
• Vifas
• Xadine
• Xergic
• Xofast

Fexofenadine Brand Names in Pakistan: