Fexofenadine HCl 180 mg, Desloratadine 5 mg and Placebo in Suppression of Wheal and Flare Induced by Histamine

To examine the relative potency, onset of action and duration of action of fexofenadine HCl 180 mg (ALLEGRA) and desloratadine 5 mg (CLARINEX) as compared to placebo on skin wheals and flares induced by histamine.


Eligibility Criteria:
Inclusion Criteria:

* Male and female subjects, 12 to 55 years of age, may participate
* Positive histamine skin prick tests (or duplicate histamine skin prick test) with a summation flare (ΣF) greater than or equal to 20 mm larger than diluent control, and summation wheal (ΣW) greater than or equal to 6 mm larger than diluent control at the screening visit 1
* All female subjects must have a negative urine pregnancy test at the screening visit
* Female subjects who are sexually active will be expected to use one of the following birth control methods throughout the study (see Section 4.4)
* Subjects must be within 15% of normal body weight for height or a BMI less than 29.9 (based on NHLBI guidelines)
* Subjects willing and able to adhere to visit schedules and all study requirements
* All female subjects must have a negative urine pregnancy test at each treatment visit (Visit 2, 4, and 6).
* Continues to meet all inclusion and exclusion criteria

Exclusion Criteria:

* Asthma that requires treatment with medication other than an inhaled, short-acting beta agonist
* Signs and symptoms of currently active allergic disease (seasonal allergic rhinitis, perennial allergic rhinitis, episodic allergic rhinitis)
* Upper respiratory tract infection, sinusitis, asthma or flu-like symptoms within 2 weeks prior to visit 1
* Subjects who have dermatographism or other skin conditions which might interfere with the interpretation of the skin test results
* Subjects who are receiving immunotherapy
* Any excessive amounts of alcohol (no more than two drinks/day on average)
* Any excessive use of caffeine (more than six cups of coffee per day or equivalent)
* Any use of tobacco/nicotine products within 90 days of visit 1
* Any disease state or surgery known to affect the gastrointestinal absorption of drugs
* Known hypersensitivity to the investigational product or to drugs with similar chemical properties
* Subjects who will be visiting a tanning salon during the study
* Subjects who will need to use artificial tanning products during the study
* Night or variable shift workers during the study
* Pregnancy
* Breast-feeding
* History of hypersensitivity to the study medications or to drugs with similar chemical structures
* Treatment with other H1-receptor antagonists in the last year before study entry
* Likelihood of requiring treatment during the study period with drugs not permitted by the clinical study protocol (see Section 6.2)
* Treatment with any investigational product in the last 30 days before study entry
* No person or child of a person directly associated with the administration of the study may participate as a study subject
* Clinically relevant cardiovascular, hepatic, neurologic, endocrine, or other major systemic disease making implementation of the protocol or interpretation of the study results difficult
* Mental condition rendering the subject unable to understand the nature, scope, and possible consequences of the study
* Subject unlikely to comply with protocol, e.g., uncooperative attitude, inability to return for follow-up visits, and unlikelihood of completing the study
* Use of any of the following drugs within the time indicated prior to the first dosing visit: