Respiratory Drugs and Pharmacology Flashcards
What are 3 common Bronchodilator drugs?
Beta2 agonists (salbutamol/terbutaline)
Anticholinergic agents (ipatropium/glycopyrronium/tiotropoum)
Methylxanthines
(theophylline)
What are 4 common Anti Inflammatory agents?
Corticosteroids (fluticasone)
Disodium Cromoglycate
Sodium Nedocromil
Leukotriene Receptor Antagionists (LRTA) (e.g. Montelukast)
Give 2 antimicrobial agents?
Anti-bacterial drugs (antibiotics)
Anti fungal drugs (Rx od aspergillosis)
What agents can be used for humidification or secretion clearance?
Water and Saline.
Give 3 routes of delivery for Respiratory drugs/BD’s?
- Inhaled
- Oral
- IV
What does CSIT mean?
Continuous Subcutaneous Infusion of Terbutaline (CSIT)
What does CSIT do?
Improves Asthma Control
What can CSIT decrease?
- Less hospitalisation
- Less Corticosteroid Need
Who benefits most from CSIT?
Wide diurnal variability in PEF aka Brittle Asthmatics
Advantages of the Inhaled Route?
- Deliver directly to the large surface area of trachea-bronchial tree
- Therapeutic levels of drugs can be achieved locally with the bronchi leading to a more rapid onset of action
- Requires a lower dose of drug via oral route
- Lower incidence of side effects since systemic concentrations are lower
How do Bronchodilators work?
–> Bronchial smooth muscle contains both alpha and beta adrenergic receptors
–> If Beta receptors stimulated, mimic the activity of the sympathetic nervous system (-> dilation)
–> Beta 2 Agonists (Agonist - substance which initiates a physiological response when combined with a receptor)
Alpha adrenergic receptors causes
Smooth muscle contraction
Beta adrenergic receptors -
Smooth muscle relaxation
Where are Beta Receptors present?
In a high concentrations in lung tissue.
70% of Beta Receptors found in:
- Airway smooth muscle
- Epithelium
- Vascular Smooth Muscle
- Submucosal glands
Describe the density of Beta 2 receptors?
- The density in airway smooth muscle does not change at different airway levels
- Bronchioles have a similar density to large airways
- Beta agonists may bronchodilator all airways
Where are beta receptors localised to?
Submucosal Glands
- May lead to increase in mucus clearance
- Increase Ciliary Beat Frequency
What is the mode of action for beta 2 receptors?
1 -> Inhaled drugs stimulates Beta2 receptors in bronchial smooth muscle of obstructed airway
2-> Leads to activation of the enzyme adenyl cyclase
3-> Leads to increased production and elevation of cellular cyclic AMP in airway smooth muscle and mast cells
4-> AMP causes relaxation of smooth muscle by decreased Ca
5-> Increased cAMP inhibits release of bronchoconstrictor mediators from mast cells such as histamine and leukotrienes
6-> Leads to bronchodilation
What is the onset for SABA’s?
1-2 minutes
When is maximal effect of a SABA?
20 mins after having it
How long does bronchodilation last?
3-6 hours
How long do Long acting stimulants last?
12 hours such as Salmeterol
Indications such as OLC?
Asthma
COPD
List Side Effects (4)
1 - Skeletal muscle tremor
2- Tachycardia
3-Metabolic changes (Hypokalaemia and HyperGlycaemia)
4-Cardiac Arrythmia
Contraindications?
- Hypersensitivity to drug
- Pregnancy/Breast feeding
- Tachyarrhythmia
- Children aged 2 or below
- Signed referral from HCP
Why do we use Beta Blockers?
Manage CVD
Non Cardiovascular management of migraine/anxiety
How do BB work?
They oppose action of B2 agonists and so care must be taken when prescribing
What can BB cause in terms of fev1?
Decrease FEV1 and increased symptoms in asthmatics
What are the 2 types of BB?
Non Selective and Cardio Selective
Action of Non Selective BB?
Block B1 and B2 receptors
Action of Cardio Selective BB
Block B1 and can block B2 in high doses
Example of Non Selective BB
Propranolol
Example of Cardio Selective BB
Atenolol
What is an anticholinergic agent?
Opposes the effects of the parasympathetic nervous stimulation of bronchial smooth muscle
How do anticholinergics work?
1 - Block Vagal reflex
2- Block the binding site for ACh for cholinergic receptors
3- Prevent increase in cGMP
Leads to bronchodilation
How do anticholinergic agents interact with muscarinic receptors?
They antagonise muscarinic receptors in the airways
How do these agents work?
- Blocking cholinergic component of bronchoconstrction
- major targets for AntiCh drugs are muscarinic receptors
What innervates respect tract?
Vagus nerve
What does vagus nerve innervate?
airway smooth muscle and submucosal glands
Where is vagus innervation found?
Predominantly larger airways and higher density of muscarinic receptors In large airways
Which muscarinic receptors mediate bronchoconstriciton in human airways?
M3
Examples of Anticholinergic Agents?
Ipatropium Bromide
Tiotropium Bromide (Spiriva)
Slower or Faster than B2?
Slower takes 15-30mins
Peak observed between 1-2 hours
How can they be used to maximise bronchodilation?
Combine with B2 agonists
How many hours (Spiriva)
18-24
Side effects? of AntiCHO
- Dry Mouth
- Headache
- Skin flushing
- Tachy
- Caution for glaucoma
- Care in pregnancy
What are Anti Inflammatory Agents?
‘Preventer’
(Corticosteroids)
- Seen as most effective treatment for asthma
Example of Anti Inf A?
Flixotide/Becotide
How do anti inflam ag work?
Not fully understood.
-Gene transcription,transgresson
-Cotricosteroids decrease number of inflammatory cells
(Eosinophils/Mast cells)
-They increase production of anti inflammatory proteins eg Interleukin-10
What is the nuclear model?
1) Steroid diffuses into cell and binds to specific receptor forming complex
2) Complex enters nucleus and influences mRNA synthesis from DNA (RNA polymerase) and makes protein
3) Cells and mediators that make inflammatory response are modified to inhibit process
Side effects of anti inflammatory agents?
- Dysphonia (hoarse voice)
-Sore throat
-Thrush (oral candidacies)
-Adrenal suppression
-decreased bone density
-weight gain
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