Fexofenadine

Brand names: Allegra®

Chemical formula:

Drug Forms:
• Fexofenadine oral suspension (below)
• Fexofenadine orally disintegrating tablets
• Fexofenadine Hydrochloride Oral capsule
• Fexofenadine Hydrochloride Oral disintegrating tablet
• Fexofenadine Hydrochloride Oral suspension
• Fexofenadine Hydrochloride Oral tablet

Español:
• Fexofenadina Clorhidrato, Cápsula oral
• Clorhidrato de fexofenadina, Tableta que se desintegra por vía oral
• Clorhidrato de fexofenadina, Suspensión oral
• Fexofenadina Clorhidrato, Tableta oral

Fexofenadine oral suspension

What is Fexofenadine oral suspension?

FEXOFENADINE (Allegra) is an antihistamine. It reduces allergy symptoms of hay fever (seasonal allergic rhinitis), and may reduce itching of the skin in people with chronic itchy skin rashes.

What should I tell my health care provider before I take this medicine?

They need to know if you have any of these conditions:
• kidney disease
• an unusual or allergic reaction to fexofenadine, terfenadine, other medicines, foods, dyes, or preservatives
• pregnant or trying to get pregnant
• breast-feeding

How should this medicine be used?

Shake the bottle well before each use. Do not take this medicine with grapefruit, orange, or apple juice because they may change how well the medicine works. You may take this medicine with food. Use a specially marked spoon or container to measure your medicine. Ask your pharmacist if you do not have one; household spoons are not accurate. Follow the directions on the prescription label. Take your doses at regular intervals. Do not take your medicine more often than directed. You may need to take it for several days as prescribed before your symptoms improve.

Contact your pediatrician or health care professional regarding the use of this medicine in children. While this drug may be prescribed for children as young as 6 months for selected conditions, precautions do apply.

What drug(s) may interact with Fexofenadine?

• antacids
• erythromycin
• grapefruit, apple, or orange juice
• ketoconazole
• rifampin
• St. John's Wort

In addition, the following medicines can make you feel drowsy:
• alcohol
• barbiturate medicines for inducing sleep or treating seizures (convulsions)
• medicines for anxiety or sleeping problems, such as alprazolam, diazepam or temazepam
• medicines for hay fever and other allergies such as antihistamines
• medicines for mental depression (antidepressants)
• medicines for mental problems, anxieties and psychotic disturbances
• medicines for pain such as opiate analgesics (e.g., codeine)

Tell your prescriber or health care professional about all other medicines you are taking, including non-prescription medicines, nutritional supplements, or herbal products. Also tell your prescriber or health care professional if you are a frequent user of drinks with caffeine or alcohol, if you smoke, or if you use illegal drugs. These may affect the way your medicine works. Check with your health care professional before stopping or starting any of your medicines.

What should I watch for while taking Fexofenadine?

Tell your prescriber or health care professional if your symptoms do not improve in 1 or 2 days.

This medicine causes less drowsiness than most other antihistamines. Until you know if it makes you drowsy or dizzy, do not drive, use machinery, or do anything that needs mental alertness.

Do not sit or stand up quickly, especially if you are an older patient. This reduces the risk of dizzy or fainting spells.

What side effects may I notice from receiving Fexofenadine?

Side effects that you should report to your prescriber or health care professional as soon as possible:
• cough
• infection or fever

Side effects that usually do not require medical attention (report to your prescriber or health care professional if they continue or are bothersome):
• dizziness
• headache
• menstrual changes
• muscle pain
• stomach upset, nausea, vomiting
• tiredness or drowsiness

Where can I keep my medicine?

Keep out of the reach of children in a tightly closed container that small children cannot open.

Store at room temperature between 20 and 25 degrees C (68 and 77 degrees F). Keep in a cool, dry place. Throw away any unused medicine after the expiration date.

Last updated: 7/1/2002

Important Disclaimer: The drug information provided here is for educational purposes only. It is intended to supplement, not substitute for, the diagnosis, treatment and advice of a medical professional. This drug information does not cover all possible uses, precautions, side effects and interactions. It should not be construed to indicate that this or any drug is safe for you. Consult your medical professional for guidance before using any prescription or over the counter drugs.

Fexofenadine

Systematic (IUPAC) name
(RS)-2-[4-[1-hydroxy-4-[4-(hydroxy-diphenyl- methyl)-1-piperidyl]butyl]phenyl]-2- methyl-propanoic acid
Identifiers
CAS number	83799-24-0
ATC code	R06A626
PubChem	?
ChemSpider	3231
Chemical data
Formula	C32H39NO4
Mol. mass	501.656
SMILES	eMolecules & PubChem
Pharmacokinetic data
Bioavailability	Not yet established
Protein binding	60-70%
Metabolism	Hepatic (5% of dose)
Half life	14.4 hours
Excretion	Feces (~80%) and urine (~11%) as unchanged drug
Therapeutic considerations
Pregnancy cat.	C (US) B2 (Australia)
Legal status	Prescription Only (US, UK) OTC (Canada, Australia)
Routes	Oral
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Fexofenadine (Allegra, Telfast, Fastofen, Tilfur) is an antihistamine drug used in the treatment of hayfever and similar allergy symptoms. It was developed as a successor of and alternative to terfenadine (brand names include Triludan and Seldane), an antihistamine with potentially serious contraindications. Fexofenadine, like other second and third-generation antihistamines, does not readily cross the blood-brain barrier, and so causes less drowsiness than first-generation histamine-receptor antagonists. It works by being an antagonist to the H₁ receptor.^[1]

It has been described as both second-generation^[2] and third-generation.^[3]

Contents 1 Indications 2 Dosage 3 Administration 4 Dosage forms 5 Common side effects 6 Overdose 7 History 8 Synthesis 9 Notes 10 References 11 External links

Indications

Fexofenadine is indicated for the relief from physical symptoms associated with seasonal allergic rhinitis and treatment of chronic idiopathic urticaria. It is not a therapeutic drug and does not cure but rather prevents the aggravation of rhinitis and urticaria and reduces the severity of the symptoms providing much relief from repeated sneezing, runny nose, itchy eyes and general body fatigue caused by rhinitis and urticaria. It is a safe and easy to use drug available in doses of 120 and 180 mg to be taken once a day for at least 5 days or at least till the symptoms reduce in severity and impact

Dosage

• Chronic idiopathic urticaria: Children 6 months to < 2 years: 15 mg twice daily
• Chronic idiopathic urticaria, seasonal allergic rhinitis:
  • Children 2–11 years: 30 mg twice daily
  • Children ≥ 12 years and Adult: 60 mg twice daily or 180 mg once daily
  • Elderly: Starting dose: 60 mg once daily;

Administration

Administer with water only; do not administer with fruit juices. Shake suspension well before use.

Dosage forms

• Suspension: 6 mg/mL (30 mL, 300 mL) [raspberry cream]
• Tablet: 30 mg, 60 mg, 180 mg

Common side effects

• Nausea
• Dizziness
• Vomiting
• Weakness
• Drowsiness, sleepiness
• Fatigue
• Diarrhea
• Unusual bowel movements
• Headache

Overdose

Reports of fexofenadine overdose are infrequent, and because of this, the effects are not well established. No deaths occurred in testing on mice, at 5000 mg/kg, which is 110 times the maximum recommended dose for an adult human. Further research shows no deaths in rats at the same concentration, which equates four hundred times the recommended dose in an adult human. Research on humans ranges from a single 800 mg dose, to a twice-daily 690 mg dose for a month, with no clinically significant adverse effects, when compared to a placebo.

History

The older antihistaminic agent terfenadine was found to metabolize into the related carboxylic acid, fexofenadine. Fexofenadine was found to retain all of the biological activity of its parent while giving fewer adverse reactions in patients, so terfenadine was replaced in the market by its metabolite.^[4] Fexofenadine was originally synthesized in 1993 by Massachusetts-based biotechnology company Sepracor, which then sold the development rights to Hoechst Marion Roussel (now part of Sanofi-Aventis), and was later approved by the Food and Drug Administration (FDA) in 1996. AMRI holds the patents to the intermediates and production of fexofenadine HCl along with Roussel. Since that time, it has achieved blockbuster drug status with global sales of $1.87B USD in 2004 (with $1.49B USD coming from the United States). AMRI received royalty payments from Aventis that enabled the growth of AMRI.

Synthesis

Fexofenadine may be synthesized as shown from piperidine-4-carboxylate ester and 4-bromophenylacetonitrile.^[4]

To produce the piperidine piece, two phenyl groups are first introduced using a Grignard reaction on the ester, giving a tertiary alcohol. The amine group is then alkylated with a protected aldehyde, then the aldehyde is recovered by deprotection with acid. The remaining piece of the molecule is produced by a double alkylation by iodomethane of the carbanion derived from the nitrile. The nitrile group is then hydrolyzed to a carboxylic acid. The aryl bromide is then lithiated to produce the organolithium compound, which can be coupled with the aldehyde piece to give (after workup) fexofenadine.

Notes

1. ^ IngentaConnect - Fexofenadine, an H1-receptor antagonist, partially ...
2. ^ Dicpinigaitis PV, Gayle YE (November 2003). "Effect of the second-generation antihistamine, fexofenadine, on cough reflex sensitivity and pulmonary function". British journal of clinical pharmacology 56 (5): 501–4. PMID 14651723. PMC 1884387. http://www.blackwell-synergy.com/openurl?genre=article&sid=nlm:pubmed&issn=0306-5251&date=2003&volume=56&issue=5&spage=501. 
3. ^ Vena GA, Cassano N, Filieri M, Filotico R, D'Argento V, Coviello C (2002). "Fexofenadine in chronic idiopathic urticaria: a clinical and immunohistochemical evaluation". International journal of immunopathology and pharmacology 15 (3): 217–224. PMID 12575922. 
4. ^ ^{a b} Daniel Lednicer (1999). The Organic Chemistry of Drug Synthesis. 6. New York: Wiley Interscience. pp. 38–40. ISBN 0-471-24510-0. 

References

• Synthesis: J. Org. Chem. 1994, 59, 2620.
• Biological effects: Mol. Pharmacol. 1993, 44, 1240.

External links

• Fexofenadine (UK patient information leaflet)
• Allegra (Fexofenadine Hydrochloride) label and research information
• Sanofi-aventis (Home page)
• Fexofenadine (MedicineNet) (Written by Pharmacists; Reviewed by Doctors)

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