Information for Patients
Patients taking Fexofenadine Hydrochloride Tablets should receive
the following information:
Fexofenadine Hydrochloride Tablets are prescribed for the relief of symptoms
of seasonal allergic rhinitis or for the relief of symptoms of chronic
idiopathic urticaria (hives). Patients should be instructed to take Fexofenadine
Hydrochloride Tablets only as prescribed. Do not exceed the recommended dose. If
any untoward effects occur while taking Fexofenadine Hydrochloride Tablets,
discontinue use and consult the doctor.
The product should not be used by patients who are hypersensitive to it or to
any of its ingredients.
Patients should be told that this product should be used in pregnancy or
lactation only if the potential benefit justifies the potential risk to the
fetus or nursing infant.
Patients should be advised to take the tablet with water. Patients should
also be advised to store the medication in a tightly closed container in a cool,
dry place, away from children.
Drug Interaction with Erythromycin and
Ketoconazole
Fexofenadine has been shown to exhibit minimal (ca. 5%)
metabolism. However, co-administration of fexofenadine hydrochloride with either
ketoconazole or erythromycin led to increased plasma concentrations of
fexofenadine. Fexofenadine had no effect on the pharmacokinetics of either
erythromycin or ketoconazole. In 2 separate studies, fexofenadine hydrochloride
120 mg twice daily (240 mg total daily dose) was co-administered with either
erythromycin 500 mg every 8 hours or ketoconazole 400 mg once daily under
steady-state conditions to healthy volunteers (n=24, each study). No differences
in adverse events or QTc interval were observed when
subjects were administered fexofenadine hydrochloride alone or in combination
with either erythromycin or ketoconazole. The findings of these studies are
summarized in the following table:
Effects on steady-state fexofenadine pharmacokinetics after 7 days of
co-administration with fexofenadine hydrochloride 120 mg every 12 hours (two
times the recommended twice daily dose) in healthy volunteers (n=24)| Concomitant Drug | CmaxSS (Peak plasma concentration) | AUCss(0–12h) (Extent of systemic exposure) |
|---|
| Erythromycin | +82% | +109% |
| (500 mg every 8 hrs) |
|
|
| Ketoconazole | +135% | +164% |
| (400 mg once daily) |
|
|
The changes in plasma levels were within the range of plasma levels achieved
in adequate and well-controlled clinical trials.
The mechanism of these interactions has been evaluated in in vitro, in situ, and in vivo
animal models. These studies indicate that ketoconazole or erythromycin
co-administration enhances fexofenadine gastrointestinal absorption. This
observed increase in the bioavailability of fexofenadine may be due to
transport-related effects, such as p-glycoprotein. In
vivo animal studies also suggest that in addition to enhancing
absorption, ketoconazole decreases fexofenadine gastrointestinal secretion,
while erythromycin may also decrease biliary excretion.
Drug Interactions with Antacids
Administration of 120 mg of fexofenadine hydrochloride (2 × 60 mg
capsule) within 15 minutes of an aluminum and magnesium containing antacid
(Maalox®) decreased fexofenadine AUC by 41% and Cmax by
43%. Fexofenadine hydrochloride should not be taken closely in time with
aluminum and magnesium containing antacids.
Interactions with Fruit Juices
Fruit juices such as grapefruit, orange and apple may reduce the
bioavailability and exposure of fexofenadine. This is based on the results from
3 clinical studies using histamine induced skin wheals and flares coupled with
population pharmacokinetic analysis. The size of wheal and flare were
significantly larger when fexofenadine hydrochloride was administered with
either grapefruit or orange juices compared to water. Based on the literature
reports, the same effects may be extrapolated to other fruit juices such as
apple juice. The clinical significance of these observations is unknown. In
addition, based on the population pharmacokinetics analysis of the combined data
from grapefruit and orange juices studies with the data from a bioequivalence
study, the bioavailability of fexofenadine was reduced by 36%. Therefore, to
maximize the effects of fexofenadine, it is recommended that Fexofenadine
hydrochloride should be taken with water (see Dosage and
Administration).
CARCINOGENESIS, MUTAGENESIS, IMPAIRMENT OF
FERTILITY
The carcinogenic potential and reproductive toxicity of
fexofenadine hydrochloride were assessed using terfenadine studies with adequate
fexofenadine hydrochloride exposure (based on plasma
area-under-the-concentration vs. time [AUC] values). No evidence of
carcinogenicity was observed in an 18-month study in mice and in a 24-month
study in rats at oral doses up to 150 mg/kg of terfenadine (which led to
fexofenadine exposures that were approximately 3 and 5 times the exposure from
the maximum recommended human daily oral dose of fexofenadine hydrochloride in
adults [180 mg] and children [60 mg] respectively .
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 hydrochloride revealed no evidence of mutagenicity.
In rat dietary fertility studies, dose-related reductions in implants and
increases in postimplantation losses were observed at an oral dose of 150 mg/kg
of terfenadine (which led to fexofenadine hydrochloride exposures that were
approximately 3 times the exposure of the maximum recommended human daily oral
dose of 180 mg fexofenadine hydrochloride). In mice, fexofenadine hydrochloride
produced no effect on male or female fertility at average dietary doses up to
4438 mg/kg (approximately 10 times the maximum recommended human daily oral dose
of fexofenadine hydrochloride 180 mg based on comparison of AUCs).
PREGNANCYTeratogenic Effects
Category C.
There was no evidence of teratogenicity in rats or rabbits at oral doses of
terfenadine up to 300 mg/kg (which led to fexofenadine exposures that were
approximately 3 and 30 times, respectively, the exposure from the maximum
recommended human daily oral dose of fexofenadine hydrochloride of 180 mg based
on comparison of AUCs).
In mice, no adverse effects and no teratogenic effects during gestation were
observed with fexofenadine at dietary doses up to 3730 mg/kg (approximately 15
times the maximum recommended human daily oral dose of fexofenadine
hydrochloride 180 mg based on comparison of AUCs).
There are no adequate and well controlled studies in pregnant women.
Fexofenadine 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 an oral dose of 150 mg/kg of terfenadine
(approximately 3 times the maximum recommended human daily oral dose of
fexofenadine hydrochloride of 180 mg in adults based on comparison of
fexofenadine hydrochloride AUCs).
NURSING MOTHERS
It is not known if fexofenadine is excreted in human milk. There
are no adequate and well-controlled studies in women during lactation. Because
many drugs are excreted in human milk, caution should be exercised when
fexofenadine hydrochloride is administered to a nursing woman.
PEDIATRIC USE
The recommended dose in patients 6 to 11 years of age is based on
cross-study comparison of the pharmacokinetics of fexofenadine hydrochloride in
adults and pediatric subjects and on the safety profile of fexofenadine
hydrochloride in both adult and pediatric subjects at doses equal to or higher
than the recommended doses.
The safety of fexofenadine hydrochloride tablets at a dose of 30 mg twice
daily has been demonstrated in 438 pediatric subjects 6 to 11 years of age in
two placebo-controlled 2-week seasonal allergic rhinitis trials. The safety of
fexofenadine hydrochloride for the treatment of chronic idiopathic urticaria in
subjects 6 to 11 years of age is based on cross-study comparison of the
pharmacokinetics of fexofenadine hydrochloride in adult and pediatric subjects
and on the safety profile of fexofenadine in both adult and pediatric subjects
at doses equal to or higher than the recommended dose.
The effectiveness of fexofenadine hydrochloride for the treatment of seasonal
allergic rhinitis in subjects 6 to 11 years of age was demonstrated in 1 trial
(n=411) in which fexofenadine hydrochloride tablets 30 mg twice daily
significantly reduced total symptom scores compared to placebo, along with
extrapolation of demonstrated efficacy in subjects aged 12 years and above, and
the pharmacokinetic comparisons in adults and children. The effectiveness of
fexofenadine hydrochloride for the treatment of chronic idiopathic urticaria in
patients 6 to 11 years of age is based on an extrapolation of the demonstrated
efficacy of fexofenadine hydrochloride 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.
Three clinical safety studies comparing 15 mg twice daily (n=85) and 30 mg
twice daily (n=330) of an experimental formulation of fexofenadine to placebo
(n=430) have been conducted in pediatric subjects aged 6 months to 5 years. In
general, fexofenadine hydrochloride was well tolerated in these studies. No
unexpected adverse events were seen given the known safety profile of
fexofenadine and likely adverse reactions for this patient population. (See ADVERSE REACTIONS and CLINICAL
PHARMACOLOGY.)
The safety and effectiveness of fexofenadine hydrochloride in pediatric
patients under 6 years of age have not been established.
GERIATRIC USE
Clinical studies of fexofenadine hydrochloride tablets and
capsules did not include sufficient numbers of subjects aged 65 years and over
to determine whether this population responds differently from younger subjects.
Other reported clinical experience has not identified differences in responses
between the geriatric and younger subjects. 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 it may be useful to monitor renal function. (See CLINICAL PHARMACOLOGY).