title: The effect of trifluoperazine on bronchial responsiveness in asthma.
abstract: 1. The protective effects of oral trifluoperazine (TFP) (7 mg) against standardized methacholine and histamine inhalation tests (MIT and HIT) were examined 2 and 22 h post-treatment in eight stable asthmatics using a randomized double-blind protocol. 2. A preliminary study tested whether a preceding MIT influenced the result of a subsequent HIT. 3. The mean baseline forced expiratory volumes in 1 s (FEV1) were similar prior to placebo and TFP. The mean FEV1 values 2 h after ingestion of placebo or TFP were not different from the baseline values. 4. TFP did not alter bronchial responsiveness to inhaled methacholine or histamine 2 h post-ingestion, but at 22 h the PC20 methacholine was greater than placebo, while PC20 histamine did not change. This change in methacholine responsiveness was not clinically significant. 5. There was a correlation between geometric mean provocative concentration of histamine to cause 20% fall in FEV (PC20H) for HIT performed in isolation ('separate day') and for HIT performed after MIT ('same day'). 6. The effect of inhaled TFP (10 mg/ml, nebulized for 5 min) was examined single-blind and placebo-controlled in a separate group of six stable asthmatics. 7. Inhaled TFP had a bronchoconstrictor effect in all six asthmatics. The mean fall in FEV1 was 36.4% after inhaled TFP and 2.1% after saline. 8. In the asthmatics studied, ingested TFP exhibited a weak anticholinergic effect 22 h post-treatment, but a brisk spontaneously self reverting bronchoconstrictor response was invariably seen when TFP was inhaled.
authors.affiliation: Department of Medicine, Flinders Medical Centre, Bedford Park, South Australia.
authors.forename: J J
authors.initials: JJ
authors.lastname: Bowden
authors.forename: K M
authors.initials: KM
authors.lastname: Latimer
authors.forename: A J
authors.initials: AJ
authors.lastname: Crockett
authors.forename: R E
authors.initials: RE
authors.lastname: Ruffin
mesh_terms: D000293:Adolescent; D000328:Adult; D001249:Asthma / Q000503:physiopathology*; D001980:Bronchi / Q000503:physiopathology*; D004311:Double-Blind Method; D005541:Forced Expiratory Volume; D006632:Histamine / Q000494:pharmacology; D006801:Humans; D008297:Male; D008688:Methacholine Compounds / Q000494:pharmacology; D008875:Middle Aged; D009119:Muscle Contraction / Q000187:drug effects; D016032:Randomized Controlled Trials as Topic; D014268:Trifluoperazine / Q000494:pharmacology*
chemical_list: D008688:Methacholine Compounds; D014268:Trifluoperazine; D006632:Histamine