Telfast

Antiallergic , Drugs / September 22, 2016

Class: Antiallergic
Dosage Form: Tablets
Description: Antihistaminic and antiallergic
Stock: Available
Manufacturer: Sanofi Aventis

Composition:

Active Ingredient
Fexofenadine hydrochloride…………………….120 and 180 mg
Excipients
Tablet coat: Microcrstalline cellulose, pregelatinized maize starch, croscaramellose sodium, magnesium stearate.
Film coat: Hypromellose, povidone, titanium dioxide (E171), collodial anhydrous silica, macrogol 400, iron oxide red (E172) and iron oxide yellow (E172).

Properties:

Pharmacodynamics
Fexofenadine hydrochloride is a non-sedating H1-antihistame. Fexofenadine is a pharamcologically active metabolite of terfenadine.
Human histamine wheal and flare studies following single and twice daily doses of fexofenadine hydrochloride demonstrate that:

  • The drug exhibits an antihistaminic effect beginning within one hour, acheiving a maximum at 6 hours and lasting 24 hours
  • There was no evidence of tolerance to these effects after 28 days of dosing
  • A positive dose-response relationship between doses of 10 mg to 130 mg taken orally was found to exist
  • Doses of at least 130 mg were required to achieve a consistent effect that was maintained over a 24 hour period
  • Maximum inhibition in skin wheal and flare areas were greater than 80%

Clinical studies conducted in seasonal allergic rhinitis have shown that:

  • A dose of 120 mg is sufficient for 24 hour efficacy
  • No significant differences in QTc intervals where observed in patients given fexofenadine hydrochloride up to 240 mg twice daily for 2 weeks when compared to placebo. Fexofenadine at concentrations 32 times greater than the therapeutic concentration in man had no effect on the delayed rectifier K+ channel cloned from human heart

Pharmacokinetics

  • Fexofenadine hydrochloride is rapidly absorbed into the body following oral administration, with Tmax occuring at approximately 1-3 hours post dose. The mean Cmax value was approximately 427 ng/ml follwing the administration of a 120 mg dose once daily
  • Fexofenadine is 60-70% plasma protein bound
  • Fexofenadine undergoes negligible metabloism (hepatic or non-hepatic), as it was the only major compound indentified in urine and faeces of animals and man
  • The plasma concentration profiles of fexofenadine follow a bi-exponential decline with a terminal elimination half-life raning from 11 to 15 hours afer multiple dosing. The single and multiple dose pharmacokinetics of fexofenadine are linear for oral doses up to 120 mg BID. A dose of 240 mg BID produced slightly greater than proportional increase (8.8%) in steady state area under the curve, indicating that fexofenadine pharmacokinetics is pracitcally linear at these doses between 40 mg and 240 mg taken daily
  • The major routeĀ  of elimination is believed to be via biliary excretion while up to 10% of ingested dose is excreted unchanged through the urine

Indications:

Telfast 120 is indicated in:

  • Relief of symptoms associated with seasonal allergic rhinitis, ex: sneezing, rhinorrhea, itch or watery red eyes, itchy nose, throat or pallate and nasal congestion

Telfast 180 is indicated in:

  • Relief of symptoms associated with chronic idiopathic urticaria, ex: wheal, flare and pruritus

Contraindicatons:

Patients with known hypersensitivity to any of the ingredients.

Drug Interactions:

Telfast is contraindicated in:

  • Coadministration of fexofenadine hydrochloried with erythromycin or ketoconazole has been found to result in a 2-3 times increase in level of fexofenadine in plasma. The changes were not accompanied by any effects on the QT interval and were not associated with any increase in adverse events compared to the drugs given singly.
  • Animal studies have shown that the increase in plasma levels of fexofenadine observed after coadministration of erythromycin or ketoconazole, appears to be due to an increase in gastrointestinal absorption and either a decrease in biliary excertion or gastrointestinal secretion, respectively.
  • No interaction between fexofenadine and omeprazole was observed. However, the administration of an antacid, containing aluminum and magnesium hydroxide gels, 15 minutes prior to fexofenadine hydrochloride caused a reduction in bioavailability. Hence it is advisable to leave 2 hours in between administration of fexofenadine hydrochloride and aluminium and magnesium hydroxide containing antacids.
  • Fexofenadine does not undergo hepatic biotransformation and thus will not interact with other drugs through hepatic mechanisms.

Side Effects:

In controlled clinical trial the most commonly reported adverse events were headaches (7.3%), drowsiness (2.3%), nausea (1.5%), dizziness (1.5%) and fatigue (0.9%).
The incidence of these events observed with fexofenadine was similar to that observed with placebo.
In rare cases, rash, urticaria, pruritus, and hypersensitvity reactions with manifestations such as angiodema, chest tightness, dyspnea, flushing and systemic anaphylaxis have been reported.

Dosage and Administration:

1.Adults and children aged 12 years and over:

  • Recommended dose for those with seasonal allergic rhinitis is 120 mg once daily
  • Recommended dose for those with chronic idiopathic urticaria is 180 mg once daily

2. Children under 12 years of age:

  • Special formulations and dose is under development

3. Special risk groups:

  • Studies in special risk groups (elderly, renally or hepatically impaired patients) indicate that it is not necessary to adjust the dose of fexofenadine hydrochloride in these patients

Overdosage:

There has been no reported case of an acute overdosage of fexofenadine hydrochloride. In case of overdose, standard measures should be considered to remove any unabsorbed drug.
Hemodialysis does not effectively remove fexofenadine hydrochloride from blood.

Pregnancy and Lactation:

There is no experience with fexofenadine hydrochloride in pregnant women. As with other medications, fexofenadine hydrochloride should not be used during pregnancy unless the expected benefit to the patient outweighs any possible risk to the fetus.
There are no data on the content of the human milk after administering fexofenadine hydrochloride. However, when terfenadine was administered to nursing mothers, fexofenadine was found to cross into human breast milk. Therefore, fexofenadine hydrochloride is not recommended for nursing mothers.

Warnings:

As with most new drugs, there is only limited data in the elderly, renally or hepatically impaired patients. Fexofenadine should be administered with care in these patients’ groups.
Patients may drive or perform tasks that require concentration. However, in order to identify sensitive people who have an unusual reaction to drugs, it is advisable to check the individual response before driving or performing complicated tasks.
On the basis of the pharmacodynamic profile and reported adverse events, it is unlikely that fexofenadine hydrochloride tablets will produce an effect on the ability to drive or use machines. In objective tests, Telfast has been shown to have no significant effects on central nervous system function.

Packaging:

Pack of 2 strips of 10 tablets each.

Storage:

Store at room temperature, away from light and moisture.

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