Allegra-D Contraindications and Precautions
- acute myocardial infarction
- angina
- cardiac arrhythmias
- coronary artery disease
- MAOI therapy
- myocardial infarction
- neonates
- tachycardia
- terfenadine hypersensitivity
- breast-feeding
- cardiac disease
- cardiomyopathy
- children
- closed-angle glaucoma
- diabetes mellitus
- driving or operating machinery
- elderly
- glaucoma
- heart failure
- hypertension
- hyperthyroidism
- pregnancy
- prostatic hypertrophy
- renal disease
- renal failure
- renal impairment
- urinary retention
Allegra-D Contraindications and Precautions
Do not use fexofenadine in patients with a history of terfenadine hypersensitivity due to the similarity in chemical structure.
Fexofenadine should be used cautiously in patients with renal impairment associated with renal disease or renal failure. Peak plasma concentrations were 87% and 111% greater in patients with mild (CrCl 41 - 80 ml/min) to severe (CrCl 11 - 40 ml/min) renal impairment, respectively. Mean elimination half-lives were 59% and 72% longer, respectively, than in normal volunteers. Peak plasma concentrations in dialysis patients (CrCl <= 10 ml/min) were 82% greater and half-life was 31% longer than in normal volunteers. Patients with mild to severe renal impairment should be given half the initial dose due to reduced clearance of fexofenadine and pseudoephedrine.
The incidence of drowsiness was 1.3% in patients receiving fexofenadine monotherapy (vs placebo 0.9%). Patients should be warned about undertaking hazardous tasks (e.g., driving or operating machinery) while taking fexofenadine; pseudoephedrine, although the risk is relatively low.
Due to its pseudoephedrine component, this product should be used with caution in patients with closed-angle glaucoma, diabetes mellitus, hyperthyroidism, or urinary retention due to prostatic hypertrophy, since it can exacerbate these conditions. Central nervous system stimulation with convulsions or cardiovascular collapse and accompanying hypotension may be produced by sympathomimetic amines.
Well-controlled hypertensive adult patients receiving pseudoephedrine at recommended doses (240 mg/day PO) generally do not appear at risk for significant elevations in blood pressure; however, small increases in blood pressure and heart rate may occur. Although considered safe in the general population of controlled hypertensives, increased blood pressure (especially systolic hypertension) has been reported in individual patients receiving pseudoephedrine. Since pseudoephedrine is a vasoconstrictor and may increase heart rate via sympathomimetic effects, it should be avoided in patients with uncontrolled or severe hypertension, acute cardiac arrhythmias (tachycardias), or severe coronary artery disease (including acute myocardial infarction, angina, or history of myocardial infarction). Considerable caution should be used in patients with controlled or mild hypertension, heart failure, cardiomyopathy, or other cardiac disease.
Pseudoephedrine-containing products should not be combined with MAOI therapy (see Drug Interactions).
Clinical studies did not include sufficient numbers of patients aged 65 and older to determine whether they respond differently to fexofenadine; pseudoephedrine than younger adult patients. However, elderly patients are more likely to have decreased renal clearance of fexofenadine and pseudoephedrine (see Pharmacokinetics) as well as adverse reactions to sympathomimetic amines. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range.
The combination product, fexofenadine; pseudoephedrine is classified as pregnancy category C. Results of animal studies using fexofenadine as a single agent have revealed an absence of mutagenicity or infertility. Teratogenicity was not observed in rats given approximately 15 times the maximum daily oral dose of fexofenadine in humans based on an AUC comparison. Decreased pup weight gain and survival occurred in rats given 3 times the maximum daily oral dose of fexofenadine in humans. There have been no adequate and well-controlled studies on the use of fexofenadine or the combination product in human pregnancy. Fexofenadine; pseudoephedrine should be used during pregnancy only when the benefits of therapy outweigh the risks.
It is unknown if fexofenadine is excreted into human breast milk. Pseudoephedrine is distributed into human breast milk; milk pseudoephedrine concentrations are consistently higher than plasma concentrations. The total amount of pseudoephedrine (measured by AUC) in milk is 2 - 3 times that of plasma. The fraction of a pseudoephedrine dose excreted in milk is estimated to be 0.4 - 0.7%. Fexofenadine; pseudoephedrine should be used during breast-feeding only when the benefits of therapy outweigh the risks.
The safety and effectiveness of fexofenadine; pseudoephedrine in children under 12 years of age have not been established. The adverse effects of sympathomimetics such as pseudoephedrine can be severe, especially in infants and toddlers; CNS stimulation, hypertension and tachycardia may occur. Antihistamines generally should not be used in neonates due to the possibility of paradoxical CNS stimulation or seizures.
[ Last revised: 1/4/2006 10:06:00 PM ]
References
. Coates ML, et al. Does pseudoephedrine increase blood pressure in patients with controlled hypertension? J Fam Pract 1995;40:22 - 6.
. Chua SS, Benrimoj SI. Non-prescription sympathomimetic agents and hypertension. Med Toxicol Adverse Drug Exp 1988;3:387 - 417.
. Gunn VL, Taha SH, Liebelt EL et al. Toxicity of over-the counter cough and cold medications. Pediatrics 2001;108:1 - 5.
. Beck RA, Mercado DL, Seguin SM, et al. Cardiovascular effects of pseudoephedrine in medically controlled hypertensive patients. Arch Intern Med 1992;152:1242 - 5.
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