Clinical pharmacology of drugs acting on the respiratory organs function

Bronchial asthma Bronchial asthma is a disease caused by increased responsiveness of the tracheobronchial tree to various stimuli.

Bronchial asthma (cont’d)

Antiasthmatic Drugs I. Bronchodilators 1. β receptor agonists 2. Theophylline 3. Muscarinic antagonists II. Anti-inflammatory agents 1. Steroids 2. Anti-leukotriene agents III. Anti-allergic agents 1. Stabilizer of inflammatory cell membrane 2. H 1 receptor blocker

Beta Adrenoceptor Agonists Adrenaline: α,β agonist Adrenaline: α,β agonist Ephedrine: α,β agonist Ephedrine: α,β agonist Isoprenaline ： β 1,β 2 agonist Isoprenaline ： β 1,β 2 agonist β 2 -selective agonists β 2 -selective agonists Salbutamol: Salbutamol: Terbutaline : Terbutaline : Clenbuterol: Clenbuterol: Formoterol: Formoterol: Salmeterol: Salmeterol: Bambuterol: Bambuterol: intermediate- acting long-acting

BRONCHODILATORS

Salmeterol is a bronchodilator. It works by relaxing muscles in the airways to improve breathing. Salmeterol inhalation is used to prevent asthma attacks. It will not treat an asthma attack that has already begun. Salmeterol inhalation is also used to treat chronic obstructive pulmonary disease (COPD) including emphysema and chronic bronchitis. Salmeterol inhalation may also be used for conditions other than those listed in this medication guide.

Adverse Reactions of β 2 agonists: Adverse Reactions of β 2 agonists: 1) Skeletal muscle tremor 2) Cardiac effect: tachycardia, arrhymias 3) Metabolism disturbance: ketone bodies ↑, acidosis, [K + ] o ↓

BRONCHODILATORS Theophylline

Theophylline Methylxanthine derivatives. Methylxanthine derivatives. Mechanism of Action: Mechanism of Action:

Clinical Use: Clinical Use: 1. Asthma: maintenance treatment 2. Chronic obstructive pulmonary disease (COPD) 3. Central sleep apnea (CSA) Adverse Reactions: Adverse Reactions: Narrow margin of safety. Toxic effects are related to its plasma concentrations. Narrow margin of safety. Toxic effects are related to its plasma concentrations. Gastrointestinal distress, tremor, and insomnia. Gastrointestinal distress, tremor, and insomnia. Cardiac arrhythmias, convulsions → lethal. Cardiac arrhythmias, convulsions → lethal.

Muscarinic Antagonists

BRONCHODILATORS

Anticholinergic Drugs

Anti-inflammatory Agents

Anti-allergic Agents Madiators release inhibitors. No bronchodialator action but can prevent bronchoconstriction caused by a challenge with antigen to which the patient is allergic.

The Cromones: Cromolyn & Nedocromil

Ketotifen H1 receptor blocker. Prevent and inverse down-regulation of β 2 - receptor.

Anti-leukotriene agents

Common agents: Common agents: I. zafirlukast and montelukast: LTD 4 - receptor antagonists II. zileuton: 5-lipoxygenase inhibitor

Glucocorticoids (GCs)

Corticosteroids

Routes of administration: Routes of administration: Systemic administration: including oral and injection. More severe toxicity. Systemic administration: including oral and injection. More severe toxicity. Inhalation: Inhalation: Common inhalant GCs: Common inhalant GCs: FP, BDP, BUD, TAA, FNS FP, BDP, BUD, TAA, FNS

Corticosteroids

Step-wise approach to the treatment of asthma according to recent guidelines. LTRA, leukotriene receptor antagonist; SR, slow release. The dose of inhaled corticosteroids refers to beclomethasone dipropionate