Respiratory Pharmacology Flashcards
How do beta 2 adrenoceptor agonist reduce histamine release?
-Histamine release involves influx of Ca2+ ions.
-A raised cAMP reduces the permeability of cell membranes to Ca2+ ions.
-Beta 2 adrenoceptor agonists stimulate cAMP synthesis
=reduces histamine release
What causes bronchoconstriction?
Result from release of ACh, histamine & inflammatory mediators
When you are ‘run down’ what happens to your WBCs?
The stress hormone cortisol inhibits WBCs & reduce inflammation causing you to become ill.
What is the effect of histamine causing vasodilation to occur?
The release of histamine causes vasodilation on local tissues. This vasodilation is needed to release WBCs (they can now move through the gaps in the capillaries created from vasodilation)
What number is the vagus nerve?
Number 10
What does ipratropium bromide do?
It’s an anti musclarinic. It inhibits the parasympathetic nervous system, causing bronchodilation.
Why are antihistamines e.g. IV periton used for heart burn?
There are H2 receptors in the stomach, which produces HCL, which can cause heart burn.
What is the effect of adrenaline?
Works on beta 2 receptors, causing bronchodilation & vascoconstriction.
Why can oedemisis of the larynx occur as a result of shock?
Shock is an inadequate tissue perfusion due to a lowering of BP. You can lose a lot of fluid out of blood vessels, go into shock. Can have oedema of airways, as fluid accumulates around larynx (oedemisis tissue around larynx & stop breathing).
What is the effect of prolonged exposure to airway irritants?
Chronic inflammation
What is the main side effect of corticosteroids esp preventer inhalers e.g. beclamethasone
Oral thrush (candidiasis of mouth)
Name a preventer & reliever inhaler.
- Preventer (brown)- beclamethasone. It prevents inflammation from taking place or keeps inflammation under control.
- Reliever (blue) (short-acting bronchodilators) -ventalin
What type of drug is prednisolone?
Oral steroids
What enables you to breath out?
Lung elasticity
What would a sign be that a person has lost the elasticity in there lungs?
Use of accessory muscles; costal recession, tracheal tug, supraclavicular recession & abdominal breathing
What is lung compliance?
The elasticity of the lungs
What causes loss of the tissue contributing to elasticity?
Smoking & long term exposure to irritants
What does airway inflammation cause?
- hyper secretion of mucus
- airway muscle constriction (bronchoconstriction)
- swelling of bronchial membranes
What does a spirometery do?
Measures lung volume & capacity
What does FEV stand for?
Forced expiratory volume
What is a symbicort turbuhaler?
Combination of anti inflammatory & bronchodilator
What’s another name for ipratropium bromide?
Atrovent
What is chronic bronchitis?
- A condition caused by chronic respiratory irritation, inflammation
- characterised by increased secretions & infection
- expectorate (cough up) = green mucus & temp - ?chest infection ?pneumonia
How is emphysema characterised?
Characterised by destruction of alveoli, laboured respiratory gas exchange & SOB
What is asthma?
- An inflammatory disease if respiratory passageways
- characterised by bronchoconstriction, SOB & wheezing
What is extrinsic asthma?
If the attack has an ALLERGIC basis
What is INTRINSIC asthma?
If there is NO allergic basis.
What are the 4 inflammatory mediators of the respiratory tract?
- histamine
- prostaglandins & leukotrienes
- eosinophilic chemotactic factor of anaphylaxis (ECF-A)
- slow reacting substance of anaphylaxis (SRS-A)
How is bronchiolar smooth muscle relaxed?
Stimulation of beta-2 adrenergic receptors.
How is bronchiolar smooth muscle contracted?
Stimulation of cholinergic receptor (musclarinic)
What does cholinergic mean?
A nerve cell where ACh is the NT
What receptor stimulation causes respiratory secretions to increase? What drug can be used to reduce this?
Cholinergic stimulation (ACh)
Ipratropium bromide can be used to help reduce respiratory secretions.
Drugs that increase intracellular levels of cyclic AMP produce what?…
Bronchodilation
What are 3 bronchodilator drugs?
- sympathomimetics
- xanthine derivatives
- parasympatholytics
What are sympathomimetics?
- drugs that partially or completely MIMIC the action of NA or adrenaline
- act DIRECTLY on alpha &/or BETA adrenoceptor or INDERECTLY on presynpatic terminals, usually by causing a release of NA
E.g. salbutamol (stimulates beta-2 adrenergic receptors)
How does activation of beta-2 adrenergic receptors cause relaxation of smooth muscle?
Activation of beta 2 adrenoceptors increases intracellular cAMP, which activates protein kinase. This inhibits muscle contraction by phosphorylation & inhibiting myosin-light-chain kinase.
What are xanthine derivatives?
Either used in combo with anti inflammatory or if asthma is resistant to other drugs.
:( has lots of side effects e.g. nausea, headache, insomnia & abdo discomfort
E.g. theophylline
- inhibits the enzyme phosphodiesterase, so prevents breakdown of cyclic AMP levels in smooth muscle of airways =relaxation of smooth muscles
- inhibits chemical mediators from being released from mast cells.
- in COPD, it decreases secretions + stimulates resp
- overdose causes cardiac and CnS stimulation and can cause seizures
Also…
- increase adrenaline secretion
- stimulate heart. Cause vasodilation in most blood vessels
What are parasympatholytics?
Drugs that block cholinergic receptors (anticholinergic), musclarinic receptors at bronchioles = bronchodilation and decreases resp secretions
E.g. ipratropium is a musclarinic antagonist
Why shouldn’t asthmatics take paracetamol or ibuprofen?
They can cause bronchoconstriction
How do corticosteroids work?
Act on immune system by blocking production of substances that trigger allergies and inflammatory actions e.g. prostaglandins. Also prevent function of WBCs (this can cause a side effect of increased susceptibility to infection).
The adrenal cortex releases servers steroid hormones into circulation. These are divided into 2 classes….
- mineralocortocoids - mainly aldosterone- have salt retaining activity
- glucocorticoids -mainly cortisol (hydrocortisone) - affects carbohydrate & protein metabolism
Give examples of indirectly acting sympathomimetics.
- amphetamines
- cocaine - inhibits reuptake of NA by nerve terminals
- They displace NA from its storage vesicles, causing its release from nerve endings
- inhibit action of MAO
What role does beta adrenergic drugs have on labour?
They are used to relax uterine muscle to prevent preterm labour.
E.g. ritodrine
What are beta 1 receptors used for?
-found mostly in heart, also located on fat cells, sphincters + smooth muscle of GI tract + renal arterioles
Stimulation leads to…
- used to stimulate the force of heart contraction in low-output heart failure, heart rate, conduction, contraction and ejection fraction of heart
- decreased digestion + intestinal motility
- increased lipolysis in adipose tissue leading to increased blood lipids
- increases release of renin into renal blood (leads to formation of angiotensin II - vascoconstrictor)
- beta 1 receptors have an equal affinity for both adrenaline + NA
- Beta 1-adrenoceptor agonist e.g. dobutamine + NA + dopamine + adrenaline