Respiratory Drugs Flashcards
What type of drug is salbutamol?
Beta 2 agonist
How does salbutamol work with regards to breathlessness?
Stimulates beta 2 receptors
These cause smooth muscle relaxation in bronchi, GI tract, uterus and blood vessels
How does salbutamol work with regards to hyperkalaemia?
Beta 2 agonists stimulate sodium/potassium ATPase pumps
This stimulation causes potassium to move from the extracellular compartment to the intracellular compartment lowering potassium levels in the blood
Helpful in treatment for hyperkalamia but shouldn’t be used in isolation
Give examples of other beta 2 agonists
Salbutamol, salmeterol, foametrol, terbutaline
What are the common indications for the use of salbutamol?
- Asthma - short acting relieve breathlessness. Long acting are used as step 3 treatment for chronic asthma BUT MUST BE GIVEN WITH INHALED CORICOSTEROIDS
- COPD - short acting to relieve breathlessness. Long acting are second line for treating COPD
- Hyperkalaemia - nebulised salbutamol along with insulin, glucose and calcium gluconate
What are the contra-indications for salbutamol?
When treating asthma only give long acting beta 2 agonists with CORTICOSTEROIDS - increased asthma deaths
Take care when prescribing beta 2 agonists in someone with CARDIOVASCULAR DISEASE (tachycardia might provoke angina or arrhythmias)
What are the side effects of salbutamol? (4)
- Activation of beta 2 receptors occurs in other tissues causing fight or flight responses!
- tachycardia, palpitations, anxiety, dry mouth and tremor - Beta 2 agonists induce glycogenolysis so may increase glucose levels
- At high doses serum lactate levels rise
- Long acting beta 2 agonists may cause muscle cramps
What interactions with other drugs may salbutamol have?
- beta blockers may reduce the effectiveness of beta 2 agonists
- Use of high dose nebulised beta 2 agonists with theophylline and corticosteroids can lead to hypokalaemia (serum potassium levels need monitored)
How is salbutamol eliminated from the body?
Metabolised in the liver and excreted by the urine
What should you tell a patient when prescribing salbutamol?
- When short acting use as required (acute symptoms, before exercise)
- Long acting take twice daily with steroid (usually combination inhaler e.g. symbicort)
- If using too much consult doctor
When prescribing nebuliser therapy of salbutamol when should it be driven by oxygen and when should it be driven by air?
Oxygen driven in asthma
Medial air in COPD (due to risk of co2 retention)
What type of drug is tiotropium?
Anticholinergic/Antimuscarinic/Bronchodilator
How does tiotropium work?
Antimuscarincs bind to the muscarinic receptor - here the competitively inhibit acetylcholine.
Acetylcholine binding to the muscarinic receptor usually causes parasympathetic rest and digest effects
By blocking the muscarinic receptor tiotropium stop the rest and digest effects causing - increased heart rate and conduction, REDUCED SMOOTH MUSCLE TONE (including respiratory and Gi tract) and REDUCE SECRETIONS FROM GLANDS in respiratory and GI tract
- Cause pupil dilation and prevent accommodation as a result
Give examples of other antimuscarinics
ipatropium tiotropium and glycopyrronium
What are the common uses of tiotropium?
- COPD: short acting antimuscarinincs are used to relieve breathlessness (i.e. brought on by exercise). Long acting antimuscarnics are used to prevent breathlessness and exacerbations.
- Asthma: short acting are used as adjuvent treatment (along with salbutamol) for relief of breathlessness during acute exacerbations. Long acting are added to high dose inhaled corticosteroids and long acting beta 2 agonists at step 4 of chronic asthma treatment
What are the contra-indications of using tiotropium?
Should be used in caution in patients susceptible to acute angle closure glaucoma - they can precipitate a dangerous rise in intra-ocular pressure
Should be used in caution in patients with or at risk of arryhtmias
What are the side effects of tiotropium?
Dry mouth
What other drugs does tiotropium interact with?
None due to low systemic absorption
How Is tiotropium excreted?
Renally excreted
What should you tell a patient when prescribing tiotropium?
Tiotropium is a long acting anti-muscarininc and is prescribed fro regular administration once daily
Discuss side effects e.g. dry mouth
What type of drug is prednisone?
Corticosteroid (glucocorticoid)
Give other examples of corticosteroids
Prednisolone, hydrocortisone and dexamethasone
How does prednisolone work?
Binds to glucocorticoid receptors
This causes up regulation of anti-inflammatory genes and down regulates pro-inflammatory genes (cytokines and TNF alpha)
Suppress monocytes and eosinophils
Increase gluconeogenesis
Also have mineralocorticoid effect stimulating sodium and water retention and potassium excretion
What are the common indications for the use of Prednisolone?
- Allergic Asthma/Anaphylaxis
- IBD/ Inflammatory arthritis - surpasses autoimmune disease
- Cancers as part of chemotherapy or reduction of tumour associated swelling
- Hormone replacement in adrenal insufficiency or hypopituitarism
What are the contra-indications of the use of prednisolone?
Should be prescribed with caution in people with
- infection
- children (can suppress growth)
What are the acute side effects of prednisolone?
- Immunosuppression increases risk and severity of infection
- Metabolic effects e.g. diabetes, osteoporosis, muscle weakness, skin thinning, easy bruising and gastritis
- Mood and behaviour changes e.g. insomnia, confusion, psychosis and suicidal ideas
- Hypertension, hypokalaemia and oedema
What are the chronic side effects of prednisolone use?
Prednisolone suppresses ACTH hormone production in the pituitary switching off adrenal cortisol production - this can cause ADRENAL ATROPHY
If withdrawn suddenly an acute ADDISONIAN CRISIS with C|B collapse may occur
Slow withdrawal is required
What other drugs does predisolone interact with?
- NSAIDS: Can increase risk of ulceration and GI bleeds
- B2 AGONISTS: can enhance hypokalaemia
- DIURETICS: theophylline, loop or thiazide diuretics can enhance hypokalaemia
- CYTOCROME P450 INDUCERS: phenytoin, carbamazepine, rifamipicine may reduce prednisolone efficacy
- VACCINES: corticosteroids may reduce the immune response to vaccines
What information do you give to patients on prednisolone?
Once daily treatment taken in the morning helps mimic the natural circadian rhythm and reduce insomnia
Do not stop treatment suddenly
Give some examples of inhaled corticosteroids and their uses?
Beclometasone (brown inhaler), budesonide
Preventer inhaler
Used in;
1. Asthma - added where beta 2 agonist along is not controlling asthma well
2. COPD- usually prescribed in combination with a long acting beta 2 agonist or a long acting anti-muscarinic bronchodilator
Adverse effects of inhaled corticosteroids
Oral candidiasis
Hoarse voice
May increase the risk of pneumonia in those with COPD
Less systemic side effects
