Respiratory Drugs Flashcards
What are SABAs and LABAs
Short acting beta agonists
Long acting beta agonists
What are the main indications of SABA or LABAs?
- Asthma
- COPD
- Hyperkalaemia (nebulised)
Give some examples of SABAs?
Salbutamol and Terbutaline
Give some examples of LABAs?
Salametrol and Formoterol
What is the MOA of the Beta agonists in treating breathlessness?
This drug activates the beta 2 receptors found in the smooth muscle of the bronchi, gut, uterus, blood vessels.
this activation will stimulate the GPCR signalling cascade, this in turn causes smooth muscle relaxation.
This improves airflow in constricted airways to reduce the symptoms of breathlessness.
What is the MOA of beta agonists in the treatment of Hyperkalaemia?
This drug stimulates Na/K ATPase pumps causing K+ to move from outside to inside of the cells.
Useful in treatment of hyperkalaemia, esp when IV access is difficult; should not be used in isolation
What are the side effects of beta agonists?
Common:
- Palpitations
- Tachycardia
- Anxiety
- Tremor
Promote glycogenolysis which increases serum glucose concenctration.
At high doses, serum lactate levels may rise
LABAs can cause muscle cramps
Whom are beta agonists contraindicated in?
LABAs MUST BE GIVEN WITH AN ICS in asthma
CAUTION in patients with cardiovascular disease
- Tachycardia may provoke angina/ arrhythmias
What are the key interactions of beta agonists?
Effectiveness may be reduced by BETA-BLOCKERS
Concomitant use of high-dose nebulised beta2-agonists with THEOPHYLLINE and COTICOSTEROIDS can cause hypokalemia so serum K conc should be monitored
Give examples of ICS and what it stands for:
Inhaled corticosteroids
Clenil
Budesonide
What are the main indications of ICS?
Asthma and COPD
What is the MOA of ICS?
Pass through the plasma membrane to interact with receptors in cytoplasm.
Activated receptor passes into the nucleus to downregulates pro-inflammatory interleukins, cytokines and chemokinesAND upregulates anti-inflammatory proteins.
In the airways ICS reduce the mucosal inflammationto Widens the airwaysAND reduces mucus secretionwhich Improves symptoms and reduces exacerbations in asthma and COPD.
What are the main side effects of ICS?
Locally:
- Oral candidiasis
- Hoarse voice
- increase rick of pneumonia in COPD
Very little is absorbed into blood so few systemic adverse effects - unless taken at very high dose in which can experience:
- Adrenal suppression
- Growth retardation
- Osteoporosis
Whom are ICS contraindicated in?
High-dose ICS, esp fluticasone, used with caution in:
- COPD pts with a history of pneumonia
- Children, where there is potential for growth suppression
What are the main indications of Theophylline?
- Reversible airway obstruction
- Severe acute asthma
- Chronic asthma
- COPD
What is the MOA of Theophylline?
Non-selectively inhibits phosphodiesterase which breaks down cAMP.
Directly stimulates the respiratory centre to increase respiration
Inhibits adenosine A1 and A2 receptors.
What are the main side effects of Theophylline?
- Anxiety
-Arrhythmias - Diarrhoea
- Dizziness
-GI discomfort - GORD
- Headache
- Palpitations
- Seizure
- Skin reactions
- Sleep disorders
- Tremor
- Urinary disorders
Whom is Theophylline contraindicated in?
Cautions:
- CARDIAC ARRHYTHMIAS
- Elderly
- Epilepsy
- Fever
- HTN
- Peptic ulcer
- Risk of HYPOKALAEMIA
- Thyroid disorder
- In adults, prescription potentially inappropriate (STOPP criteria) as monotherapy for COPD (safer and more effective alternatives available; risk of adverse effects due to narrow therapeutic index)
What other drugs/ factors does Theophylline interact with?
SMOKING can increase theophylline clearance
- Increased doses of theophylline are therefore required
- Dose adjustments are likely to be necessary if smoking started or stopped during treatment.
Potentially serious hypokalaemia may result from BETA 2 AGONIST therapy.
- Particular caution is required in severe asthma - this effect may be potentiated by concomitant treatment with theophylline and its derivatives, corticosteroids, and diuretics, and by hypoxia
What kind of drug is Carbocisteine?
Mucolytic
What are the main indications for carbocisteine?
- paracetamol poisoning
- prevention of renal injury especially contract nephropathy (no evidence for this )
- reduce viscosity of respiratory secretions
What are the main side effects of Carbocisteine?
Can cause anaphylactoid reaction – similar to anaphylactic reaction: nausea, tachycardia, rash, wheeze BUT involves histamine release independent of IgE antibodies
When administered in nebulized form as a mucolytic, acetylcysteine may cause bronchospasm
What is the main indications of antihistamines?
- allergies
- hayfever
- allergic rhinitis
- urticaria
- anaphylaxis
Other drugs in this class may be used for nausea and vomiting (antiemetics, histamine H2-receptor antagonists)
Give an example of sedating antihistamine
Chlophenamine
What are the main side effects of antihistamines?
‘First-generation’ anti-histamines e.g. chlorphenamine cause SEDATION
- Because histamine, via H1 receptors, has a role in the brain in maintaining wakefulness
Newer ‘second-generation’ antihistamine do not cross the blood-brain barrier so are non-sedating. Have few adverse effects. Examples include:
- Loratadine
- Cetirizine
- Fexofenadine
what are antihistamines contraindicated in?
Sedating antihistamines should be avoided in severe liver disease
- May precipitate hepatic encephalopathy
What are the main indications for giving Oxygen?
- acute hypoxaemia
- pneumothorax, it accelerates reabsorption of pleural gas
- carbon monoxide (CO) poisoning, reduces carboxyhaemoglobin half-life
- Chronic hypoxaemia – Long Term O2 therapy
What are the main side effects of Oxygen therapy?
Side effects of delivery device:
- Discomfort of a face mask
- Its lack of water vapour causing DRY THROAT (humidification may improve this)
Whom is giving oxygen contraindicated in?
Pts with chronic T2 resp failure e.g those with severe COPD
- As they exhibit several adaptive changes in response to hypoxaemia and hypercapnia, exposure to high inspired O2 conc may disturb the finely balanced adaptive state increased PaCO2
- Resp acidosis
- Depressed consciousness
- Worsened tissue hypoxia
O2 accelerates combustion and therefore presents a fire risk if exposed to a heat source or naked flame, including from smoking
What are oral corticosteroids indicated in?
- allergic or inflammatory disorders
- suppression of autoimmune disease
- cancers to reduce tumour associated swelling
- hormone replacement in Adrenal insufficiency and Hypopituitarism
List some examples or oral corticosteroid?
Prednisolone, hydrocortisone, dexamethasone
What is the MOA of oral corticosteroid?
this drug binds to cytosolic glucocorticoid receptor which translocate to the nucleus and bind to glucocorticoid-response elements which regulates gene expression
How does oral corticosteroids modify the immune response?
Modifies the immune response:
- Upregulate anti-inflammatory genes
- Downregulate pro-inflammatory genes (e.g. cytokines, TNFalpha)
- Suppresses circulating monocytes and eosinophils
What are the metabolic effects of oral corticosteroids?
Metabolic effects include:
- Gluconeogenesis from increased circulating a.a. and fatty acids, released by catabolism of muscle and fat
What are the effects of mineralocorticoids?
Mineralocorticoids effects:
- Stimulates Na+ and water retention and K+ excretion in renal tubule
What are the main side effects of oral corticosteroids?
- immunosuppression
- DM
- Osteoporosis
- insomnia
- confusion
- Adrenal atrophy
- withdrawal can lead to addisonian crisis
What are some side effects Mineralocorticoids?
- Hypertension
- Hypokalemia
- Oedema
Whom are oral corticosteroids contraindicated in?
caution in people with:
- Infection
- children (can suppress growth)
What are the Key interactions of oral corticosteroids.
- Increase the risk of peptic ulceration and GI bleeding when used with NSAIDs
Enhance hypokalaemia in pts taking:
- Beta2 agonist
- Theophylline
- Loop diuretics
- Thiazide diuretics
Efficacy may be reduced by cytochrome P450 inducers (e.g. phenytoin, carbamazepine, rifampicin)
Reduce the immune response to vaccines
Give an example of a leukotriene receptor antagonist
Montelukast
What are the main indications of Leukotriene receptor antagonist.
- Asthma
What is the MOA of Leukotriene receptor antagonist?
In asthma, leukotrienes produced by mast cells and eosinophils (amongst other sources) activate the G protein-coupled leukotriene receptor CysLT1 which activates a cascade of pathways.
This leads to inflammation and bronchoconstriction that contributes to the pathophysiology of asthma
This drug blocks CysLT1 receptor which dampens down the inflammatory cascade leading to reduced inflammation and bronchoconstriction in asthma.
What are the main side effects of Leukotriene receptor antagonist?
Common:
- headaches
- abdominal pain
- increased rate of URTI
Uncommon:
- Hyperactivity
- reduced ability to concentrate
Churg-strauss syndrome ??
What are the key contraindications of Leukotriene receptor antagonist?
- pregnancy (not enough evidence)
