上呼吸道感染药物治疗-PPT课件.ppt

1、Chapter 35Lecture 11Drugs for Common Upper Respiratory Infections Respiratory TractUpper 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 & tr

2、avels to the 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 fro

3、m the pulmonary circulation 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. excretionResp

4、iratory Tract Perfusion - influenced 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 gases Bronchial Smooth Muscle - In the t

5、racheobronchial tube is smooth muscle whose fibers 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 bronchodil

6、ationDrugs for Upper respiratory Infections Upper Respiratory Infections (URIs) = common cold, acute rhinitis, sinusitis, acute tonsillitis, acute laryngitis - The common cold = most expensive $500 million spent on OTC preparations Common Cold & Acute Rhinitis - - Common cold caused by the rhinoviru

7、s & affects primarily the nasopharyngeal tract. - Acute rhinitis (inflammation of mucus membranes of nose) usually accompanies the common cold - Allergic rhinitis - caused by pollen or a foreign substanceDrugs for Upper Respiratory Infections Incubation period of a cold = 1 to 4 days before onset of

8、 symptoms & first 3 days of the cold - Home remedies = rest, chicken soup, hot toddies, Vitamins - 4 groups of drugs used to manage symptoms = antihistamins (H-1 blocker), decongestants (sympathomimetic amines), antitussives, expectorants Drugs for Upper Respiratory Infections - Antihistamines Antih

9、istamines or H-1 blockers - compete w/ histamine for receptor sites prevents a histamine response. 2 types 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

10、ulcer disease Do not confuse the 2 receptors - antihistamines decrease nasopharyngeal secretions by blocking the H-1 receptorDrugs for Upper Respiratory Infections - antihistamines Histamines - A compound derived from an amino acid histadine. Released in response to an allergic rxn (antigen-antibody

11、 rxn) - such as inhaled pollen - When released it reacts w/ H-1 receptors = arterioles & capillaries dialate = inc. in bld flow to the area = capillaries become more permeable = outward passage of fluids into extracellular spaces= edema (congestion) = release of secretions (runny nose & watery eyes)

12、 - Large amts. of released histamine in an allergic rxn = extensive arteriolar dilation = dec. BP, skin flushed & edematous = itching, constriction & spasm of bronchioles = SOB & lg. amts. of pulmonary & gastric secretions Drugs for Upper Respiratory Infections - Antihistamines Astemizole (Hismanal)

13、, Cetirizine (Zertec), Loratadine (Claritin), Chlorpheniramine (Chlortrimeton), Diphenhydramine (Benadryl) Actions = competitive antagonist at the histamine receptor; some also have anticholinergic properties Uses = Treat colds; perennial/seasonal allergic rhinitis (sneezing, runny nose); allergic a

14、ctivity (drying & sedation); some are also antiemetic SE = Drowsiness, dizziness, sedation, drying effects CI = glaucoma, acute asthmaDrugs for Upper Respiratory Infections - Decongestants Nasal congestion results from dilation of nasal bld. vessels d/t infection, inflammation, or allergy. With dila

15、tion theres transudation of fluid into tissue spaces swelling of the nasal cavity Decongestants (sympathomimetic amines) - stimulate alpha-adrenergic receptor vasoconstriction of capillaries w/in nasal mucosa shrinking of the nasal mucus membranes & reduction in fluid secretion (runny nose)Drugs for

16、 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, sinusitis SE = Jittery,nervous,restless, Inc BP, inc. b

17、ld. sugar CI = Hypertension, cardiac disease, diabetes Preparations = nasal spray, tablets, capsules, or liquid Frequent use, esp. nasal spray, can result in tolerance & rebound nasal congestion - d/t irritation of nasal mucosaDrugs for Upper Respiratory Infections - Intranasal Glucocorticoids Beclo

18、methasone (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,

19、 but w/ continuous use dryness of the nasal mucosa may occurDrugs for Upper Respiratory Infections - Antitussives Action - Acts on the cough control center in the medulla to suppress the cough reflex Use - Cough suppression for non-productive irritating coughs * Codeine - Narcotic analgesic to contr

20、ol a cough 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, sedationDrugs for Upper Respiratory infections - Expectorants Action - Loosens bronchial secr

21、etions so they can be eliminated w/ coughing * A nonproductive cough becomes more productive and less frequent Uses - Nonproductive coughs Guaifenesin (Robitussin) = Most common * Use alone or in combo w/ other resp. drugs Hydration is the best expectorantChapter 36Drugs for Acute and ChronicLower R

22、espiratory DisordersDrugs for Lower Respiratory 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

23、lowers surface tension in alveoli & prevents interstitial fluid from entering * Inc. (high) lung compliance in COPD * Dec. (low) lung compliance in restrictive pulmonary disease = lungs become “stiff” & need more pressureDrugs for Lower Respiratory Disorders Chronic obstructed pulmonary disease (COP

24、D) & restrictive pulmonary disease = 2 major lower resp. tract diseases COPD = 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

25、 unless frequent attacks and becomes chronic.Drugs for Lower Respiratory Disorders Restrictive 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, scoliosis Bronchia

26、l Asthma = 10-12 million people of all ages affected - a chronic obstructive pulmonary disease characterized by periods of bronchospasm resulting in wheezing & difficulty in breathingDrugs for Lower Respiratory Disorders Asthma - Bronchospasm or bronchoconstriction results when the lung tissue is ex

27、posed to extrinsic or intrinsic factors that stimulate a bronchoconstrictive response - Causes: humidity, air pressure changes, temp. changes, smoke, fumes, stress, emotional upset, allergies, dust, food, some drugs * Pathophys = Mast cells (found in connective tissue throughout the body) are direct

28、ly involved in the asthmatic response - esp. to extrinsic factors - allergens attach themselves to mast cells & basophils = antigen-antibody rxn Drugs for Lower Respiratory Disorders - Asthma Mast cells stimulate release of chemical mediators (histamines, cytokines, serotonin, ECF-A (eosinophils) Th

29、ese chemical mediators stimulate bronchial constriction, mucous secretions, inflammation, pulmonary congestion Cyclic adenosine monophosphate (cAMP) - a cellular substance responsible for maintaining bronchodilation - When inhibited by histamines & ECF-A bronchoconst. Sympathomimetic (adrenergic) br

30、onchodilators inc. amt. of cAMP & promote dilation first line drugs usedDrugs for Lower Respiratory Disorders Sympathomimetics: Alpha & Beta-2 Adrenergic Agonists Increase cAMP dilation of bronchioles in acute bronchospasm caused by anaphylaxis from allergic rxn give nonselective epinephrine (Adrena

31、lin) - SQ in an emergency to promote bronchodilation & inc. BP SE = tremors, dizziness, HTN, tachycardia, heart palpitations, angina For bronchospasm d/t COPD - selective beta-2 adrenergic agonists are given via aerosol or tabletDrugs for Lower Respiratory Disorders Metaproterenol (Alupent, Metaprel

32、) - 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 directly to constricted bronchial site * Effective dose less than PO dose & less side effects - Action = relaxes b

33、ronchial 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 acute/chronic asthma - Rapid onset of action & longer duration than Metaprotere

34、nol - Fewer SE because more beta-2 specific, but high doses can still effect beta-1 receptors & cause nervousness, tremors & inc. pulse rateDrugs for Lower Respiratory Disorders - Anticholinergics Ipratropium bromide (Atrovent) - - Action - competitive antagonist (inhibits) of cholinergic receptors

35、in bronchial smooth muscle = bronchiole dilation - Inhaler - Use - In combination w/ beta agonist for asthma & for bronchospasm associated w/ COPD - Need to teach clients how to use properly: If using Atrovent w/ a beta-agonist, use beta-agonist 5 min. before Atrovent; If using Atrovent w/ an inhale

36、d steroid or cromolyn, use Atrovent 5 min. before the steroid or cromolyn - bronchioles dilate & drugs more effective Drugs for Lower Respiratory Disorders - Methylxanthine derivatives Aminophylline, Theophylline (TheoDur), Caffeine * PO or IV - * Use - Treatment of asthma & COPD* Action - Inc. cAMP

37、 bronchodilation; 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 dosages* Avoid smoking, caffeine & inc. fluid intakeMethylxanthine derivatives Drug Interactions: Inc the risk of d

38、ig toxicity, decreases the effects to lithium,dec theophyllin levels with Dilantin, theophyllin and beta-adrenergic agonist given together - synergistic effect can occurcardiac dysrhythmias. Beta blockers, Tagamet, Inderal and e-mycin decrease the liver metabolism rate and inc. the half-life and eff

39、ects 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 dysrhythmias, hyperthyroidism, peptic ulcer disease (increases gastric secretions)Drugs for

40、 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 eosinophil migration, mucus production, and airway wall edema, which result

41、 in broncho-constriction. LT receptor antagonists & LT synthesis inhibitors (Leukotriene modifiers) effective in reducing the inflammatory symptoms of asthma triggered by allergic & environmental stimuli - Not for acute asthmaLeucotriene receptor antagonist and synthesis inhibitorsZafirlukast (Accol

42、ate), 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 bronchoconstriction, PO-BID-rapidly absorbedSingulair New leu

43、kotriene 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 therapy Given: inhaler- beclomethasone (Vanceri

44、l, Beclovent); tablet - triamcinolone (Amcort, Aristocory), dexamethasone (Decadron), prednisone; injection - dexamethasone, hydrocortisone SE significant w/ long-term oral use - fluid retention, hyperglycemia, impaired immune response Irritating to the gastric mucosa - take w/ food When d/cing tape

45、r the dosage slowlyDrugs 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 ir

46、ritation, cough & a bad taste in the mouth * Caution - rebound bronchospasm is a serious side effect do not d/c the drug abruptly Nedocromil sodium - action & uses similar to Intal - prophylactic usage - inhalation therapy - may be more effective than IntalDrugs for Lower Respiratory Disorders - Muc

47、olytics Acetylcysteine (Mucomyst) - 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 bronchodi

48、lator Dornase alfa (Pulmozyme) - an enzyme that digests the DNA in thick sputum of cystic fibrosis (CF) clientsMATHNDC 000w-7293-01 VIAL No. 7293 R/X Lilly ADD-Vantage Vial NEBCIN Tobramycin sulfate injection, usp 60 Mg per 6mlYou need to prepare 30 mg. How much solution will you need?30 mg X 6 ml = 60 mg 1 X 6 ml = 26 = 3 ml 2