Telfast
Telfast Uses, Dosage, Side Effects, Food Interaction and all others data.
Telfast Hydrochloride is an antihistamine with selective peripheral H1 receptor antagonist activity. It inhibits histamine release from peritoneal mast cells. No anticholinergic, α-1 adrenergic or β-adrenergic receptor blocking effects has been observed. No sedative or other central nervous system effect has been observed. It does not appear to cross the blood brain barrier.
Telfast is rapidly absorbed after oral administration with peak plasma concentration being reached in 2-3 hours. Elimination half-life of about 14 hours has been reported although this may be prolonged in patients with renal impairment.
Telfast relieves allergy symptoms by antagonizing the actions of histamine, an endogenous compound predominantly responsible for allergic symptomatology. The relatively long duration of action of fexofenadine (approximately 24 hours) allows for once or twice daily dosing, and its rapid absorption allows for an onset of action within 1-3 hours. Telfast should not be taken with fruit juice, as this may impair its absorption.
| Trade Name | Telfast |
| Availability | Rx and/or OTC |
| Generic | Fexofenadine |
| Fexofenadine Other Names | Carboxyterfenadine, Fexofenadina, Fexofenadine, Terfenadine acid metabolite, Terfenadine carboxylate, Terfenadine-COOH |
| Related Drugs | prednisone, cetirizine, loratadine, fluticasone nasal, promethazine, diphenhydramine, Zyrtec, Xolair |
| Weight | 60mg, 120mg, 180mg, 30mg/5ml, |
| Type | Tablet, Oral Suspension, Film Coated, Film-coated Tablet |
| Formula | C32H39NO4 |
| Weight | Average: 501.6564 Monoisotopic: 501.287908741 |
| Protein binding | Fexofenadine is 60-70% bound to plasma proteins, primarily to albumin and α1-acid glycoprotein. The extent of protein binding is decreased to 56-68% and 56-75% in patients with renal and hepatic impairment, respectively. |
| Groups | Approved, Investigational |
| Therapeutic Class | Non-sedating antihistamines |
| Manufacturer | Sanofi Aventis (pakistan) Ltd, , Sanofi Bangladesh Ltd, Sanofi, Sanofi Winthrop Industrie, Sanofi Aventis France, Aventis Indonesia |
| Available Country | Pakistan, Bangladesh, United Kingdom, Australia, Saudi Arabia, Portugal, Spain, Switzerland, Indonesia, |
| Last Updated: | September 19, 2023 at 7:00 am |
Uses
It is used for the relief of symptoms associated with seasonal and perennial allergic rhinitis and chronic idiopathic urticaria.
Telfast is also used to associated treatment for these conditions: Allergic Rhinitis (AR), Chronic Idiopathic Urticaria, Seasonal Allergic Rhinitis, Antihistamine
How Telfast works
The H1 histamine receptor is responsible for mediating hypersensitivity and allergic reactions. Exposure to an allergen results in degranulation of mast cells and basophils, which then release histamine and other inflammatory mediators. Histamine binds to, and activates, H1 receptors, which results in the further release of pro-inflammatory cytokines, such as interleukins, from basophils and mast cells. These downstream effects of histamine binding are responsible for a wide variety of allergic symptoms, such as pruritus, rhinorrhea, and watery eyes.
Telfast is considered an “inverse agonist” of the H1 receptor because it binds to and stabilizes the inactive form of the receptor, preventing its activation and subsequent downstream effects. It has a potent and selective affinity for H1 receptors, and there is no evidence that it carries antidopaminergic, antiserotonergic, anticholinergic, sedative, or adrenergic blocking activity. Telfast does not cross the blood-brain barrier and thus is unlikely to cause significant CNS effects.
Dosage
Telfast dosage
Adults-
- Allergic rhinitis: 120 mg once daily or 60 mg twice daily
- Urticaria: 180 mg once daily
Children-
- 2-11 years: 30 mg (1 spoonful) or 5 ml twice daily
- 6 months-2 years: 15 mg (1/2 spoonful) or 2.5 ml twice daily
In case of decreased renal function, care should be taken in dose selection and it may be useful to monitor renal function.
Side Effects
Telfast is generally well tolerated. The most commonly reported adverse events are headache, drowsiness, nausea, and dizziness. The incidence of these events observed with Telfast hydrochloride was similar to that observed with placebo.
Toxicity
No deaths were observed following the oral administration of up to 5000 mg/kg in both mice and rats (equivalent to approximately 100-200x the recommended human dose). Single doses of up to 800 mg and chronic exposure of up to 690 mg twice daily for 1 month in humans did not result in clinically significant adverse events. Symptoms of overdosage are consistent with fexofenadine's adverse effect profile and are likely to include dizziness, drowsiness, and dry mouth.
If overdosage occurs, employ symptomatic and supportive treatment. Hemodialysis does not effectively remove fexofenadine from the blood and is therefore of no benefit.
Precaution
Studies in the elderly, patients with hepatic impairment and patients with cardiac disease exposed to Telfast showed no statistically significant differences compared to healthy individuals. As with most new drugs there is only limited data in the elderly and renally or hepatically impaired patients. Telfast hydrochloride should be administered with care in these special groups.
Interaction
Co-administration of Telfast Hydrochloride with either ketoconazole or erythromycin may cause increased plasma concentration of Telfast. Antacid containing Aluminium and Magnesium may reduce the absorption of Telfast. Fruit juices such as grapefruit, orange and apple may reduce the bioavailability of Telfast.
Food Interaction
- Avoid fruit juice. Fruit juices like grapefruit, orange, and apple may reduce bioavailability and overall exposure to the medication.
- Take with or without food. Co-administration with food does not significantly affect absorption.
[Moderate] GENERALLY AVOID: Coadministration with large amounts of certain fruit juices, including grapefruit, orange and apple, may decrease the oral bioavailability of fexofenadine.
The proposed mechanism is inhibition of drug efflux via intestinal organic anion transporting polypeptides (e.g., P-glycoprotein), of which fexofenadine is a substrate.
In a five-way crossover study with 10 healthy volunteers, 1<4-strength grapefruit juice, grapefruit juice, orange juice and apple juice (300 mL with drug administration and 150 mL every 1<2 hour for up to 3 hours, total volume 1.2 L) reduced the mean area under the plasma concentration-time curve (AUC) of a 120 mg dose of fexofenadine by 23%, 67%, 72% and 77%, respectively, compared to water.
Mean peak plasma concentration (Cmax) was similarly affected.
The clinical significance of these changes is unknown.
However, results from studies using histamine-induced skin wheals and flares found that the size of wheal and flare was significantly larger when fexofenadine was administered with either grapefruit or orange juices compared to water.
MANAGEMENT: To maximize plasma levels and therapeutic effects, fexofenadine should be taken with water.
In addition, patients should refrain from consuming large amounts of grapefruit, orange, or apple juice.
Telfast Drug Interaction
Unknown: aspirin, aspirin, diphenhydramine, diphenhydramine, duloxetine, duloxetine, omega-3 polyunsaturated fatty acids, omega-3 polyunsaturated fatty acids, fluticasone nasal, fluticasone nasal, esomeprazole, esomeprazole, montelukast, montelukast, cyanocobalamin, cyanocobalamin, ascorbic acid, ascorbic acid, cholecalciferol, cholecalciferol
Telfast Disease Interaction
Volume of Distribution
The volume of distribution is approximately 5.4-5.8 L/kg.
Elimination Route
Telfast is rapidly absorbed following oral administration and its absolute bioavailability is approximately 33%. The Tmax following oral administration is approximately 1-3 hours. The steady-state AUCss(0-12h) and Cmax following twice daily dosing of 60mg are 1367 ng/mL.h and 299 ng/mL, respectively.
Telfast AUC is decreased by >20% when coadministered with fruit juices (e.g. apple, orange, grapefruit) due to their inhibition of OATP transporters - for this reason, prescribing information recommends administering fexofenadine only with water. Similarly, coadministration of fexofenadine with a high-fat meal appears to decrease AUC and Cmax by >20%.
Half Life
The terminal elimination half-life is approximately 11-15 hours.
Clearance
The oral clearance of fexofenadine is approximately 50.6 L/h and the renal clearance is approximately 4.32 L/h.
Elimination Route
Approximately 80% of an ingested dose is eliminated in the feces, likely largely unchanged due to fexofenadine's limited metabolism, and 11% is eliminated in the urine. The principal pathways of fexofenadine elimination are biliary and renal.
Pregnancy & Breastfeeding use
Pregnancy Category B. There are no adequate and well controlled studies in pregnant women. Telfast should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Lactation: It is not known if Telfast is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when Telfast is administered to a nursing woman.
Contraindication
Telfast is contraindicated in patients with known hypersensitivity to Telfast or any of the ingredients of Telfast Hydrochloride.
Special Warning
Studies in special risk groups (elderly, renally or hepatically impaired patients) indicate that it is not necessary to adjust the dose of Telfast Hydrochloride in these patients.
Acute Overdose
In case of an overdose, standard measures to remove any unabsorbed drug should be employed. Symptomatic and supportive treatment is recommended. There has been no reported case of an acute overdose of Telfast hydrochloride.
Storage Condition
Store Telfast at controlled room temperature 20-25 °C. Keep all medicines away from reach of children.
Innovators Monograph
You find simplified version here Telfast
Telfast contains Fexofenadine see full prescribing information from innovator Telfast Monograph, Telfast MSDS, Telfast FDA label
FAQ
What is Telfast used to treat?
Telfast is an antihistamine medicine that helps with the symptoms of allergies. It's used to treat: hay fever. conjunctivitis (red, itchy eye)
When is it best to take Telfast?
You should take Telfast before a meal where possible. Some people find it helps to swallow the tablet with a drink of water. Try to take the tablets at the same time of day each day, as this will help you to remember to take them
Should Telfast be taken in the morning or at night?
If you are taking a 12 hour form of Telfast, it can be taken once in the morning and once in the evening. If you are taking an Telfast once-a-day 24 hour tablet, it can be taken at any time of the day.
Who should not take Telfast?
Ask a doctor before using this medicine if you are pregnant or breastfeeding. Older adults may be more sensitive to the effects of this medicine. If you are 65 or older, ask a doctor before taking Telfast. This medicine may contain phenylalanine.
Does Telfast raise blood pressure?
However, medicines containing decongestants including Telfast could increase your blood pressure and heart rate or interfere with your heart medication.
Can Telfast cause high cholesterol?
The low dose of cetirizine did not affect serum lipid levels. On the other hand, the low dose of Telfast significantly increased LDL cholesterol.
Can Telfast cause heart palpitations?
Telfast is often given chronically, at least during allergic season. Common side effects include blurred vision, dry mouth and throat, palpitations, tachycardia, abdominal distress, constipation and headache.
Can I take Telfast at night?
As well as taking a non-drowsy antihistamine during the day (such as Telfast, cetirizine or loratadine), your doctor may suggest that you take a sedating antihistamine at night time if the itching is making it difficult to sleep
How long does Telfast last?
This medicine starts to relieve your symptoms within 1 hour and lasts for 24 hours
Is Telfast safe to take pregnancy time?
Telfast use during pregnancy does not appear to be associated with a risk of adverse fetal outcomes; the results indicate that Telfast may have a fetal safety profile comparable to that of the currently recommended second-generation antihistamines during pregnancy.
Is Telfast safe for long term use?
Doses up to 240mg once daily for up to 12 months in healthy volunteers, is safe and well tolerated.
Can Telfast cause a sore throat?
Common side effects may include: headache, back pain,or cold symptoms such as stuffy nose, sinus pain, sore throat.
Does Telfast cause anxiety?
Many people using this medication do not have serious side effects. Tell your doctor right away if you have any serious side effects, including: fast/irregular/pounding heartbeat, shaking (tremor), mental/mood changes (such as anxiety, confusion, nervousness, restlessness), problems urinating.
Can Telfast cause chest pain?
Allergic reactions to the medicine, which may cause swelling of the face, lips, tongue or throat, difficulty breathing, chest tightness or flushing.
Is Telfast a stimulant?
Although antihistamines are known for their sedative adverse effects, Telfast was previously shown to have stimulating effects. These stimulant effects were rather mild in magnitude and were only demonstrated in tasks with a high workload.
How good is Telfast hydrochloride?
Telfast has an average rating of 6.3 out of 10 from a total of 149 ratings on Drugs.com. 56% of reviewers reported a positive effect, while 31% reported a negative effect.
Is it safe to take Telfast everyday?
May be given daily on a regular basis when allergens are most prevalent (such as during spring or summer). Telfast is approved for use in children older than 6 months with chronic urticaria and those older than two years with seasonal allergic rhinitis.
Is there anything stronger than Telfast?
Several studies have found cetirizine to be more effective than Telfast at relieving symptoms of allergic rhinitis and urticaria, and it appears to have a longer duration of action.
How long does Telfast take to work?
Telfast usually starts to work within half an hour to an hour after taking a dose.
How effective is Telfast?
Telfast was effective in relieving the symptoms of sneezing, rhinorrhoea, itchy nose palate or throat, and itchy, watery, red eyes in patients with seasonal allergic rhinitis. There were often small improvements in nasal congestion that were further improved by pseudoephedrine.
Can Telfast be cut in half?
Do not split, crush, or chew it.Telfast tablets can safely be cut or split in half.
Can I drink orange juice with Telfast?
Do not drink grapefruit juice, apple juice or orange juice while you're taking Telfast. It might make you more likely to get side effects. It's best not to drink alcohol while you're taking Telfast as it can make you feel sleepy.
