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Telfast (fexofenadine HCl, antihistamine)

Written by Stephanie Nera, RPh, PharmD · Pharmacology

Updated Jun 06, 2021

Telfast is the brand name of the drug fexofenadine. Fexofenadine is an antihistamine which works by blocking histamine in the body, preventing symptoms of allergies.

Know the basics

What is Telfast used for?

It is commonly used for dealing with seasonal allergy symptoms such as sneezing, runny nose, itchy throat, or itchy, watery eyes. It is also used to treat hives and skin rashes.

This drug may also be used for other conditions, as determined by your doctor.

How should I take Telfast?

  • Take fexofenadine by mouth with or without food, with a full glass of water. 
  • Do not consume other liquids aside from water when taking this medicine. (e.g. juice, milk, alcohol)
  • Avoid taking antacids that contain aluminum or magnesium at the same time as fexofenadine. You can take the antacid 2 to 4 hours before or after taking Telfast.

How do I store Telfast?

This product  is best stored at room temperature away from direct light and moisture. To prevent drug damage, you should not store it  in the bathroom or the freezer. There may be different brands of  this drug  that may have different storage needs. It is important to always check the product package for instructions on storage, or ask your pharmacist. For safety, you should keep all medicines away from children and pets.

You should not flush  this drug  down the toilet or pour them into a drain unless instructed to do so. It is important to properly discard this product when it is expired or no longer needed. Consult your pharmacist for more details about how to safely discard your product.

Precautions & warnings

What should I know before using Telfast?

Before using  this drug , you should talk to doctor if you are/have:

  • An allergy to any ingredient in this product
  • Kidney disease or troubles with urination
  • Pregnant, planning to become pregnant, or are breastfeeding
  • Taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement

Is it safe during pregnancy or breastfeeding?

There are no adequate studies in women for determining risk when using Telfast during pregnancy or while breastfeeding. Please always consult with your doctor to weigh the potential benefits and risks before taking this drug.

This drug is pregnancy risk category C according to the US Food and Drug Administration (FDA).

FDA pregnancy risk category reference below:

  • A=No risk
  • B=No risk in some studies
  • C=There may be some risk
  • D=Positive evidence of risk
  • X=Contraindicated
  • N=Unknown

Know the side effects

What side effects can occur from Telfast?

Major side effects

  • Chest tightness
  • Feeling of warmth, redness of the face, neck, arms and occasionally, upper chest
  • Swelling on face, eyelids, lips, tongue, throat, hands, legs, feet, or genitals
  • Shortness of breath, difficult or labored breathing

Minor side effects

  • Vomiting, diarrhea
  • Body aches or pain, back pain, joint pain, muscle aching or cramping
  • Muscle pains or stiffness
  • Difficulty with moving, dizziness
  • Ear congestion, earache, loss of voice
  • Fever, chills, coughing, headache, and nausea
  • Nasal congestion

Not everyone experiences these side effects. Additionally, there may be other side effects not listed above. If you have any concerns about a side effect, please consult your doctor or pharmacist.

Know the interactions

What drugs may interact with Telfast?

This drug may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects. To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, nonprescription drugs, and herbal products) and share it with your doctor and pharmacist.

For your safety, do not start, stop, or change the dosage of any drugs without your doctor’s approval.

  • Erythromycin or ketoconazole has been found to result in a 2-3 times increase in the level of Telfast in plasma.
  • The administration of an antacid containing aluminum and magnesium hydroxide gels 15 minutes prior to Telfast can reduce the availability of this drug.
  • Does food or alcohol interact with Telfast?

    This drug may interact with food or alcohol by altering the way the drug works or increase the risk for serious side effects. Do not take this drug with fruit juice or alcohol. Alcohol may induce excessive sleepiness and sedation.

    Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.

    What health conditions may interact with Telfast?

    Telfast may interact with other diseases or conditions. This interaction may worsen your health condition or alter the way the drug works. It is important to always let your doctor and pharmacist know all the health conditions you currently have, including:

    • Kidney or liver impairment
    • Cardiovascular disease

    Understanding the dose

    The information provided is not a substitute for any medical advice. Therefore, you should always consult with your doctor or pharmacist before using any medication .

    What is the dose for an adult?

    Seasonal Allergic Rhinitis/Chronic hives

    Oral route: 60 mg twice a day or 180 mg once a day.

    What is the dose for a child?

    Seasonal Allergic Rhinitis

    Oral route:

    • <2 years: use not recommended;
    • 2-12 years: 30 mg twice a day;
    • >12 years: 60 mg twice a day or 180 mg once a day.

    Chronic hives

    • <6 months: use not recommended;
    • 6 months-2 years: 15 mg twice a day;
    • 2-12 years: 30 mg twice a day;
    • >12 years: 60 mg twice a day or 180 mg once a day.

    How is Telfast available?

    Telfast is available in the following dosage forms and strengths:

    • Oral tablets 60mg, 120mg, 180mg

    What should I do in case of an emergency or overdose?

    In case of an emergency or an overdose, call your local emergency services or go to the nearest emergency room.

    What should I do if I miss a dose?

    If you miss a dose, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.


    Hello Health Group does not provide medical advice, diagnosis or treatment.

    Written by

    Stephanie Nera, RPh, PharmD


    Updated Jun 06, 2021

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