Anti-asthmatic

• Mechanisms of action of antiasthmatic agents

  1. Release of histamine from mast cells

  2. Epinephrine and albuterol forming complexes with β receptors

  3. Xanthines blocking the enzyme phosphodiesterase
• All three mechanisms

  Result in promotion of smooth muscle relaxation in the small airways
• Histamine–H1 receptor complexes


  Promote a signal transduction pathway in which inositol triphosphate (IP3) and diacylglycerol (DAG), both second messengers, are induced and promote smooth muscle contraction
• Epinephrine and albuterol forming complexes with β receptors


  Induce adenyl cyclase activity such that cyclic adenosine monophosphate (cAMP) is synthesized; this second messenger blocks smooth muscle contraction
• Xanthines blocking the enzyme phosphodiesterase


  Result in prolonged lifetimes of cAMP, allowing it to function for prolonged periods in blocking smooth muscle contraction
• Types of medication

  • Bronchodilators
  • Anti-inflammatory
• Bronchodilators

  • Short-acting B2-agonists
  • Antimuscarinics
  • Xanthines
• Anti-inflammatory


  • Long acting B2 agonists
  • Glucocorticoids (steroids)
  • Leukotriene receptor antagonists
  • Mast cell stabilizers
• Short-acting B2-Agonists


  • Inhibit mediator release from mast cells
  • Increase mucus clearance
• Types of Short-acting B2-Agonists


  • Non-selective B2-Agonist
  • Selective B2-Agonists
• Non-selective B2-Agonist


  • Stimulate both beta-1 (heart) and beta-2 (smooth muscle) receptors
  • Increased heart rate and other sympathetic effects occur in addition to bronchodilation
  • Tachycardia and arrhythmias
• Non-selective B2-Agonists


  • Epinephrine
  • Isoproterenol
  • Metaproterenol
• Selective B2-Agonists


  • Drug of choice for acute attacks of asthma
  • Cause bronchodilation without tachycardia
• Selective B2-Agonists


  • Salbutamol (Ventolin)
  • Terbutaline
• Antimuscarinics


  • Less effective than B2 agonists
  • Antagonize binding of acetylcholine to muscarinic receptors (promotes contraction of airway smooth muscle and increase mucous secretion)
• Antimuscarinics


  • Ipratropium (Atrovent)
  • Tiotropium
• Xanthines/Methylxanthines


  • Purine derivatives
  • Phosphodiesterase inhibitor
  • Inhibit the bronchoconstrictive action of adenosine and activate histone deacetylases which may result in decreases in the transcription of proinflammatory genes
  • Inhibit the release of proinflammatory agents, like HISTAMINE, from a variety of inflammatory cells
  • Used for primary apnea of prematurity
  • Initially administered intravascularly then orally
  • Crosses the placenta (teratogenic)
• Xanthines/Methylxanthines

  • Caffeine (coffee)
  • Theobromine (cocoa)
  • Theophylline (tea)
• Beta-2 Adrenoreceptor Agonists (Long-acting, Selective)


  • Used for nocturnal asthma
  • May increase the risk of a severe asthma attack, unless they are used in combination with an inhaled corticosteroid
• Beta-2 Adrenoreceptor Agonists (Long-acting, Selective)


  • Salmeterol
  • Formoterol: higher affinity for B2-adrenoceptors; efficacy is higher
  • Indacaterol: currently approved only for COPD
• Glucocorticoids (Steroids)


  • Mechanism of action: inhibits the enzyme phospholipase A2 (precursor of leukotrienes, prostaglandins, platelet activating factor)
  • Used alone or combined with beta-agonists
• Types of Glucocorticoids (Steroids)


  • Inhaled corticosteroids
  • Systemic corticosteroids
• Inhaled corticosteroids


  • First-line therapy for persistent asthma in adults and children
  • Examples: Beclomethasone, Budesonide, Flunisolide, Fluticasone
• Systemic corticosteroids


  • Travel throughout the body before reaching the airway
  • Results in more side effects and more serious side effects than with inhaled corticosteroids
  • Considered as a first-line treatment for acute asthma exacerbations
• Oral systemic corticosteroids


  • Prednisone: synthetic anti-inflammatory glucocorticoid derived from cortisone; biologically inert and converted to PREDNISOLONE in the liver
  • Prednisolone
  • Methylprednisolone
  • Betamethasone: can weaken immune system; not indicated if patient has fungal infection
  • Dexamethasone: treat many different inflammatory (e.g. allergic disorders, skin conditions, ulcerative colitis, arthritis, lupus, psoriasis, or breathing disorders)
  • Hydrocortisone: also a treatment for urticaria
• Parenteral systemic corticosteroids


  • Triamcinolone (kenalog): intramuscular
• Leukotriene Receptor Antagonists


  • Zafirlukast: for treatment of chronic asthma
  • Montelukast: prevent wheezing, difficulty breathing, chest tightness, and coughing caused by asthma; treat symptoms of seasonal and perennial allergic rhinitis (HAY FEVER)
  • Pranlukast: more effective in patients with moderate or severe asthma who are not treated with oral steroids
• Mast Cell Stabilizers


  Mechanism of action: Interferes with the antigen-antibody reaction to release mast cell mediators; Inhibits mast cell degranulation (release of inflammatory mediators in response to specific antigens)
• Mast Cell Stabilizers


  • Cromolyn: Indicated for asthma that is triggered by exercise, exposure to cold air, and environmental agents; Has some efficacy in preventing food allergy
  • Nedocromil