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34 Cards in this Set
- Front
- Back
Vasomotor center and direct stimulation tends to |
Raise BP |
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Vagal stimulation and direct vasodilation tends to: |
Lower BP |
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Effects of Methyl xanthines in CVS |
* Directly stimulate the heart and increase force of myocardial contractions * Tachycardia is more common with Theophylline * Theophylline dilates systemic blood vessels by direct action, reducing peripheral resistance |
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Effects if Methyl Xanthines on Skeletal Muscle |
1.) Caffeine enhances contractile power of skeletal muscles 2.) It increases release of Ca2+ from sarcoplasmic reticulum 3.) Increases Ach release: central action relieves fatigue and increases muscular work 4.) Theophylline produces diaphragmatic contractility (helpful in cases of dyspnoea) |
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MOA of Methylxanthines |
1.) Release of Ca2+ from sarcoplasmic reticilum 2.) Inhibition of phosphodiesterase which degrades cyclic nucleotides increasing CAMP levels: PDE inactivate CAMP & CGMP which are 2nd messengers that mediate bronchial smooth muscle relaxation 3.) Blockade od adenosine receptors |
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Functions of Adenosine |
1.) Dilate cerebral blood vessels 2.) Inhibit gastric secretions 3.) Smooth muscle contraction especially bronchial 4.) Depress cardiac pacemaker |
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Theophylline |
well absorbed orally 50% bound to plasma protein crosses the placenta metabolized in the liver by demethylation and oxidation elimination half-life varies with age
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Factors that need dose reduction while using theophylline |
1.) CHF 2.) Pneumonia 3.) Liver disease 4.) Age greater than 60yrs |
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Drugs which induce Theophylline metabolism therefore decreasing its plasma concentration |
1.) Charcoal broiled meat 2.) Smoking 3.) Rifampicin 3.) Phenytoin |
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Drugs that inhibit Theophylline metabolism therefore increasing its plasma concentration: |
1.) Oral contraceptives 2.) Allopurinol 3.) Erythromycin 4.) Cimetidine 5.) Ciprofloxacin |
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Theophylline enhances the effects of: |
1.) Furosemide 2.) Digitalis 3.) Sympathomimetics 4.) Oral anticoagulants 5.) Hypoglycemics |
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Theophylline decreases the effects of: |
1.) Phenytoin 2.) Lithium |
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Functions of Theophylline in Asthma & COPD |
1.) Bronchodilation 2.) Decrease release of inflammatory mediators 3.) Increase mucociliary clearance 4.) Stimulate respiratory drive 5.) Augment diaphragmatic contractility: useful in premature infants with apnoea |
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Anticholinergics: examples and function |
1.) Ipratropium bromide 2.) Tiotropium bromide * they cause bronchodilation by blocking cholinergic constrictor tone |
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Airway effects of released Ach are mediated via activation of 3 receptors: |
1.) M1: in parasympathetic ganglia, mucous glands and alveolar walls 2.) M2 (autoinhibitory): in parasympathetic nerve terminals E.) M3: in airway smooth muscle, mucus glands and airway epithelium |
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Leukotriene Antagonists |
1.) Montelukast 2.) Zafirlukast * both are in aspirin induced asthma and exercise induced asthma |
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Montelukast & Zarfilukast antagonize cyst LT1 receptor mediated: |
1.) Bronchoconstriction 2.) Increased vascular permeability 3.) Recruitment of eoainophils |
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Mast cell Stabilizers |
1.) Cromolyn sodium 2.) Nedocromil sodium * inhibit degranulation of mast cells |
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Function of Mast cell Stabilizers: |
1.) Inhibit chemotaxis 2.) Decrease cellular inflammatory response 3.) Decrease antigen induced bronchial hyper reactivity |
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Corticosteroid benefit by: |
1.) Reduce bronchial hyperreactivity 2.) Reducing mucosal oedema 3.) Suppressing inflammatory reaponse to AG: AB reaction or other trigger stimuli
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MOA of Corticosteroids: |
1.) Corticosteroids traverse cell membranes and bind to specific cytoplasmic receptor 2.) Steroid-receptor complex translocates to the cell nucleus where it attaches to nuclear binsing sites and initiates synthesis of mRNA 3.) New proteins formed exert a variety of effects on cellular functions |
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Actions of Corticosteroids: |
1.) Inhibition of cytokine and mediator release 2.) Attenuation of mucus secretion 3.) Upregulation of b-adrenoceptor numbers 4.) Inhibition of of IgE synthesis 5.) Attenuation of eicosanoid generation |
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Inhaled Steroids |
1.) Beclomethasone diproprionate 2.) Budesonide 3.) Fluticasone 4.) Ciclesonide |
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Steroid withdrawal may manifest as: |
1.) Precipitation of asthma 2.) Muscular pain 3.) Lassitude 4.) Depression 5.) Hypotension |
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Systemic efdects of long term inhaled glucocorticoids are clunically relevant only at doses greater than |
600ug/day |
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Systemic side effects 9f corticosteroids: |
Adrenal suppression Cushingoid changes Growth retardation Xataracts Osteoporosis CNS effects Bruising |
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Side effects of inhaled corticosteroids: |
Dysphonia Hoarseness of voice Sore throat Oropharyngeal candidiasis |
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Omalizumab |
It neutralizes free IgE in circulation without activating inflammatory cells |
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Delmucents MOA |
They reduce afferent impulses from the inflamed/irritated pharyngeal mucosa |
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Expectorants MOA |
Increase bronchial secretion or reduce its viscosity facilitating its removal by coughing Examples: Sodium & Potassium citrate |
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Bromhexine |
Potent mucolytic and mucokinetic capabale of inducing thin copoious bronchial secretion |
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MOA of Bromhexine |
It depolymerises mucopolysacharrides directly as well as by liberating lysosomal enzymes therefore network of fibres in tenacious sputum is broken |
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MOA of Acetylcysteine |
Opens disulfude bonds in mucoproteuns present in sputum and makes it less viscid-has to be administered directly into the respiratory tract |
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MOA of Antitussives |
They act in the CNS to rause the threshold of cough center OR They act peripherally in the respiratory tract to reduce tussal impulses |