Subject(s)
Humans , Asthma/drug therapy , Histamine H1 Antagonists , Histamine/adverse effects , Receptors, Histamine H1/physiology , Asthma/physiopathology , Histamine H1 Antagonists/classification , Histamine H1 Antagonists/pharmacology , Receptors, Histamine H1/drug effects , Bronchial Provocation Tests/statistics & numerical data , Bronchial Provocation Tests/standards , Treatment OutcomeABSTRACT
Contribution of histamine H1- and H2-receptors to the effect of compound 48/80, a potent histamine releaser, upon asphyxiation and body temperature in mice was investigated in the present experiments. Compound 48/80 showed an apparent protective potency against hypoxia and significantly prolonged the latencies for convulsions and death in a dose-dependent manner. Compound 48/80 also decreased the body temperature, which was in relation with the antihypoxic effect. Both the H1-receptor antagonist, dimethindene, and the H2-receptor antagonist, ranitidine, attenuated the hypothermic effect of compound 48/80, indicating the involvement of central histamine through both the H1- and H2-receptors. Ranitidine had no effect on the protective effect of compound 48/80 against hypoxia-induced lethality, whereas dimethindene completely antagonized it. These results suggest that the protective effect of compound 48/80 against hypoxia is mediated through histamine H1-receptors and is not related to its ability to induce hypothermia.
Subject(s)
Male , Mice , Animals , Hypoxia/drug therapy , Body Temperature/drug effects , Seizures/prevention & control , Mice, Inbred BALB C , Receptors, Histamine H1/physiology , Receptors, Histamine H2/physiology , p-Methoxy-N-methylphenethylamine/pharmacologyABSTRACT
Para demostrar la bioequivalencia de dos formulaciones de Terfenadina, se diseño un estudio de equivalencia clínica, en el que se evaluó la eficacia del antihistamínico en la prevención de la respuesta por reto con histamina intradérmica en 12 voluntarios sanos, en un modelo doble ciego, cruzado, por bloques de tratamiento asignados aleatoriamente y durante siete días. Se determinó la respuesta dérmica de concentraciones de histamina de 0, 1, 5 y 10 mcg, mediante la medición de las ronchas provocadas tras su inyección en la región deltoidea, esto se hizo de control, una hora después de la primera dosis y 11 hioras después de la segunda y la última dosis de cada tratamiento. Los resultados obtenidos demostraron semejanza en cuanto a latencia, magnitud y duración del efecto protector al reto histamínico con ambas formulaciones, esto comprueba su equivalencia clínica y sugiere similar biodisponibilidad