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34 Cards in this Set

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Vasomotor center and direct stimulation tends to

Raise BP

Vagal stimulation and direct vasodilation tends to:

Lower BP


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

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)

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

Functions of Adenosine

1.) Dilate cerebral blood vessels


2.) Inhibit gastric secretions


3.) Smooth muscle contraction especially bronchial


4.) Depress cardiac pacemaker

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



Factors that need dose reduction while using theophylline

1.) CHF


2.) Pneumonia


3.) Liver disease


4.) Age greater than 60yrs

Drugs which induce Theophylline metabolism therefore decreasing its plasma concentration

1.) Charcoal broiled meat


2.) Smoking


3.) Rifampicin


3.) Phenytoin

Drugs that inhibit Theophylline metabolism therefore increasing its plasma concentration:

1.) Oral contraceptives


2.) Allopurinol


3.) Erythromycin


4.) Cimetidine


5.) Ciprofloxacin

Theophylline enhances the effects of:

1.) Furosemide


2.) Digitalis


3.) Sympathomimetics


4.) Oral anticoagulants


5.) Hypoglycemics

Theophylline decreases the effects of:

1.) Phenytoin


2.) Lithium

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

Anticholinergics: examples and function

1.) Ipratropium bromide


2.) Tiotropium bromide



* they cause bronchodilation by blocking cholinergic constrictor tone

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

Leukotriene Antagonists

1.) Montelukast


2.) Zafirlukast



* both are in aspirin induced asthma and exercise induced asthma

Montelukast & Zarfilukast antagonize cyst LT1 receptor mediated:

1.) Bronchoconstriction


2.) Increased vascular permeability


3.) Recruitment of eoainophils

Mast cell Stabilizers

1.) Cromolyn sodium


2.) Nedocromil sodium



* inhibit degranulation of mast cells

Function of Mast cell Stabilizers:

1.) Inhibit chemotaxis


2.) Decrease cellular inflammatory response


3.) Decrease antigen induced bronchial hyper reactivity

Corticosteroid benefit by:

1.) Reduce bronchial hyperreactivity


2.) Reducing mucosal oedema


3.) Suppressing inflammatory reaponse to AG: AB reaction or other trigger stimuli


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

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

Inhaled Steroids

1.) Beclomethasone diproprionate


2.) Budesonide


3.) Fluticasone


4.) Ciclesonide

Steroid withdrawal may manifest as:

1.) Precipitation of asthma


2.) Muscular pain


3.) Lassitude


4.) Depression


5.) Hypotension

Systemic efdects of long term inhaled glucocorticoids are clunically relevant only at doses greater than

600ug/day

Systemic side effects 9f corticosteroids:

Adrenal suppression


Cushingoid changes


Growth retardation


Xataracts


Osteoporosis


CNS effects


Bruising

Side effects of inhaled corticosteroids:

Dysphonia


Hoarseness of voice


Sore throat


Oropharyngeal candidiasis


Omalizumab

It neutralizes free IgE in circulation without activating inflammatory cells

Delmucents MOA

They reduce afferent impulses from the inflamed/irritated pharyngeal mucosa

Expectorants MOA

Increase bronchial secretion or reduce its viscosity facilitating its removal by coughing


Examples: Sodium & Potassium citrate

Bromhexine

Potent mucolytic and mucokinetic capabale of inducing thin copoious bronchial secretion

MOA of Bromhexine

It depolymerises mucopolysacharrides directly as well as by liberating lysosomal enzymes therefore network of fibres in tenacious sputum is broken

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

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