Respiratory

Question 1

H1 blockers - 1st generation

Answer 1

Diphenhydramine, dimenhydrinate, chlorpheniramine, Hydroxyzine, Promethazine, Meclizine

Reversible inhibition of H1 histamine receptors

CLINCAL USES: Allergy, motion sickness, sleep aid

TOXICITY: Drowsy-sedation, antimuscarinic, anti-alpha-adrenergic, anti-serotonergic (appetite stimulation)

Question 2

H1 blockers - 2nd generation

Answer 2

Loratadine, fexofenadine, desloratadine, cetirizine

Question 3

B2 - agonoists

Answer 3

Asthma drugs - bronchoconstriction is mediated by (1) inflammatory processes and (2) parasympathetic tone; therapy is directed at these 2 pathways.

Albuterol - relaxes bronchial smooth muscle (B2). Use during acute exacerbation - rescue inhaler

Salmeterol, formoterol - long-acting agents for prophylaxes. Adverse effects are tremor and arrhythmia.

Question 4

Methylxanthines

Answer 4

Theophylline - likely causes bronchodilation by inhibiting phosphodiesterase, therebye increasing cAMP levels by decreasing cAMP hydrolysis.

TOXICITY: Usage is limited due to narrow therapeutic index (cardiotoxicity, neurotoxicity (OD = seizures, tachyarrhytmia, abd pain, N/V/D. Do gastric lavage, give activated charcoal to reduce Abs, Cathartics to inc GI elimination, B-blockers for the heart, and Benzo’s/Barbituates for seizures).

**Methylxanthines are similar to caffeine. Both have mild cortical arousal and insomnia with low doses.

Question 5

Muscarinic antagonists

Answer 5

Ipratropium - competitive block of muscarinic receptors (M3), preventing bronchoconstriction. Also used for COPD, as is tiotropium, a long-acting muscarinic antagonist.

Question 6

Corticosteroids

Answer 6

Beclomethasone, fluticasone, flunisolide

Inhibit the synthesis of virtually all cytokines. Inactivate NF-kB, the transcription factor that induces the production of TNF-alpha, among other inflammatory agents. 1st-line therapy for chronic asthma. (prevention of s/s and maintaining pulmonary function)

TOXICITY: May cause oral candidiasis; use spacer and oral rinsing

May also see increased IOP, cataracts, growth retardation, bone loss, HPA axis suppression

Question 7

Antileukotrienes

Answer 7

Monolukast, zafirlukast - block leukotriene receptors. Especially good for aspirin-induced asthma. (In which ASN inhibits COX –> inc leukotriene synthesis due to shunting of arachidinic acid to 5- lipoxygenase

Question 8

Omalizumab

Answer 8

(Asthma drug) Monoclonal anti-IgE antibody. Binds mostly unbound serum IgE (Does not bind IgE already bound to mast cell FCERI receptor; will not degranulate mast cells)

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

Question 9

Cromolyn

Answer 9

(Asthma drug). Inhibits mast cell degranulation for asthma prophylaxis. Acts independently of any stimuli present, 2nd line for allergic rhinitis and bronchial asthma. (Less effective than corticosteroids).

Question 10

Nedocromil

Answer 10

(Asthma drug). Inhibits mast cell degranulation for asthma prophylaxis. Acts independently of any stimuli present, 2nd line for allergic rhinitis and bronchial asthma. (Less effective than corticosteroids).

Question 11

Guaifenesin

Answer 11

Guaifenesin For anything with mucus buildup - chronic bronchitis, CF, pneumonia, etc

Expectorant - thins respiratory secretions; does not suppress cough reflex

Question 12

N-acetylcysteine

Answer 12

N-acetylcysteine

Mucolytic - can loosen plugs in CF patients. (splits disulfide bonds linking the protein in mucous)

Also used as an antidote for acetaminophen overdose. (Binds NAPQI (toxic) and increases glutathione reserves in the body.)

Also used to prevent radiocontrast-nduced nephropathy in patients with renal insufficiency.

Question 13

Bosentan

Answer 13

Used to treat pulmonary arterial hypertension. Competitively antagonizes endothelin-1 receptors, decreasing pulmonary vascular resistance. (Endothelin binding usually causes vasoconstriction)

Question 14

Dextromethorphan

Answer 14

Antitussive (antagonizes NMDA glutamate receptors). Synthetic codeine analog. Has mild opioid effect when used in excess.

Naloxone can be given for overdose. Mild abuse potential.

Question 15

Pseudoephedrine, phenylephrine

Answer 15

Pseudoephedrine, phenylephrine

MECHANISM: Sympathomimetic alpha-antagonist nonprescription nasal decongestants. (vasoconstrict nasal vessels)

CLINICAL USE: Reduce hyperemia, edema, and nasal congestion; open obstructed eustachian tubes. Pseudoephedrine also used as a stimulant.

TOXICITY: Hypertension. Can also cause CNS stimulation/anxiety.

Tachyphylaxis after >3 days of consecutive use -> Rebound rhinorrhea due to decreased endogenouse NE production from nasal nerve terminals.

–> stop topical nasal decongestants periodically to allow restoration of normal NE feedback pathways. p564 of 2013 FA

Question 16

Xymetazoline, oxymetazoline

Answer 16

Xylometazoline, oxymetazoline

MECHANISM: Sympathomimetic alpha-antagonist nonprescription nasal decongestants. (vasoconstrict nasal vessels)

CLINICAL USE: Reduce hyperemia, edema, and nasal congestion; open obstructed eustachian tubes.

TOXICITY: Hypertension.

Tachyphylaxis after >3 days of consecutive use -> Rebound rhinorrhea due to decreased endogenouse NE production from nasal nerve terminals.

Question 17

Methacholine

Answer 17

Muscarinic receptor agonist. Used in asthma challenge testing; it binds M3. Hypersensitive asthmatics will have severe bronchoconstriction, normals will have mild bronchoconstriction.

Question 18

Ephedrine

Answer 18

Releases stored endogenous catecholamines (indirect sympathomimetic) for nasal congestion.