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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. Bronchodilators β receptor agonists
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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.
Antiasthmatic Drugs • Bronchodilators • β receptor agonists • Theophylline • Muscarinic antagonists • Anti-inflammatory agents • Steroids • Anti-leukotriene agents • Anti-allergic agents • Stabilizer of inflammatory cell membrane • H1 receptor blocker
intermediate- acting long-acting Beta Adrenoceptor Agonists • Adrenaline: α,β agonist • Ephedrine: α,β agonist • Isoprenaline:β1 ,β2 agonist • β2-selective agonists • Salbutamol: • Terbutaline : • Clenbuterol: • Formoterol: • Salmeterol: • Bambuterol:
• 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 inthis medication guide.
Adverse Reactions of β2 agonists: • Skeletal muscle tremor • Cardiac effect: tachycardia, arrhymias • Metabolism disturbance: ketone bodies↑, acidosis, [K+]o↓
BRONCHODILATORS • Theophylline
Theophylline • Methylxanthine derivatives. • Mechanism of Action:
Clinical Use: • Asthma: maintenance treatment • Chronic obstructive pulmonary disease (COPD) • Central sleep apnea (CSA) • Adverse Reactions: • Narrow margin of safety. Toxic effects are related to its plasma concentrations. • Gastrointestinal distress, tremor, and insomnia. • Cardiac arrhythmias, convulsions → lethal.
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.
Ketotifen • H1 receptor blocker. • Prevent and inverse down-regulation of β2-receptor.
Common agents: • zafirlukast and montelukast: LTD4-receptor antagonists • zileuton: 5-lipoxygenase inhibitor
Routes of administration: • Systemic administration: including oral and injection. More severe toxicity. • Inhalation: • Common inhalant GCs: • FP, BDP, BUD, TAA, FNS
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