Telfast Special Precautions

Tablet: Carcinogenicity, Mutagenicity & Impairment of Fertility: The carcinogenic potential and reproductive toxicity of fexofenadine HCl were assessed using terfenadine studies with adequate fexofenadine exposure [based on plasma area-under-the-curve (AUC) values]. No evidence of carcinogenicity was observed when mice and rats were given daily oral doses of 50 and 150 mg/kg of terfenadine for 18 and 24 months, respectively; these doses resulted in plasma AUC values of fexofenadine that were up to 4 times the human therapeutic value (based on a 60-mg twice-daily fexofenadine HCl dose).
In in vitro (Bacterial Reverse Mutation, CHO/HGPRT Forward Mutation and Rat Lymphocyte Chromosomal Aberration assays) and in vivo (Mouse Bone Marrow Micronucleus assay) tests, fexofenadine HCl revealed no evidence of mutagenicity.
In rat fertility studies, dose-related reductions in implants and increases in post-implantation losses were observed at oral doses ≥150 mg/kg of terfenadine; these doses produced plasma AUC values of fexofenadine that were ≥3 times the human therapeutic value (based on a 60-mg twice-daily fexofenadine HCl dose).
Reproduction and fertility studies with terfenadine in rats produced no effect on male or female fertility at oral doses up to 300 mg/kg/day. However, reduced implants and post implantation losses were reported at 300 mg/kg. A reduction in implants was also observed at an oral dose of 150 mg/kg/day. Oral doses of 150 and 300 mg/kg of terfenadine produced AUC values of fexofenadine that were approximately 3 and 4 times, respectively, the human AUC at the maximum recommended daily oral dose in adults.
Oral suspension: Do not exceed the recommended dose.
In case of an adverse event during the treatment with TELFAST (ORAL SUSPENSION), discontinue the medication and seek medical assistance.
Avoid taking TELFAST (ORAL SUSPENSION), with food rich in fat.
It is recommended that the medicine be taken with water. Avoid taking it with fruit juice.
Use in Pregnancy: Teratogenic Effects: Pregnancy Category C: There was no evidence of teratogenicity in rats or rabbits at oral terfenadine doses up to 300 mg/kg; these doses produced fexofenadine plasma AUC values that were up to 4, 30 and 37 times the human therapeutic value (based on a 60-mg twice-daily fexofenadine HCl dose), respectively. 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.
Nonteratogenic Effects: Dose-related decreases in pup weight gain and survival were observed in rats exposed to oral doses ≥150 mg/kg of terfenadine; at these doses, the plasma AUC values of fexofenadine were ≥3 times the human therapeutic values (based on a 60-mg twice-daily fexofenadine HCl dose).
Use in Lactation: It is not known if fexofenadine is excreted in human milk. Because many drugs are excreted in human milk, caution should be used when fexofenadine HCl is administered to a nursing woman.
Use in Children: Tablet: The recommended dose in patients 6-11 years is based on cross-study comparison of the pharmacokinetics of Telfast in adults and pediatric patients and on the safety profile of fexofenadine HCl in both adult and pediatric patients at dose equal to or higher than the recommended doses.
The safety of Telfast tablets at a dose of 30 mg twice daily has been demonstrated in 438 pediatric patients (6-11 years) in 2 placebo-controlled 2-week seasonal allergic rhinitis trials. The safety of Telfast for the treatment of chronic idiopathic urticaria in patients (6-11 years) is based on cross-study comparison of the pharmacokinetics of Telfast in adult and pediatric patients and on the safety profile of fexofenadine in both adult and pediatric patients at doses equal to or higher than the recommended dose.
The effectiveness of Telfast for the treatment of seasonal allergic rhinitis in patients (6-11 years) was demonstrated in 1 trial (n=411) in which Telfast 30-mg tablets twice daily significantly reduced total symptom scores compared to placebo, along with extrapolation of demonstrated efficacy in patients ≥12 years, and the pharmacokinetic comparisons in adults and children. The effectiveness of Telfast for the treatment of chronic idiopathic urticaria in patients (6-11 years) is based on an extrapolation of the demonstrated efficacy of Telfast in adults with this condition and the likelihood that the disease course, pathophysiology and the drug's effect are substantially similar in children to that of adult patients.
The safety and effectiveness of Telfast in pediatric patients <6 years have not been established.
Use in the Elderly: Tablet: Clinical studies of Telfast did not include sufficient numbers of subjects ≥65 years to determine whether this population responds differently from younger patients. Other reported clinical experience has not identified differences in responses between the geriatric and younger patients. This drug is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and may be useful to monitor renal function. (See Pharmacology under Actions).
In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.