Terfin (Terfenadine)
Terfin (Terfenadine) Uses, Dosage, Side Effects, Food Interaction and all others data.
Terfin (Terfenadine) competes with histamine for binding at H1-receptor sites in the GI tract, uterus, large blood vessels, and bronchial muscle. This reversible binding of terfenadine to H1-receptors suppresses the formation of edema, flare, and pruritus resulting from histaminic activity. As the drug does not readily cross the blood-brain barrier, CNS depression is minimal.
Terfin (Terfenadine), an H1-receptor antagonist antihistamine, is similar in structure to astemizole and haloperidol, a butyrophenone antipsychotic. The active metabolite of terfenadine is fexofenadine.
| Trade Name | Terfin (Terfenadine) |
| Availability | Discontinued |
| Generic | Terfenadine |
| Terfenadine Other Names | Terfenadin, Terfenadina, Terfénadine, Terfenadine, Terfenadinum |
| Related Drugs | hydroxyzine, loratadine, levocetirizine, Vistaril, Atarax, Xyzal |
| Type | |
| Formula | C32H41NO2 |
| Weight | Average: 471.6734 Monoisotopic: 471.313729561 |
| Protein binding | 70% |
| Groups | Approved, Withdrawn |
| Therapeutic Class | Non-sedating antihistamines |
| Manufacturer | |
| Available Country | Indonesia |
| Last Updated: | September 19, 2023 at 7:00 am |
Uses
Terfin (Terfenadine) is used for the treatment of allergic rhinitis, hay fever, and allergic skin disorders
Terfin (Terfenadine) is an antihistamine. Antihistamines prevent sneezing, runny nose, itching and watering of the eyes, and other allergic symptoms. This is used to treat allergies, hives (urticaria), and other allergic inflammatory conditions. Terfin (Terfenadine) may also be used for purposes other than those listed in this medication guide.
Terfin (Terfenadine) is also used to associated treatment for these conditions: Allergic Rhinitis (AR), Allergies, Allergy Skin, Pollen Allergy
How Terfin (Terfenadine) works
Terfin (Terfenadine) competes with histamine for binding at H1-receptor sites in the GI tract, uterus, large blood vessels, and bronchial muscle. This reversible binding of terfenadine to H1-receptors suppresses the formation of edema, flare, and pruritus resulting from histaminic activity. As the drug does not readily cross the blood-brain barrier, CNS depression is minimal.
Dosage
Terfin (Terfenadine) dosage
Adult (>12 year and >50 kg): 60-120 mg in the morning or 60 mg bid. Max: 120 mg daily.
Renal Impairment: CrCl <40: Half the usual daily dose
Side Effects
Anxiety, palpitations, insomnia, mild GI distubances, erythema multiforme and galactorrhoea.
Toxicity
Mild (e.g., headache, nausea, confusion), but adverse cardiac events including cardiac arrest, ventricular arrhythmias including torsades de pointes and QT prolongation have been reported. LD50=mg/kg (orally in mice)
Precaution
Child and elderly. Avoid in patients with cardiac or significant hepatic disease, electrolyte imbalance, or known or suspected prolongation of the QT interval. Lactation, pregnancy.
Interaction
Increased risk of ventricular arrhythmia with triazole and imidazole antifungals, macrolide antibacterials, streptogramin antibacterials, SSRI, HIV-protease inhibitors and non-nucleoside reverse transcriptase inhibitors, arrhythmogenic drugs, diuretics, astemizole and zileutron.
Food Interaction
- Exercise caution with grapefruit products. Grapefruit is a CYP3A4 inhibitor, and terfenadine is metabolized by CYP3A4. Co-administration may increase terfenadine concentrations and the risk of QT prolongation.
- Exercise caution with St. John's Wort. This herb induces CYP3A4 and terfenadine is a substrate of CYP3A4.
[Major] CONTRAINDICATED: The consumption of grapefruit juice has been associated with significantly increased plasma concentrations of terfenadine.
The mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall induced by certain compounds present in grapefruits.
Terfin (Terfenadine) in high serum levels has been associated with prolongation of the QT interval and development of torsade de pointes, a potentially fatal ventricular arrhythmia.
MANAGEMENT: Due to the risk of cardiotoxicity, patients receiving the drug should be advised to avoid consumption of grapefruit products.
Loratadine, cetirizine, and fexofenadine may be safer alternatives in patients who may have trouble adhering to the dietary restriction.
Terfin (Terfenadine) Drug Interaction
Moderate: halothaneUnknown: acetaminophen / diphenhydramine, aspirin, charcoal, amphetamine / dextroamphetamine, epinephrine, glimepiride, amobarbital, aspirin, amoxicillin / clavulanate, penicillin g benzathine, methohexital, remimazolam, dexamethasone, dextromethorphan, glucose, alvimopan, isoflurane, acetaminophen, phytonadione
Elimination Route
On the basis of a mass balance study using 14C labeled terfenadine the oral absorption of terfenadine was estimated to be at least 70%
Half Life
3.5 hours
Pregnancy & Breastfeeding use
Pregnancy Category C. Either studies in animals have revealed adverse effects on the foetus (teratogenic or embryocidal or other) and there are no controlled studies in women or studies in women and animals are not available. Drugs should be given only if the potential benefit justifies the potential risk to the foetus.
Contraindication
Porphyria.
Innovators Monograph
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FAQ
What is Terfin (Terfenadine) used for?
Terfin (Terfenadine) is used to treat allergies, hives (urticaria), and other allergic inflammatory conditions.
What is the action of Terfin (Terfenadine)?
Terfin (Terfenadine) is an antihistamine. Antihistamines prevent sneezing, runny nose, itching and watering of the eyes, and other allergic symptoms.
What are the common side effects of Terfin (Terfenadine)?
The common side effects of Terfin (Terfenadine) are include: dizziness, syncopal episodes, palpitations, ventricular arrhythmias (including torsades de pointes), cardiac arrest, and cardiac death.
Is Terfin (Terfenadine) safe during pregnancy?
Terfin (Terfenadine) should only be given during pregnancy when there are no alternatives and benefit outweighs the risk.Terfin (Terfenadine) has been assigned to pregnancy category C. Animal studies have failed to reveal evidence of teratogenicity. There are no controlled data in human pregnancy.
Is Terfin (Terfenadine) safe during breastfeeding?
Terfin (Terfenadine) may be preferred in breastfeeding over other antihistamines that do cause sleepiness. Information from Terfin (Terfenadine), which breaks down into Terfin (Terfenadine) in the body, suggests that the amount of Terfin (Terfenadine) in the breast milk is small.
Can I drink alcohol with Terfin (Terfenadine)?
Alcohol may increase drowsiness and dizziness while you are taking Terfin (Terfenadine).
Can I overdose on Terfin (Terfenadine)?
Consider administration of 60 mg of Terfin (Terfenadine) twice daily. Do not over dose Terfin (Terfenadine). It can cause serious cardiovascular events.
What is the Interactions of Terfin (Terfenadine)?
Do not consume alcohol while taking Terfin (Terfenadine). Alcohol can increase the symptoms of dizziness. Do not take caffeine or diet pills while taking Terfin (Terfenadine).
Can Terfin (Terfenadine) cause dizziness?
Terfin (Terfenadine) may cause dizziness or drowsiness. If you experience dizziness or drowsiness, avoid these activities.
Why was Terfin (Terfenadine) removed from the market?
Terfin (Terfenadine) was taken off the market due to the risk of cardiac arrhythmia caused by QT prolongation. The active metabolite is not cardiotoxic, however, and is now sold under the Terfin (Terfenadine) name Allegra.
