Respiratory - Pharmacology

Question 1

1st generation H1 blockers

• Examples
• Mechanism
• Clinical use
• Toxicity

Answer 1

• Examples
  
  • Diphenhydramine, dimenhydrinate, chlorpheniramine.
  • Names contain “-en/-ine” or “-en/-ate.”
• Mechanism
  
  • Reversible inhibitors of H1 histamine receptors.
• Clinical use
  
  • Allergy, motion sickness, sleep aid.
• Toxicity
  
  • Sedation, antimuscarinic, anti-α-adrenergic.

Question 2

2nd generation H1 blockers

• Examples
• Mechanism
• Clinical use
• Toxicity

Answer 2

• Examples
  
  • Loratadine, fexofenadine, desloratadine, cetirizine.
  • Names usually end in “-adine.”
• Mechanism
  
  • Reversible inhibitors of H1 histamine receptors.
• Clinical use
  
  • Allergy.
• Toxicity
  
  • Far less sedating than 1st generation because of decreased entry into CNS.

Question 3

Guaifenesin

• Mechanism

Answer 3

• Mechanism
  
  • Expectorant
  • Thins respiratory secretions
  • Does not suppress cough reflex.

Question 4

N-acetylcysteine

• Mechanism
• Clinical use

Answer 4

• Mechanism
  
  • Expectorant / mucolytic
• Clinical use
  
  • Can loosen mucous plugs in CF patients.
  • Also used as an antidote for acetaminophen overdose.

Question 5

Dextromethorphan

• Mechanism
• Toxicity

Answer 5

• Mechanism
  
  • Antitussive (antagonizes NMDA glutamate receptors).
  • Synthetic codeine analog.
• Toxicity
  
  • Has mild opioid effect when used in excess.
  • Naloxone can be given for overdose.
  • Mild abuse potential.

Question 6

Pseudoephedrine, phenylephrine

• Mechanism
• Clinical use
• Toxicity

Answer 6

• Mechanism
  
  • Sympathomimetic α-agonistic nonprescription nasal decongestants.
• Clinical use
  
  • Reduce hyperemia, edema, and nasal congestion
  • Open obstructed eustachian tubes.
  • Pseudoephedrine also illicitly used to make methamphetamine.
• Toxicity
  
  • Hypertension.
  • Can also cause CNS stimulation/anxiety (pseudoephedrine).

Question 7

Asthma drugs (614)

Answer 7

• Bronchoconstriction is mediated by…
  
  • (1) inflammatory processes
  • (2) parasympathetic tone
• Therapy is directed at these 2 pathways.

Question 8

Albuterol (614)

• Type of drug
• Mechanism
• Clinical use

Answer 8

• Type of drug
  
  • Asthma drug: β2-agonist
• Mechanism
  
  • Relaxes bronchial smooth muscle (β2).
• Clinical use
  
  • Use during acute exacerbation.

Question 9

Salmeterol, formoterol (614)

• Type of drug
• Mechanism
• Clinical use
• Toxicity

Answer 9

• Type of drug
  
  • Asthma drugs: β2-agonists
• Mechanism
  
  • Long-acting agents
• Clinical use
  
  • For prophylaxis
• Toxicity
  
  • Adverse effects are tremor and arrhythmia.

Question 10

Theophylline (614)

• Type of drug
• Mechanism
• Clinical use
• Toxicity

Answer 10

• Type of drug
  
  • Asthma drug: Methylxanthine
• Mechanism
  
  • Likely causes bronchodilation by inhibiting phosphodiesterase –>Ž increased cAMP levels due to decreased cAMP hydrolysis.
  • Metabolized by cytochrome P-450.
  • Blocks actions of adenosine.
• Clinical use
  
  • Usage is limited because of narrow therapeutic index
• Toxicity
  
  • Cardiotoxicity, neurotoxicity

Question 11

Ipratropium (614)

• Type of drug
• Mechanism
• Clinical use

Answer 11

• Type of drug
  
  • Asthma drug: Muscarinic antagonist
• Mechanism
  
  • Competitive block of muscarinic receptors
• Clinical use
  
  • Prevents bronchoconstriction
  • Also used for COPD

Question 12

Tiotropium (614)

• Type of drug
• Mechanism
• Clinical use

Answer 12

• Type of drug
  
  • Asthma drug: Muscarinic antagonist
• Mechanism
  
  • Long-acting
• Clinical use
  
  • Used for COPD

Question 13

Beclomethasone, fluticasone (614)

• Type of drug
• Mechanism
• Clinical use

Answer 13

• Type of drug
  
  • Asthma drugs: Corticosteroids
• Mechanism
  
  • Inhibit the synthesis of virtually all cytokines.
  • Inactivate NF-κB, the transcription factor that induces the production of TNF-α and other inflammatory agents.
• Clinical use
  
  • 1st-line therapy for chronic asthma.

Question 14

Montelukast, zafirlukast (614)

• Type of drug
• Mechanism
• Clinical use

Answer 14

• Type of drug
  
  • Asthma drugs: Antileukotrienes
• Mechanism
  
  • Block leukotriene receptors.
• Clinical use
  
  • Especially good for aspirin-induced asthma

Question 15

Zileuton (614)

• Type of drug
• Mechanism

Answer 15

• Type of drug
  
  • Asthma drug: Antileukotriene
• Mechanism
  
  • A 5-lipoxygenase pathway inhibitor
  • Blocks conversion of arachidonic acid to leukotrienes.

Question 16

Omalizumab (614)

• Type of drug
• Mechanism
• Clinical use

Answer 16

• Type of drug
  
  • Asthma drug
• Mechanism
  
  • Monoclonal anti-IgE antibody.
  • Binds mostly unbound serum IgE and blocks binding to FcεRI.
• Clinical use
  
  • Used in allergic asthma resistant to inhaled steroids and long-acting β2-agonists.

Question 17

Methacholine

• Mechanism
• Clinical use

Answer 17

• Mechanism
  
  • Muscarinic receptor agonist.
• Clinical use
  
  • Used in bronchial provocation challenge to help diagnose asthma.

Question 18

Bosentan

• Mechanism
• Clinical use

Answer 18

• Mechanism
  
  • Competitively antagonizes endothelin-1 receptors
  • Decreases pulmonary vascular resistance.
• Clinical use
  
  • Used to treat pulmonary arterial hypertension.