Respiratory

Question 1

H1 Blockers

First Generation

Answer 1

Reversible inhibitors of H1 histamine receptors

Diphenydramine, dimenhydrinate, chlorpheniramine

Clinical Uses: Allergy, motion sickness, sleep aid

Toxicity: Sedation, antimuscarininc, anti-alpha-adrenergic

Question 2

H1 Blockers

Second Generation

Answer 2

Reversible inhibitors of H1 histamine receptors

Loratadine, fexofenadine, desloratadine, cetirizine

Clinical Uses: Allergy

Toxicity: Far less sedating than 1st generation because of decreased entry into CNS

Question 3

Expectorants

Guaifenesin

Answer 3

Thins respiratory secretions

Does not suppress cough reflex

Question 4

Expectorants

N-acetylcysteine

Answer 4

Mucolytic, can loosen mucous plugs in CF patients by disrupting disulfide bonds.

Also used as an antidote for acetaminophen overdose

Question 5

Dextromethorphan

Answer 5

Antitussive (antagonizes NMDA glutamate receptors)

Synthetic codeine analgog.

Has mild opiod effect when used in excess

Naloxone can be given for overose, midl abuse potential

May cause serotinin syndrome if combined with other serotonergic agents

Question 6

Pseudoephedrine

Phenylephrine

Answer 6

Mechanism: alpha-adrenergic agonists, used as nasal decongestants

Clinical use: reduce hyperemia, edema, nasal congestions; open obstructed eustachian tubes. Pseudoephedrine also illicitly used to make methamphetamine

Toxicity: HTN, can also cause CNS stimulation/anxiety (pseudoephedrine)

Question 7

Pulmonary Hypertension Drugs

Endothelin receptor antagonists

Answer 7

Include bosentan

Competetively antagonize endothelin-1 receptors which decreases pulmonary vascular resistance

Hepatotoxic (monitor LFTs)

Question 8

Pulmonary Hypertension Drugs

PDE-4 Inhibitors

Answer 8

Include sildenafil

Inhibit cGMP PDE5 and prolong vasodilatory effect of NO

Also used to treat erectile dysfunction

Question 9

Pulmonary Hypertension Drugs

Prostacyclin analogs

Answer 9

Include epoprostenol, iloprost

Prostacyclins (PGI2) with direct vasodilatory effects on pulmonary and systemic arterial vascular beds.

Inhibit platelet aggregation

Side effects: flushing, jaw pain

Question 10

Asthma Drugs

B2-agonists

Answer 10

Albuterol: relaxes bronchial smooth muscle (B2), used during acute exacerbation

Salmeterol, formoterol: long-acting agents for prophylaxis. Afverse effects are tremor and arrhythmia

Question 11

Asthma Drugs

Corticosteroids

Answer 11

Fluticasone, budesonide: inhibit the synthesis of virtually all cytokines

Inactivates NF-kB (the transcription factor that induces production of TNF-alpha and other inflammatory agents)

First line therapy for chronic asthma

Question 12

Asthma Drugs

Muscarinic Antagonists

Answer 12

Ipratropium: competitivel blocks muscarininc receptors, preventing bronchoconstriction. Also used for COPD

Tiotropium is long acting

Question 13

Asthma Drugs

Antileukotrienes

Answer 13

Montelukast, zafirlukast: block leukotriene receptors (CysLT1), especially good for ASA-induced asthma

Zileuton: 5-lipoxygenase pathway inhibitor, blocks conversion of arachidonic acid to leukotrienes, hepatotoxic

Question 14

Asthma Drugs

Omalizumab

Answer 14

Monoclonal anti-IgE antibody

Binds mostly unbound serum IgE and blocks binding to FceRI

Used in allergic asthma resistant to inhaled steroids and long acting B2-agonists

Question 15

Asthma Drugs

Methylxanathines

Answer 15

Theophylline

Likely causes bronchodilation by inhibiting phosphodiesterase which increases cAMP levels due to decreased cAMP hydrolysis

Usage is limited because of narrow therapeutic indecy (cardiotoxicity, neurotoxicity)

Metabolized by cytochrome P-450

Blocks actions of adenosine

Question 16

Asthma Drugs

Methacholine

Answer 16

Muscarinic receptor (M3) agonist

Used in bronchial challenge test to help diagnose asthma