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22 Cards in this Set
- Front
- Back
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Rau Pharmacology |
Rau Workbook chapter 7 70 to 72 |
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Mode of action of anticholinergic agents in blocking muscarinic receptors in the airway to inhibit cholinergic induced bronchoconstriction |
M1, M3 are the most inportant receptors in the anticholinergic process, M1 is on the postganglionic and the M3 receptor is directly on the bronchial smooth muscle |
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Mode of action |
Vagally mediated reflex; bronchoconstriction :Irritant aerosols, cold air, high flows, smoke, fumes, histamine release :afferent impulse to CNS = reflex cholinergic |
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Pharmacological effects |
Anticholinergic (antimuscarinic agents) :Respiratory tract :CNS :Eyes :gastrointestinal :Genitourinary |
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Adverse Effects |
No change: BP, EKG, or HR No increase ventilation to perfusion abnormalities V/Q abnormalities No tolerance/loss of protection Side effects of ipratropium bromide :dry mouth (most common) :Mydriasis (eyes should be protected) :SVN: also pharyngitis, dyspnea, flulike symptoms, bronchitis, upper respiratory infection
Tachyphylaxys, become tolerant to the sympathomimetic Sympathomimetics can increase perfusion, blood flow to the lung, but there will be a temp decrease O2 sat. |
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Box 32-2 isde effects seen with anticholinergic aerosol agents |
SVN, MDI, DPI |
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Clinical application (describe the graph showing albuterol. ipratropim and duoneb, duneb is best |
Use in COPD :More potent bronchodilators than Beta adrenergics in emphysema/bronchitis :FDA approved specifically for COPD :Tiotropium maintains higher PFT levels than ipratropium |
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Clinical application |
Use in asthma :No label indication for asthma in US :Antimuscarinics not effect in asthma :May be useful in ::nocturnal asthma ::psychogenic asthma ::asthmatics being treated for another condition with Beta blockers ::As an alternative to theophylline ::In acute/severe episodes not responding to Beta agonist
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Combination therapy |
Beta adrenergic and anticholinergic agents in COPD :Additive effect of Beta agonists and anticholinergis ::Mean peak increases :::31 to 33% for combined drugs :::24 to 25% for ipratropium alone :::24 to 27% for albuterol alone |
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Administration of drugs, adrenergic and anticholinergic |
Sequence of administration :No data to support either drug being administered first :Not an issue when using Combivent :Beta agonist may be given first becuase ::More rapid onset ::Distributed in large and small airways
Quiz on thursday with be over adrenergics and anticholinergics End here and Quiz |
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Clinical indications for use of Xanthines |
Use in Asthma :Theophylline: maintenance therapy (step 2 or higher) of mild, persistent asthma :Is a phosphodiasteres inhibitor :Side effects and narrow therapeutic index may make it a poor choice versus other agents
Use in COPD Theophylline: recommended by GOLD as an alternative to Beta 2 agonist and anticholinergics
Use in apnea of prematurity (due to an undeveloped brainstem, they get apnea) :First line treatment :Theophylline is most often used, but caffeine citrate may be better choice (safer, higher therapeutic index (QUIZ)
cyclic 3-5 amp relaxes peripheral and bronchial smooth muscle |
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Specific Xanthine Agents |
AKA methylxanthines Found as alkaloids in plant species Theophylline :Tea leaves Theobromine :Cocoa seeds or beans Caffeine :Coffee beans and kola nuts :Cocoa seeds or beans :Tea leaves
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Pharamcological Properties of Xanthines |
Effects :CNS stimulation (good for infants with apnea of prematurity) :Cardiac muscle stimulation :Diuresis :Bronchial, uterine, and vascular smooth muscle relaxation ::Theophylline is classified as a bronchodilator :Peripheral and coronary vasodilation :Cerebral vasoconstriction ::Used in headache remedies |
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Pharamcological properties of Xanthines |
Structure: activity relations :Thophylline ::Methyl attachments at N:1 and N:3 enhance bronchodilation/increase side effects :Caffeine ::Additional methyl group at N:7 decreases bronchodilation :Dyphylline ::Derivative of theophylline with methyl attachment at N:7 that weakens bronchodilation :Enprofylline ::Not available in US ::potent bronchodilator ::Large substitution of N:3 position |
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Pharmacological properties of Xanthines |
Proposed theories of activity :Exact mechanism of action unknown ::Smooth muscle relaxation via inhibition of phosphodiesterase Theophylline latches on to cyclic 3,5 amp and prevents phosphodiesterase from inactivating cyclic 3,5 amp
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Titrating theophylline Doses |
Individuals metabolize theophylline at different rates Equivalent doses of theophylline salts :Anhydrous theophylline = 100% theophylline :Salts of theophylline not pure by weight |
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Serum levels of theophylline |
less than 5 micrograms/ml no effects 10 to 20 is the therapeutic range greater than 20 is nausea greater than 20 is cardiac arrhythmias 40 to45 is seizures |
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Asthma |
5 to 15 micromgrams per ml
COPD 10 to 12 micrograms per ml
Dosage schedules :used to titrate drug levels :Rapid theophyllization ::5 mg/kg lean body weight oral loading dose of anhydrou theophylline
Each 5 mg/kg = 1 microgram per ml serum level
SLow titration :16 mg /kl 23 hour or 400 mg / 24 hours(whichever is lless |
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Factors affecting theorphylline |
Conditions affecting liver/kidneys INterations with other drugs Conditions that increase theophylline levels :viral hepatitis :Left ventricular failure (pulmonary edema) Condition that decrease theophylline levels :Smoking Additive effect :Beta agonists
ARDS is non cardiogenic respiratory failure |
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Clinical uses |
Asthma :use debated :only after other relievers and controllers have failed
COPD :if ipratropium bromide and beta 2 agonists fail to provide control |
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Nonbronchodilating effects of theophylline |
Increase in force of respiratory muscle contractility Increase respiratory muscle endurance Increase ventilatory drive :Increase cardiac output :Decreased pulmonary vascular resistance Antiinflammatory effects
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Use in apnea of prematuring |
Xanthines are the first line choice when nonpharmacological methods unsuccessful Caffeine citrate is substitued for theophylline :Loading dose is 20 mg/kg :daily maintenance dose of 5 mg/kg |
