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Farya Zafar / Journal of Pharmacy Research 2012,5(3),1646-1649 Review Article Available online through ISSN: 0974-6943 http://jprsolutions.info A review of Fexofenadine hydrochloride Farya Zafar* Department of Pharmaceutics, Faculty of Pharmacy, University of Karachi, Karachi, Pakistan. Received on:10-12-2011; Revised on: 15-01-2012; Accepted on:12-02-2012 ABSTRACT Fexofenadine is the hydrochloride salt of terfenadine’s active metabolite. In 2006, the FDA approved an oral suspension for the management of chronic idiopathic urticaria and seasonal allergic rhinitis in children. This review article summarizes the clinical pharmacology, therapeutic applications, drug-drug interactions, adverse events and food-drug interactions of fexofenadine that have been reported in pervious years. Key words: Fexofenadine hydrochloride, chronic idiopathic urticaria, clinical pharmacology, therapeutic applications. INTRODUCTION More than 45 H1-antihistamines are accessible worldwide, including the various symptoms such as sneezing, rhinorrhea, nasal pruritus and watery major class of drugs used in the management of allergic disorders [1-5]. eyes [15] associated with allergic rhinitis [16-18]. Authors reported that antihis- Fexofenadine, is a histamine H 1- receptor antagonist having chemical name tamines (second generation) particularly, fexofenadine have anti-inflamma- (+)-4-[1-hydroxy-4-[4-(hydroxydiphenylmethyl)-1-piperidinyl]-butyl]- [19, 15] tory response that may decrease nasal congestion . H1 receptor antago- a,a-dimethylbenzeneaceticacid hydrochloride. The empirical formula and nists usually have slight effect on this indication [20-22]. Antihistamine can be [23- the molecular weight is C32H39NO4.HCl and 538.13, respectively. combined with pseudoephedrine, to give complete symptomatic relief Fexofenadine hydrochloride is a racemate and exists as zwitterions in aque- 25]. ous media at physiological pH [6]. The major therapeutic applications of fexofenadine are as follows: CLINICAL PHARMACOLOGY OF FEXOFENADINE Seasonal allergic rhinitis Mechanism of action Allergic rhinitis is described as inflammation due to an allergic reaction [26]. Fexofenadine is the active metabolite of terfenadine [7, 8]. Fexofenadine hy- Allergic rhinitis is a frequent disorder related with the incidence of morbid- [27] drochloride is an antihistamine having selective peripheral H1- receptor ity . Fexofenadine is particularly renowned for its effective against this antagonist activity. Both enantiomers of fexofenadine hydrochloride showed inflammatory process [28, 26], chronic urticaria [29] and perennial allergic rhini- equivalent antihistaminic response [6]. tis [30]. Fexofenadine may offer equal or superior efficacy in managing aller- gic disorders as compared with other existing second-generation histamine Pharmacokinetics receptor blocker [31-33]. Fexofenadine HCl 60 mg/pseudoephedrine HCl 120 Fexofenadine hydrochloride is absorbed rapidly achieving maximum con- mg is useful in the management of patients having moderate-to-severe sea- centration within 1 to 2 hours [9] after oral administration of a single dose of sonal allergic rhinitis with an excellent safety profile [34]. The effectiveness two 60 mg capsules to male healthy subjects the maximum plasma concen- of fexofenadine hydrochloride (180 mg) and cetirizine (10 mg) in patients tration was achieved after 2.6 hrs post dose. After administration of a single having seasonal allergic rhinitis were determined. It was found that 60 mg capsule to healthy subjects, the mean maximum plasma concentra- fexofenadine hydrochloride (180 mg) once daily given for 2 weeks showed tion was 131ng/mL. After single oral administration of either the 60 and 180 clinically similar progress in symptoms and extensively less drowsiness in mg tablet to male subjects, maximum plasma concentrations were 142 and patients as compared with cetirizine (10 mg) [35, 36]. Also loratadine- 494 ng/mL, respectively. Fexofenadine hydrochloride is 60-70 % bound to montelukast and fexofenadine-pseudoephedrine have equivalent efficacy in [6] [37] plasma proteins, primarily albumin and a 1-acid glycoprotein . Fexofenadine managing the symptoms of nasal obstruction in seasonal allergic rhinitis . hydrochloride undergoes negligible metabolism [10, 11]. Approximately, 5 % Allergic rhinitis affected paediatric residents in a huge percentage. Due to of the total oral dose was metabolized [6]. Fexofenadine is unmetabolized by the availability of number of agents, it has become a test to select the most the liver [9]. Elimination half-life achieved from 13 to 16 hours [12], the mean suitable management for this population. Second-generation antihistamines elimination half life was 14.4 hrs after adminstration of 60 mg twice daily, in are considered relatively secure for use in paediatric population [38, 39]. Segall normal subjects [6]. Approximately, 90% of fexofenadine is found unchanged et al. in 2008 formulated an oral suspension of fexofenadine hydrochloride in the feces and the urine [13]. and evaluated the pharmacokinetic performance, safety and acceptability of oral suspension by administering Fexofenadine HCl (30 mg) as a 6-mg/ THERAPEUTIC APPLICATIONS OF FEXOFENADINE mL suspension (5 mL) to the patients. Plasma samples were collected up to The advantages of H receptor antagonists are well known [14]. The H 1 1 24 hrs. Mean Cmax of fexofenadine was 224 ng/mL and mean AUC was 898 receptor antagonists are the commonly prescribed class of drug for the ng . hour/mL [40]. Similarly, Ngamphaiboon et al. in 2005 suggested the safe management of allergic rhinitis [13]. Antihistamines give useful relief from use of a oral dose of fexofenadine HCl 30 mg (twice-daily) in children aged from 6-11 years having seasonal or perennial allergic rhinitis [41]. Pretreat- ment with fexofenadine could prevent the incidence of severe specific im- *Corresponding author. munotherapy-related systemic reactions facilitated by immunotherapy in Farya Zafar* patients having allergic rhinitis [42]. Department of Pharmaceutics, Faculty of Pharmacy, Chronic idiopathic urticaria University of Karachi, Chronic idiopathic urticaria can have an intense outcome on patient quality Karachi, 75270, Pakistan. of life. Any therapy used to manage chronic idiopathic urticaria without producing side effects is useful [43]. The causes of chronic idiopathic urti- Journal of Pharmacy Research Vol.5 Issue 3.March 2012 1646-1649 Farya Zafar / Journal of Pharmacy Research 2012,5(3),1646-1649 caria include reactions to drugs, food, infections and thyroid disease etc. tance for residents receiving fexofenadine [61]. Drug-drug interactions would For this purpose the use of new low-sedating antihistamines such as be observed when terfenadine and astemizole were prescribed along with desloratadine, fexofenadine and mizolastine should be tried first [44] and antibiotics (macrolide) and/or the antifungal agents (itraconazole or fexofenadine, desloratadine and loratadine should be selected over cetirizine ketoconazole) which may result in severe adverse event including death. [43]. Fexofenadine is well-accepted for the management for chronic idio- Fexofenadine and loratadine are least likely nonsedating antihistamines to pathic urticaria [45-47]. It reduces itching, size, number and duration of wheals facilitate interaction with other drugs [62]. Fexofenadine does not undergo and flares [48]. biotransformation; also coadministration of fexofenadine with ketoconazole, erythromycin and azithromycin may elevate fexofenadine plasma concen- Paclitaxel-induced hypersensitive reactions trations [60]. Itraconazole and verapamil elevated the drug plasma concentra- Patients suffering from Paclitaxel showed intense hypersensitivity reac- tions by inhibiting P-glycoprotein activity [63-66]. The AUC0-8 for (S) - and tions such as blood pressure drop and impaired breathing. Fexofenadine (R) - fexofenadine were considerably elevated by 348 and 238% with prevents different hypersensitive reactions in these patients [49]. verapamil and 401 and 307% with itraconazole, respectively [67]. St. John’s wort and rifampin reduces the drug plasma concentrations of fexofendine Atopic alopecia areata [68, 69]. Inui et al. in 2009 assessed the response of fexofenadine in patients suffer- ing from alopecia areata, for this purpose they examined 121 patients ADVERSE EVENTS retrospectively with alopecia areata having alopecia in > 50% of the scalp. Immense overdoses of H1-antihistamines (second generation) particularly Results indicated that fexofenadine is useful in the management of atopic fexofenadine, cetirizine and loratadine have not been linked with respira- alopecia areata with contact immunotherapy [50]. tory depression, seizures, coma or fatality [70, 48]. In children aged between 2 to 5 years having allergic rhinitis, fexofenadine showed some frequent Histamine-induced wheal and flare adverse events which were fever, upper respiratory tract infection and Meltzer and Gillman in 2007 studied fexofenadine versus desloratadine in vomiting [71]. Kulthanan et al. in 2001 reported the toxicity of fexofenadine decreasing histamine-induced skin flares and wheals in patients. They car- in the patients having chronic idiopathic urticaria. From 108 objects only ried out randomized, two-center, crossover study. Results showed that 20 objects showed the occurrence of only one undesirable event which was fexofenadine decreases skin flares drastically than desloratadine [51]. drowsiness, headache, dizziness, elevation in weight and

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