Allergy Relief (FEXOFENADINE) (fexofenadine HCl)

Adjustment of fexofenadine hydrochloride dosage may be necessary in patients with renal impairment. Peak plasma fexofenadine concentrations increased by 87 or 111%, and elimination half-life increased by 59 or 72% in patients with mild (e.g., creatinine clearance of 41-80 mL/minute) or severe (creatinine clearance of 11-40 mL/minute) renal impairment, respectively, when compared with those observed in healthy individuals. In addition, peak plasma fexofenadine concentration increased by 82% and elimination half-life increased by 31% in those on hemodialysis (creatinine clearance of 10 mL/minute or less) compared with healthy individuals.

The manufacturer states that adults and children 12 years of age and older with impaired renal function or those on hemodialysis should receive an initial fexofenadine hydrochloride dosage of 60 mg daily (either given alone or in fixed combination with 120 mg of pseudoephedrine hydrochloride (Allegra-D(R) 12 Hour)). The fixed-combination preparation containing 180 mg of fexofenadine hydrochloride and 240 mg of pseudoephedrine hydrochloride (Allegra-D(R) 24 Hour) generally should be avoided in patients with renal impairment because of a possible risk of accumulation of pseudoephedrine.

Children 6 to younger than 12 years of age with impaired renal function should receive an initial fexofenadine hydrochloride dosage of 30 mg daily.

Since the pharmacokinetics of fexofenadine do not appear to be altered in patients with hepatic impairment, the manufacturer states that dosage adjustment is not necessary in such patients. The manufacturer of Allegra-D(R) 12 Hour and Allegra-D(R) 24 Hour does not make specific recommendations for dosage adjustment in patients with hepatic impairment, although it is not known if pharmacokinetics of pseudoephedrine are altered in patients with hepatic impairment.

Fexofenadine hydrochloride is administered orally. The manufacturer states that when fexofenadine hydrochloride is given alone (i.e., not in fixed combination with pseudoephedrine hydrochloride) the drug may be given without regard to meals. Since absorption and peak plasma concentrations of fexofenadine are decreased by concomitant administration of an aluminum and magnesium hydroxides antacid (Maalox(R)) (see Pharmacokinetics: Absorption and see Drug Interactions: Antacids), the manufacturer recommends that the drug not be taken closely in time with an antacid containing aluminum and magnesium. Since food appears to substantially affect the rate and extent of absorption of fexofenadine hydrochloride when administered as the extended-release tablets of the drug in fixed combination with pseudoephedrine hydrochloride, the manufacturer states that such extended-release tablets should be administered on an empty stomach with water. (See Pharmacokinetics: Absorption and see Drug Interactions: Fruit Juices.) Extended-release tablets containing fexofenadine hydrochloride in fixed combination with pseudoephedrine hydrochloride should be swallowed intact, and patients should be instructed not to break, crush, or chew such tablets.

There is no enhanced messaging for this drug.

There are no contraindication interactions for this drug.

Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

Agents That Affect Iodide/Radioactive Iodide

SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

MECHANISM OF ACTION: Many compounds can affect iodide protein binding and alter iodide pharmacokinetics and pharmacodynamics.(1)

CLINICAL EFFECTS: Compounds that affect iodide pharmacokinetics and pharmacodynamics may impact the effectiveness of radioactive iodide.(1)

PREDISPOSING FACTORS: Compounds that affect iodide pharmacokinetics and pharmacodynamics are expected to have the most impact during therapy using radioactive iodide. Diagnostic procedures would be expected to be impacted less.

PATIENT MANAGEMENT: Discuss the use of agents that affect iodide pharmacokinetics and pharmacodynamics with the patient's oncologist.(1) Because indocyanine green contains sodium iodide, the iodine-binding capacity of thyroid tissue may be reduced for at least one week following administration. Do not perform radioactive iodine uptake studies for at least one week following administration of indocyanine green.(2) The manufacturer of iopamidol states administration may interfere with thyroid uptake of radioactive iodine and decrease therapeutic and diagnostic efficacy. Avoid thyroid therapy or testing for up to 6 weeks post administration of iopamidol.(3)

DISCUSSION: Many agents interact with radioactive iodine. The average duration of effect is: anticoagulants - 1 week antihistamines - 1 week anti-thyroid drugs, e.g: carbimazole, methimazole, propylthiouracil - 3-5 days corticosteroids - 1 week iodide-containing medications, e.g: amiodarone - 1-6 months expectorants - 2 weeks Lugol solution - 3 weeks saturated solution of potassium iodine - 3 weeks vitamins - 10-14 days iodide-containing X-ray contrast agents - up to 1 year lithium - 4 weeks phenylbutazone - 1-2 weeks sulfonamides - 1 week thyroid hormones (natural or synthetic), e.g.: thyroxine - 4 weeks tri-iodothyronine - 2 weeks tolbutamide - 1 week topical iodide - 1-9 months (1)

Agents That Affect Iodide/Sodium Iodide I 131

SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

MECHANISM OF ACTION: Many compounds can affect iodide protein binding and alter iodide pharmacokinetics and pharmacodynamics.(1,2)

CLINICAL EFFECTS: Compounds that affect iodide pharmacokinetics and pharmacodynamics may impact the effectiveness of radioactive iodide.(1,2)

PREDISPOSING FACTORS: Compounds that affect iodide pharmacokinetics and pharmacodynamics are expected to have the most impact during therapy using radioactive iodide. Diagnostic procedures would be expected to be impacted less.

PATIENT MANAGEMENT: Discuss the use of agents that affect iodide pharmacokinetics and pharmacodynamics with the patient's oncologist.(1,2) Because indocyanine green contains sodium iodide, the iodine-binding capacity of thyroid tissue may be reduced for at least one week following administration. Do not perform radioactive iodine uptake studies for at least one week following administration of indocyanine green.(3) The manufacturer of iopamidol states administration may interfere with thyroid uptake of radioactive iodine and decrease therapeutic and diagnostic efficacy. Avoid thyroid therapy or testing for up to 6 weeks post administration of iopamidol.(4)

DISCUSSION: Many agents interact with radioactive iodine. The average duration of effect is: anticoagulants - 1 week antihistamines - 1 week anti-thyroid drugs, e.g: carbimazole, methimazole, propylthiouracil - 3-5 days corticosteroids - 1 week iodide-containing medications, e.g: amiodarone - 1-6 months expectorants - 2 weeks Lugol solution - 3 weeks saturated solution of potassium iodine - 3 weeks vitamins - 10-14 days iodide-containing X-ray contrast agents - up to 1 year lithium - 4 weeks phenylbutazone - 1-2 weeks sulfonamides - 1 week thyroid hormones (natural or synthetic), e.g.: thyroxine - 4 weeks tri-iodothyronine - 2 weeks tolbutamide - 1 week topical iodide - 1-9 months (1,2)

There are no moderate interactions for this drug.

There is no enhanced messaging for this drug.

There are no contraindication contraindications for this drug.

There are no severe contraindications for this drug.

• Kidney disease with reduction in glomerular filtration rate (GFr)

There is no enhanced messaging for this drug.

Rare or Very Rare

• Acute bacterial otitis media
• Anaphylaxis
• Hypersensitivity drug reaction
• Upper respiratory infection
• Urticaria

Less Frequent

• Back pain
• Dizziness
• Drowsy
• Dysmenorrhea
• Dyspepsia
• Fatigue
• Headache disorder
• Myalgia
• Nausea
• Pharyngitis
• Sinusitis
• Skin rash
• Viral infection
• Vomiting
• Xerostomia

Rare or Very Rare

• Abdominal pain with cramps
• Agitation
• Blurred vision
• Cough
• Earache
• Fever
• Insomnia
• Nervousness
• Nightmares
• Pain
• Pruritus of skin

No enhanced messaging available.

No enhanced messaging available.

Reproduction studies in mice receiving fexofenadine doses up to 3730 mg/kg (approximately 10-15 times the maximum recommended daily oral human dosage of fexofenadine hydrochloride in adults) have not revealed evidence of adverse or teratogenic effects during gestation. Reproduction studies in rats and rabbits using oral terfenadine dosages up to 300 mg/kg resulting in fexofenadine exposure levels calculated to be about 3-4 and 25-31 times, respectively, those resulting from the maximum recommended daily oral human dosage of fexofenadine hydrochloride in adults have not revealed evidence of teratogenicity. However, in rats, oral terfenadine dosages of 150 mg/kg, resulting in fexofenadine exposure levels calculated to be about 3-4 times those resulting from the maximum recommended daily oral human dosage of fexofenadine hydrochloride in adults (based on comparison of the AUC), were associated with decreased weight gain and neonatal survival in the pups.

Reproduction studies in rats and rabbits using terfenadine and pseudoephedrine hydrochloride in a fixed-combination ratio of 1:2 at dosages of 150/300 (corresponding to fexofenadine AUCs of about 3-4 times the maximum recommended adult therapeutic value and to pseudoephedrine hydrochloride dosages about 10 times the maximum recommended human adult daily oral dosage, on a mg/m2 basis) and 100/200 mg/kg daily (corresponding to fexofenadine AUCs of about 8-10 times the maximum recommended adult therapeutic value and to pseudoephedrine hydrochloride dosages about 15 times the maximum recommended human adult daily oral dosage, on a mg/m2 basis), respectively, have revealed evidence of reduced fetal weight; delayed ossification with wavy ribs also was observed in rats receiving the drug at these dosages.

There are no adequate and controlled studies to date using fexofenadine in pregnant women, and fexofenadine hydrochloride alone or in fixed combination with pseudoephedrine hydrochloride should be used during pregnancy only when the potential benefits justify the possible risks to the fetus.

It is not known if fexofenadine hydrochloride is distributed into breast milk; however, pseudoephedrine hydrochloride distributes into breast milk. Since there are no adequate and controlled studies to date on the use of fexofenadine during lactation in humans and because many drugs are excreted in human milk, the manufacturer states that fexofenadine alone or in fixed combination with pseudoephedrine hydrochloride should be used with caution in nursing women, and a decision should be made whether to discontinue nursing or the drug, taking into account the importance of the drug to the woman.

No enhanced messaging available.