Multicenter, double-blind, placebo-controlled trial of terfenadine in seasonal allergic rhinitis and conjunctivitis.

A multiclinic, double-blind, parallel and controlled study was conducted in the 1982 spring pollen season to evaluate and compare the effects of terfenadine, 60 mg bid with those of chlorpheniramine 4 mg tid and placebo for a treatment period of seven days in patients with seasonal allergic rhinitis and conjunctivitis. Of a total of 397 patients enrolled in the seven study centers, 345 patients were accepted for evaluation of efficacy and 393 patients for safety. The results show that based on the physicians' assessment of the overall efficacy, terfenadine was significantly superior to placebo and comparable to chlorpheniramine in the relief of allergic symptoms, with moderate to complete relief being observed in 60% (68/113) of the terfenadine-treated patients, in 60% (71/119) of the chlorpheniramine-treated patients, and in 30% (34/119) of the placebo-treated patients. The daily evaluation of severity of symptoms by the patients show that the effect of terfenadine and chlorpheniramine was evident on the first day after entry, reached a peak on the second day after entry, and persisted thereafter. Side effects were minor and infrequent in all treatment groups. There was no statistically significant difference in the incidence of sedation between the terfenadine (7.6%) and placebo (2.4%) groups whereas the incidence of sedation with chlorpheniramine (19%) was significantly higher. In conclusion, terfenadine is as effective as chlorpheniramine in the treatment of symptoms of seasonal allergic rhinitis and conjunctivitis with an incidence of sedation not significantly different from that with placebo and significantly less than with chlorpheniramine.

Treatment of allergic rhinitis with a new selective H1 antihistamine: terfenadine.

The effectiveness of 60 mg b.i.d. of a novel antihistamine, terfenadine, was compared with an active control, 4 mg t.i.d. of chlorpheniramine, and placebo in 560 patients with seasonal allergic rhinitis. In contrast to the gradual decrease in seasonal symptoms observed over a 7 day period of study in placebo-treated patients, both antihistamines produced a prompt significant decrease in sneezing and rhinorrhea, and a gradual decrease in nasopharyngeal pruritus. Terfenadine-related sedation did not differ from that produced by the placebo and was less than the sedation produced by the active control.

The lectin reactivity and lectin-like activity of allergenic pollen extracts.

The binding of soluble components of pollen grains to plant-stigma receptors can be inhibited by concanavalin A. This lectin-like activity of pollen components is important in the genetic control of plant reproduction. Aqueous extracts of allergenic pollens also react with concanavalin A. Agarose gel-diffusion precipitates were used to survey and characterize the ability of allergenic pollen extracts to react with concanavalin A and other lectins. Concanavalin A alone precipitated with extracts of plantain, American beech, white ash, and corn pollens. Surprisingly, extracts of the pollen from certain plants also precipitated when the extracts were diffused against pollen extracts from other plants. Pollen extracts of alfalfa, white ash, American beech, burweed marsh elder, redtop grass, corn, plantain, orchard grass, and aspen reacted with one or more other pollen extracts. Extract precipitin activity was reliably obtained after extracting pollens for 20 min with pH 7.5, 0.05M Tris buffer in 0.2M of saline. Optimal agarose gel conditions for detecting the precipitin reactions were pH 8.5 to 9.0, 75 mM borate buffer made to an ionic strength of 1.5M with NaCl for concanavalin A pollen reactions and 0.015M with NaCl for pollen-pollen reactions. The presence of the borate ion was necessary for optimal detection of the agarose gel precipitates. Studies of the inhibition of the lectin-pollen and pollen-pollen reactions with specific mono and disaccharides revealed many similarities and differences between the two types of reactions. The high concentrations of glycerol used to stabilize pollen extracts also inhibit these reactions.