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1、Chapter 35Lecture 11,Drugs for Common Upper Respiratory Infections,Respiratory Tract,Upper respiratory tract includes:nares,nasal cavity,pharynx,and larynx.Lower respiratory tract includes:trachea,bronchi,bronchioles,alveoli,and alveolar-capillary membraneAir enters the upper resp.tract&travels to t
2、he lower tract where gas exchange takes place,Respiratory Tract,Respiration=the process whereby gas exchange occurs at the alveolar-capillary membrane.3 phases:1.Ventilation-movement of air from the atmosphere through the upper&lower airways to the alveoli 2.Perfusion-blood from the pulmonary circul
3、ation is adequate at the alveolar-capillary bed 3.Diffusion-molecules move from area of higher concentration to lower concentration of gases-O2 passes into the capillary bed to be circulated&CO2 leaves the capillary bed&diffuses into the alveoli for vent.excretion,Respiratory Tract,Perfusion-influen
4、ced by alveolar pressure.For gas exchange,the perfusion of each alveoli must be matched by adequate ventilation.Mucosal edema,secretions,&bronchospasms increase the resistance to airflow&dec.ventilation&diffusion of gasesBronchial Smooth Muscle-In the tracheobronchial tube is smooth muscle whose fib
5、ers spiral around the tube contraction constriction of airway-Parasympathetic Nervous system releases acetylcholine bronchoconstriction-Sympathetic Nervous system releases epinephrine stimulates beta-2 receptors in bronchial smooth muscle bronchodilation,Drugs for Upper respiratory Infections,Upper
6、Respiratory Infections(URIs)=common cold,acute rhinitis,sinusitis,acute tonsillitis,acute laryngitis-The common cold=most expensive$500 million spent on OTC preparationsCommon Cold&Acute Rhinitis-Common cold caused by the rhinovirus&affects primarily the nasopharyngeal tract.-Acute rhinitis(inflamma
7、tion of mucus membranes of nose)usually accompanies the common cold-Allergic rhinitis-caused by pollen or a foreign substance,Drugs for Upper Respiratory Infections,Incubation period of a cold=1 to 4 days before onset of symptoms&first 3 days of the cold-Home remedies=rest,chicken soup,hot toddies,V
8、itamins-4 groups of drugs used to manage symptoms=antihistamins(H-1 blocker),decongestants(sympathomimetic amines),antitussives,expectorants,Drugs for Upper Respiratory Infections-Antihistamines,Antihistamines or H-1 blockers-compete w/histamine for receptor sites prevents a histamine response.2 typ
9、es of histamine receptors-H-1&H-2 H-1 stimulation=extravascular smooth muscles(including those lining nasal cavity)are constricted H-2 stimulation=an inc.in gastric secretions=peptic ulcer disease Do not confuse the 2 receptors-antihistamines decrease nasopharyngeal secretions by blocking the H-1 re
10、ceptor,Drugs for Upper Respiratory Infections-antihistamines,Histamines-A compound derived from an amino acid histadine.Released in response to an allergic rxn(antigen-antibody rxn)-such as inhaled pollen-When released it reacts w/H-1 receptors=arterioles&capillaries dialate=inc.in bld flow to the a
11、rea=capillaries become more permeable=outward passage of fluids into extracellular spaces=edema(congestion)=release of secretions(runny nose&watery eyes)-Large amts.of released histamine in an allergic rxn=extensive arteriolar dilation=dec.BP,skin flushed&edematous=itching,constriction&spasm of bron
12、chioles=SOB&lg.amts.of pulmonary&gastric secretions,Drugs for Upper Respiratory Infections-Antihistamines,Astemizole(Hismanal),Cetirizine(Zertec),Loratadine(Claritin),Chlorpheniramine(Chlortrimeton),Diphenhydramine(Benadryl)Actions=competitive antagonist at the histamine receptor;some also have anti
13、cholinergic propertiesUses=Treat colds;perennial/seasonal allergic rhinitis(sneezing,runny nose);allergic activity(drying some are also antiemeticSE=Drowsiness,dizziness,sedation,drying effectsCI=glaucoma,acute asthma,Drugs for Upper Respiratory Infections-Decongestants,Nasal congestion results from
14、 dilation of nasal bld.vessels d/t infection,inflammation,or allergy.With dilation theres transudation of fluid into tissue spaces swelling of the nasal cavityDecongestants(sympathomimetic amines)-stimulate alpha-adrenergic receptor vasoconstriction of capillaries w/in nasal mucosa shrinking of the
15、nasal mucus membranes&reduction in fluid secretion(runny nose),Drugs for Upper Respiratory Infections-Decongestants,Naphazoline HCL(Allerest),Pseudoephedrine(Actifed,Sudafed),Oxymetolazone(Afrin),Phenylpropanolamine HCL(Allerest,Dimetapp)Use-Congestion d/t common cold,hayfever,upper resp.allergies,s
16、inusitisSE=Jittery,nervous,restless,Inc BP,inc.bld.sugarCI=Hypertension,cardiac disease,diabetesPreparations=nasal spray,tablets,capsules,or liquidFrequent use,esp.nasal spray,can result in tolerance&rebound nasal congestion-d/t irritation of nasal mucosa,Drugs for Upper Respiratory Infections-Intra
17、nasal Glucocorticoids,Beclomethasone(Beconase,Vancenase,Vanceril),Budesonide(Rhinocort),Dexamethasone(Decadron)fluticasone(Flonase)-Action-steroids used to dec.inflammation locally in the nose-Use-Perennial/seasonal allergic rhinitis(sneezing,runny nose)-May be used alone or w/antihistamines-SE-rare
18、,but w/continuous use dryness of the nasal mucosa may occur,Drugs for Upper Respiratory Infections-Antitussives,Action-Acts on the cough control center in the medulla to suppress the cough reflexUse-Cough suppression for non-productive irritating coughs*Codeine-Narcotic analgesic to control a cough
19、d/t the common cold or bronchitis*Dextromethorphan-nonnarcotic antitussive that suppresses the cough center in the medulla,widely used-syrup,liquid,chewable&lozenges-SE=drowsiness,sedation,Drugs for Upper Respiratory infections-Expectorants,Action-Loosens bronchial secretions so they can be eliminat
20、ed w/coughing*A nonproductive cough becomes more productive and less frequentUses-Nonproductive coughsGuaifenesin(Robitussin)=Most common*Use alone or in combo w/other resp.drugsHydration is the best expectorant,Chapter 36,Drugs for Acute and ChronicLower Respiratory Disorders,Drugs for Lower Respir
21、atory Disorders,Lung Compliance-Lung volume based on the unit of pressure in the alveoli*Determines the lungs ability to stretch(tissue elasticity)*Determined by:connective tissue;surface tension in the alveoli controlled by surfactant-surfactant lowers surface tension in alveoli&prevents interstiti
22、al fluid from entering*Inc.(high)lung compliance in COPD*Dec.(low)lung compliance in restrictive pulmonary disease=lungs become“stiff”&need more pressure,Drugs for Lower Respiratory Disorders,Chronic obstructed pulmonary disease(COPD)&restrictive pulmonary disease=2 major lower resp.tract diseasesCO
23、PD=airway obstruction w/inc.airway resistance to airflow to lung tissues-4 causes-Chronic bronchitis-emphysema-Bronchiectasis-asthma*Above frequently result in irreversible lung tissue damage.Asthma reversible unless frequent attacks and becomes chronic.,Drugs for Lower Respiratory Disorders,Restric
24、tive lung disease=a dec.in total lung capacity as a result of fluid accumulation or loss of elasticity of the lung.*Causes:Pulmonary edema,pulmonary fibrosis,pneumonitis,lung tumors,scoliosisBronchial Asthma=10-12 million people of all ages affected-a chronic obstructive pulmonary disease characteri
25、zed by periods of bronchospasm resulting in wheezing&difficulty in breathing,Drugs for Lower Respiratory Disorders,Asthma-Bronchospasm or bronchoconstriction results when the lung tissue is exposed to extrinsic or intrinsic factors that stimulate a bronchoconstrictive response-Causes:humidity,air pr
26、essure changes,temp.changes,smoke,fumes,stress,emotional upset,allergies,dust,food,some drugs*Pathophys=Mast cells(found in connective tissue throughout the body)are directly involved in the asthmatic response-esp.to extrinsic factors-allergens attach themselves to mast cells&basophils=antigen-antib
27、ody rxn,Drugs for Lower Respiratory Disorders-Asthma,Mast cells stimulate release of chemical mediators(histamines,cytokines,serotonin,ECF-A(eosinophils)These chemical mediators stimulate bronchial constriction,mucous secretions,inflammation,pulmonary congestionCyclic adenosine monophosphate(cAMP)-a
28、 cellular substance responsible for maintaining bronchodilation-When inhibited by histamines&ECF-A bronchoconst.Sympathomimetic(adrenergic)bronchodilators inc.amt.of cAMP&promote dilation first line drugs used,Drugs for Lower Respiratory Disorders,Sympathomimetics:Alpha&Beta-2 Adrenergic AgonistsInc
29、rease cAMP dilation of bronchioles in acute bronchospasm caused by anaphylaxis from allergic rxn give nonselective epinephrine(Adrenalin)-SQ in an emergency to promote bronchodilation&inc.BP SE=tremors,dizziness,HTN,tachycardia,heart palpitations,anginaFor bronchospasm d/t COPD-selective beta-2 adre
30、nergic agonists are given via aerosol or tablet,Drugs for Lower Respiratory Disorders,Metaproterenol(Alupent,Metaprel)-some beta-1,but primarily used as a beta-2 agent-PO or inhaler/nebulizer-For long-term asthma Rx beta-2 adrenergic agonists frequently given by inhalation*more drug delivered direct
31、ly to constricted bronchial site*Effective dose less than PO dose&less side effects-Action=relaxes bronchial smooth muscle-onset=fast-SE=Nervousness,tremors,restlessness,insomnia&inc.HR,Drugs for Lower Respiratory Disorders,Albuterol(Proventil,Ventolin)-More beta-2 selective-PO or inhaler-Used for a
32、cute/chronic asthma-Rapid onset of action&longer duration than Metaproterenol-Fewer SE because more beta-2 specific,but high doses can still effect beta-1 receptors&cause nervousness,tremors&inc.pulse rate,Drugs for Lower Respiratory Disorders-Anticholinergics,Ipratropium bromide(Atrovent)-Action-co
33、mpetitive antagonist(inhibits)of cholinergic receptors in bronchial smooth muscle=bronchiole dilation-Inhaler-Use-In combination w/beta agonist for asthma If using Atrovent w/an inhaled steroid or cromolyn,use Atrovent 5 min.before the steroid or cromolyn-bronchioles dilate&drugs more effective,Drug
34、s for Lower Respiratory Disorders-Methylxanthine derivatives,Aminophylline,Theophylline(TheoDur),Caffeine*PO or IV-*Use-Treatment of asthma also-diuresis,cardiac,CNS&gastric acid stimulation*When given IV a low therapeutic index&range-Monitor levels frequently*PO doses can be given in standard dosag
35、es*Avoid smoking,caffeine&inc.fluid intake,Methylxanthine derivatives,Drug Interactions:Inc the risk of dig toxicity,decreases the effects to lithium,dec theophyllin levels with Dilantin,theophyllin and beta-adrenergic agonist given together-synergistic effect can occurcardiac dysrhythmias.Beta bloc
36、kers,Tagamet,Inderal and e-mycin decrease the liver metabolism rate and inc.the half-life and effects of theophyllin SE:Anorexia,N&V,nervousness,dizziness,palpitations,GI upset&bleeding,HA,restlessness,flushing,irritability,marked hypotension,hyper-reflexia and seizures.CI:Severe cardiac dysrhythmia
37、s,hyperthyroidism,peptic ulcer disease(increases gastric secretions),Drugs for Lower Respiratory Disorders-Leukotrine Receptor Antagonists&Synthesis Inhibitors,Leukotriene(LT)a chemical mediator that can cause inflammatory changes in the lung.The group cysteinyl leukotrienes promotes and inc in eosi
38、nophil migration,mucus production,and airway wall edema,which result in broncho-constriction.LT receptor antagonists< synthesis inhibitors(Leukotriene modifiers)effective in reducing the inflammatory symptoms of asthma triggered by allergic&environmental stimuli-Not for acute asthma,Leucotriene re
39、ceptor antagonist and synthesis inhibitors,Zafirlukast(Accolate),Zileuton(Zyflo),Montelukast sodium(Singulair)PO Action-Decreases the inflammatory process Use-prophylactic&maintenance drug therapy for asthmaAccolate 1st in group,leukotriene receptor antagonist reduce inflammation&dec bronchoconstric
40、tion,PO-BID-rapidly absorbedSingulair New leukotriene receptor antagonist,short t1/2(2.5-5.5)Safe for children under 6yo.,Drugs for Lower Respiratory Disorders-Glucocorticoids(Steroids),Glococorticoids have an anti-inflammatory action and are used if asthma is unresponsive to bronchodilator therapyG
41、iven:inhaler-beclomethasone(Vanceril,Beclovent);tablet-triamcinolone(Amcort,Aristocory),dexamethasone(Decadron),prednisone;injection-dexamethasone,hydrocortisoneSE significant w/long-term oral use-fluid retention,hyperglycemia,impaired immune responseIrritating to the gastric mucosa-take w/foodWhen
42、d/cing taper the dosage slowly,Drugs for Lower Respiratory Disorders-Cromolyn&Nedocromil,Cromolyn(Intal)-for prophylactic Rx of bronchial asthma&must be taken on a daily basis-NOT used for acute asthma-Inhaler*Action-inhibits the release of histamine that can cause an asthma rxn*SE-mouth irritation,
43、cough&a bad taste in the mouth*Caution-rebound bronchospasm is a serious side effect do not d/c the drug abruptlyNedocromil sodium-action&uses similar to Intal-prophylactic usage-inhalation therapy-may be more effective than Intal,Drugs for Lower Respiratory Disorders-Mucolytics,Acetylcysteine(Mucom
44、yst)-nebulization*Action-liquefies&loosens thick mucous secretions so they can be expectorated*Use-dissolves thick mucous,acetaminophen overdose(bonds chemically to reduce liver damage)*SE-N&V,chest tightness,bronchoconstriction*Use w/a bronchodilatorDornase alfa(Pulmozyme)-an enzyme that digests the DNA in thick sputum of cystic fibrosis(CF)clients,MATH,NDC 000w-7293-01 VIAL No.7293 R/X Lilly ADD-Vantage Vial NEBCIN Tobramycin sulfate injection,usp,60 Mg per 6ml,You need to prepare 30 mg.How much solution will you need?,30 mg X 6 ml=60 mg,1 X 6 ml=2,6=3 ml 2,
