Article: Fexofenadine

Fexofenadine
Systematic (IUPAC) name
2-[4-[1-hydroxy-4-[4-(hydroxy-diphenyl- methyl)-1-piperidyl]butyl]phenyl]-2- methyl-propanoic acid
Identifiers
CAS number	83799-24-0
ATC code	R06A626
PubChem	3348
DrugBank	APRD00349
Chemical data
Formula	C32H39NO4
Mol. weight	501.656
Pharmacokinetic data
Bioavailability	Not yet established
Protein binding	60-70%
Metabolism	Hepatic (5% of dose)
Half life	14.4 hours
Excretion	Biliary , fecal and renal
Therapeutic considerations
Pregnancy cat.	C (US) B2 (Australia)
Legal status	Prescription Only (US, UK) OTC (Canada, Australia)
Routes	Oral

Fexofenadine hydrochloride (brand names include Allegra® and Telfast®) is an antihistamine drug used in the treatment of hayfever and similar allergy symptoms. It was developed as a successor of and alternative to terfenadine, an antihistamine with potentially fatal contraindications. Fexofenadine, like other second-generation antihistamines, does not readily enter the brain from the blood, and so causes less drowsiness than first-generation histamine-receptor antagonists.

Common Side Effects

• Nausea
• Vomiting
• Weakness
• Drowsiness, sleepiness
• Depression

Overdose

Reports of Fexofenadine overdose are infrequent, and because of this, the effects are not well established. No deaths occurred in testing on mice, at 5000mg/kg, which is 110 times the maximum recommended dose for an adult human. Further research shows no deaths in rats at the same concentration, which equates four hundred times the recommended dose in an adult human. Research on humans ranges from a single 800mg dose, to a twice-daily 690mg dose for a month, with no clinically significant adverse effects, when compared to a placebo.

History

Fexofenadine was developed by Hoechst Marion Roussel (now part of Aventis) and approved by the Food and Drug Administration (FDA) in 1996. Since that time, it has achieved blockbuster drug status with global sales of $1.87B USD in 2004 (with $1.49B USD coming from the United States).