Bronchodilatory effect

Labdane type diterpenes obviously exhibit a wide spectrum of actions. Primarily forskolin exhibits (a) antihypertensive properties, lowering blood pressure in different animal species through a vasodilatory effect (b) positive inotropic effects in cardiac muscle and (c) bronchodilatory effects [155] and (d) pressure-lowering properties [244]. 

The 5-isomer of albuterol has been shown to oppose the bronchodilatory effects of the eutomer, /J-albuterol and may therefore contribute to paradoxic bronchospasm and the occurrence of severe reagenic-like reactions seen with racemic albuterol. 

Clenbuterol, a P2 adrenoceptor agonist, is sometimes used in pregnant mares with lower airway disease for its bronchodilatory effects. This drug has been found to have minimal effects on fetal heart rate when administered i.v. to mares in the last trimester of pregnancy. The effects on fetal health have not been established. 

Ketamine is not a significant respiratory depressant and the ventilatory response to hypoxia is maintained. Ketamine has a bronchodilatory effect subsequent to sympathetic stimulation. Airway reflexes are well maintained after ketamine administration. However, since ketamine is not used as... 

In 36 patients with chronic obstructive pulmonary disease, the bron-chodilator effect of ipratropium bromide was greater with delivery via Respimat (total dose 160 ttg) than via MDI (total dose of 320 (tg). Between 45 min after the first drug inhalation and 45 min after the final dose, a greater bronchodilatory effect was obtained at half the cumulative dose of ipratropium. The safety profile was similar. 

As noted in Section II, a bronchodilator effect of inhaled NO was demonstrated in guinea pigs (Dupuy et al., 1992) and later in anesthetized rabbits (Hogman et al., 1993b). However, the bronchodilator effect in humans with stable asthma or chronic bronchitis was less dramatic, or absent, in several patients inhaling 80 ppm NO for 10 min (Hogman etal., 1993c). Similar weak bronchodilatory effects of inhaled NO were reported by Kacm-arek et al. (1993). 

Epinephrine activates all adrenoceptors, whereas norepinephrine has minimal agonist activity at [J -adrenoceptors. This difference is important in anaphylaxis because adrenoceptor activation is needed to provide a bronchodilatory effect that will oppose the anaphylaxis-induced airway obstruction. The aj-adrenoceptor agonist effect of epinephrine opposes the anaphylaxis-induced vasodilation and, to some extent, the vascular leak (administration of fluid is also a cornerstone of the treatment of anaphylaxis), while the Pj-adrenoceptor agonist effect helps maintain cardiac output. 

Some clinical benefits of theophylline, including anti-inflammatory, immun-emodulatory, and bronchodilatory effects, already occur at serum concentrations above 5 ag/ml. Thus, these concentrations may be adequate for some patients. In patients receiving theophylline as monotherapy for chronic asthma, however, doses resulting in serum concentrations beyond 10 pg/ml have clearly been shown as most likely to prevent asthma symptoms and decrease the occurrence and severity of exacerbations. 

The chemistry of these phthalazines has been better explored than might be expected, probably because of the biological activities possessed by some. For example, the marked bronchodilatory effects of 2-ethyl-4-(pyridin-3-yl)-l(2//)-phthalazinone (209) and 4-(p-chlorobenzyl)-2-(l-methylhexahydro-17/-azepin-4-yl)-l(2//)-phthalazinone hydrochloride (Azelastin) (210) ° led to the synthesis and investigation of a variety of phthalazinone, fused phthalazine, and nonphthalazine analogs as antiasthmatics. " " °° ... 

Beta blockers, particularly those that are not cardioselective, can cause bronchoconstriction, which opposes the bronchodilatory effects of theophylline. See betaxolol with theophylline and pranlukast , (p.ll60), for mention of a patient who had a deterioration of asthma with this combination. 

The spasmolytic activity of menthol on airway smooth muscle has been demonstrated in vitro (Taddei et al., 1988). To examine the bronchodilatory effects of menthol, a small trial was conducted on six patients with mild to moderate asthma. A poultice containing menthol was applied daily for 4 weeks, and it was found that bronchoconstriction was decreased and airway hyperresponsiveness improved (Chiyotani et al., 1994b). 

A double-blind, randomized clinical trial over 7 days compared oral pure 1,8-cineole (3 x 200 mg/day) to Ambroxol (3 x 30 mg/day) in 29 patients with chronic obstructive pulmonary disease (COPD). Vital capacity, airway resistance, and speci c airway conductance improved signi cantly for both drugs, while the intrathoracic gas volume was reduced by 1,8-cineole but not Ambroxol. All parameters of lung function, peak ow, and symptoms of dyspnea were improved by 1,8-cineole therapy but were not statistically signi cant in comparison to Ambroxol due to the small number of patients. In addition to other properties, it was noted that the oxide seemed to have bronchodilatory effects (Wittman et ah, 1998). 

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