Classification of Bronchodilators and Mechanism of Action

Classification of Bronchodilators

• Beta2 Agonists:
  • Short-acting: salbutamol, terbutaline
  • Long-acting: salmeterol, formoterol
• Anticholinergics:
  • Short-acting: ipratropium
  • Long-acting: tiotropium, aclidinium
• Methylxanthines:
  • Theophylline
• Combination Therapy:
  • Beta2 agonist + anticholinergic
  • Beta2 agonist + corticosteroid

Mechanism of Action

• Beta2 Agonists:
  • Stimulate beta2 receptors, increasing cAMP, leading to smooth muscle relaxation
• Anticholinergics:
  • Block muscarinic receptors, decreasing acetylcholine activity, leading to smooth muscle relaxation
• Methylxanthines:
  • Inhibit phosphodiesterase, increasing cAMP, leading to smooth muscle relaxation

Therapeutic Uses

• Asthma:
  • Quick relief: short-acting beta2 agonists
  • Long-term control: long-acting beta2 agonists, anticholinergics, and corticosteroids
• Chronic Obstructive Pulmonary Disease (COPD):
  • Symptomatic relief: anticholinergics and long-acting beta2 agonists
  • Combination therapy: anticholinergics + beta2 agonists or corticosteroids

Adverse Effects

• Beta2 Agonists:
  • Tremors, anxiety, tachycardia, hypokalemia
• Anticholinergics:
  • Dry mouth, urinary retention, constipation
• Methylxanthines:
  • Nausea, vomiting, diarrhea, insomnia, seizures

Classification of Bronchodilators

• Beta2 agonists are classified into short-acting (salbutamol, terbutaline) and long-acting (salmeterol, formoterol) types
• Anticholinergics are classified into short-acting (ipratropium) and long-acting (tiotropium, aclidinium) types
• Methylxanthines include theophylline
• Combination therapy involves combining beta2 agonists with anticholinergics or corticosteroids

Mechanism of Action

• Beta2 agonists stimulate beta2 receptors, increasing cAMP, leading to smooth muscle relaxation
• Anticholinergics block muscarinic receptors, decreasing acetylcholine activity, leading to smooth muscle relaxation
• Methylxanthines inhibit phosphodiesterase, increasing cAMP, leading to smooth muscle relaxation

Therapeutic Uses

• Short-acting beta2 agonists are used for quick relief in asthma
• Long-acting beta2 agonists, anticholinergics, and corticosteroids are used for long-term control in asthma
• Anticholinergics and long-acting beta2 agonists are used for symptomatic relief in COPD
• Combination therapy is used in COPD, involving anticholinergics + beta2 agonists or corticosteroids

Adverse Effects

• Beta2 agonists can cause tremors, anxiety, tachycardia, and hypokalemia
• Anticholinergics can cause dry mouth, urinary retention, and constipation
• Methylxanthines can cause nausea, vomiting, diarrhea, insomnia, and seizures