Lower Respi

• Bronchodilators


  Facilitate respiration by dilating the airways
• Bronchodilators


  • For symptomatic relief or prevention of bronchial asthma and bronchospasm associated with COPD
  • Some are administered orally and absorbed systematically
  • Other medications are administered directly into airways by nebulizers
• Types of bronchodilators


  • Xanthines
  • Sympathomimetics (beta-agonists)
  • Anticholinergics
  • Inhaled steroids
• Xanthines


  • Were once the primary choice for treatment of asthma and bronchospasm
  • Have relatively narrow margin of safety and interact with many other drugs
  • No longer considered the first-choice bronchodilators
• Xanthines


  • Aminophyline
  • Caffeine
  • Dyphilline
  • Oxytriphylline
  • Pentoxyfilline
  • Theophylline
• Mechanism of action of xanthines


  1. Direct effect on the smooth muscles of the respiratory tract, both those on the bronchi and the blood vessels

  2. Stimulate the CNS and respiration, dilate coronary and pulmonary arteries, and diuresis

  3. Exact MOA is not known
• Theophylline Toxicity
• Drugs that enhance the metabolism of xanthines


  Nicotine, barbiturates, carbamazepine, phenytoin, rifampicin
• Drugs that decrease the metabolism of xanthines


  Cimetidine, quinolones, macrolides, hormonal contraceptives
• Sympathomimetics


  • Mimic the effects of the sympathetic nervous system
  • Dilation of the bronchi and increased rate and depth of respiration
• Sympathomimetic bronchodilators


  • Albuterol
  • Bitolterol
  • Isoproterenol
  • Metaproterenol
• Other sympathomimetic bronchodilators


  • Ephedrine
  • Epinephrine
• Mechanism of action of sympathomimetics

  1. Increase the concentration of cellular cAMP (Cyclic adenosine monophosphate) leading to dilation of the bronchioles

  2. Other systemic effects include: increased blood pressure, increased heart rate, vasoconstriction, decreased renal and GI blood flow
• Inhaled steroids


  • Very effective treatment for bronchospasm
  • Do not cause direct bronchodilation
  • Decrease the inflammatory response in the airway