Bronchodilators adrenergic agonists

Beta adrenergic agonists also exert bronchodilating effects. These drugs are thus often used in conjunction with theophiline in asthma therapy. A drug that combines both moieties, reproterol (40), has interestingly proved... 

The dose of bronchodilator can be gradually reduced based on both symptomatic and objective improvement until the patient returns to pre-exacerbation use of short-acting P2-adrenergic agonist pharmacotherapy... 

As greater control of the disease state is achieved with aerosol therapy, manufacturers are considering combining some of their most successful products to achieve bronchodilation and anti-inflammatory effect in a single dose. These combinations may increase interest in the use of anticholinergics in addition to fl2-adrenergic agonists. 

Derivatives of phenylethanolamine substituted by a phenolic hydroxyl on the para position have been known for some time to exhibit 0-adrenergic agonist activity. As a consequence of this property, the compounds have proven useful as bronchodilators for the treatment of asthma (see Chapter 3). Since such sympathomimetic drugs tend to have undesired activity on the cardiovascular system in addition to the desired activity on the bronchii, considerable work has been devoted to the preparation of compounds that would show selectivity for the adrenergic receptors (02> that predominate in the lung. Attachment of the side chain to a heterocyclic aromatic phenol has been one avenue that has shown promise for achieving this selectivity. 

Metaproterenol (Alupent, Metaprel) [Bronchodilator/Beta Adrenergic Agonist] Uses Asthma rev ible bronchospasm Action Sympathomimetic bronchodilator Dose AduUs. Inhal 1-3 inhal q3-4h, 12 inhal max/24 h wait 2 min between inhal PO 20 mg q6-8h Peds. Inhal 0.5 mg/kg/dose, 15 mg/dose max inhaled q4-6h by neb or 1-2 puffs q4-6h PO 0.3-0.5 mg/kg/dose... 

The answer is e. (Hardman, p 215.) Ritodrine hydrochloride is a selective P2-adrenergic agonist that relaxes uterine smooth muscle. It also has the other effects attributable to p-adrenergic receptor stimulants, such as bronchodilation, cardiac stimulation, enhanced renin secretion, and hyperglycemia. 

Metaproterenol (Alupent, Metaprel) [Bronchodilator/ Beta-Adrenergic Agonist] Uses Asthma reversible bronchospasm Action Sympathomimetic bronchodilator Dose Adults. Neb 0.2-0.3 mL in 2.5-3.0 mL of NS Peds. Neb 0.1-0.2 mL/kg of a 5% soln in 2.5 mL NS Caution [C, /-] Contra Tach, other arrhythmias Disp Aerosol 0.65 mg/inhal soln for inhal 0.4, 0.6% tabs 10, 20 mg syrup 10 mg/5 mL SE Nervousness, tremors (common), tach, HTN Interactions T Effects W/ sympathomimetic drugs, xanthines T risk of arrhythmias W/ cardiac glycosides, halothane, levodopa, theophylline, thyroid hormones T HTN W/ MAOIs effects W/ BBs EMS Separate additional aerosol use by 5 min fewer 3i effects than isoproterenol longer-acting monitor lung sounds before/after administration... 

Respiratory smooth-muscle cells contain the beta-2 subtype of adrenergic receptors.76 (See Chapter 18 for a discussion of adrenergic receptor classifications.) Stimulation of these beta-2 receptors results in relaxation of bronchiole smooth muscle. Lienee, drugs that stimulate these beta-2 adrenergic receptors (i.e., beta-adrenergic agonists) produce bronchodilation and can be used to prevent or inhibit airway obstruction in bronchospastic diseases.22,99... 

Onset and duration of bronchodilation effects of inhaled adrenergic agonists. 

Pj-selective adrenergic agonists that induce bronchodilation through activation of adenylate cyclase, causing an increase in cyclic AMP levels and resulting in smooth muscle relaxation in the airvvays. 

Administering sympathomimetics (beta-adrenergic agonists) Sympathomimetics promote the production of cyclic AMP, which cause bronchodilation. 

Drugs used as bronchodilators include the P-adrenergic agonists, caffeine, and theophylline. Pharmacokinetic details of some bronchodilators are summarized in Table 33-3. 

P Adrenergic agonists, such as albuterol, bitolterol, isoproterenol, metaproterenol, pirbuterol, and terbutaline in the inhaled form, have become the treatment of choice for a short-acting approach to relief of asthma. These drugs are very effective at providing rapid bronchodilation without significant cardiac or systemic effects. Because they are administered in the vapor form, have short time of action, and produce little toxicity, measurement of blood levels offers little clinical benefit patient response provides a convenient form of monitoring therapy. 

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