Beta2 agonists Flashcards
Give 3 common clinical indications for the use of beta 2 agonists.
1) Asthma
2) COPD
3) Hyperkalaemia
How are beta 2 agonists used in asthma?
SABAs are used to relieve breathlessness.
LABAs are used as step 3 treatment for chronic asthma, but always in combination with an ICS.
How are beta 2 agonists used in COPD?
SABAs are used to relieve breathlessness.
LABAs are used as an option for 2nd line treatment of COPD.
1) How are beta 2 agonists used in treatment of hyperkalaemia?
2) Name 3 other drugs that are used as urgent treatments for hyperkalaemia.
1) Nebulised salbutamol.
2) Insulin, glucose, calcium gluconate.
1) Give the 4 locations that Beta 2 receptors are found.
2) Describe the mechanism of action which helps to relieve breathlessness.
1) Smooth muscle of bronchi, GIT, uterus and blood vessels.
2) Bind to B2 receptors > Stimulates G-protein coupled receptor > signalling cascade leads to smooth muscle relaxation > improves airflow in constricted airways.
1) Describe the mechanism of action of B2 agonists which aids in the treatment of hyperkalaemia.
2) Why should beta 2 agonists not be used in isolation for the treatment of hyperkalaemia?
1) Stimulate Na+/K+ ATPase > shifts K+ from extracellular to intracellular compartment.
2) Because their effect is less reliable than other therapies.
1) Name 2 short acting beta agonists.
2) Name 2 long acting beta agonists.
1) Salbutamol and terbutaline.
2) Salmeterol and Formoterol.
1) Name 4 ‘fight or flight’ adverse effects of beta 2 agonists.
2) Why might beta 2 agonists cause serum glucose levels to rise?
3) What might beta 2 agonists cause at high doses?
4) Name another unmentioned side effect of beta 2 agonists.
1) Tachycardia, palpitations, anxiety and tremor.
2) Because they promote glycogenolysis.
3) Increased serum lactate levels.
4) Muscle cramps.
1) Why should LABAs only be used in asthmatics if they are part of ICS therapy?
2) Why should care be taken when prescribing beta2 agonists for patients with CV disease?
2a) When is this especially important?
1) Because without a steroid, LABAs are associated with an increase in asthma deaths.
2) Because the side effect of tachycardia may provoke angina or arrhythmias.
3) In the treatment of hyperkalaemia, when high doses may be required.
1) What class of drugs might reduce the effectiveness of beta2 agonists?
2) Concomitant use of which drugs can lead to hypokalaemia?
1) Beta blockers.
2) Beta 2 agonists, theophylline and corticosteroids (therefore, monitor serum potassium levels).
1) What is the common choice for the prescription of salbutamol?
2) How is salbutamol prescribed in asthma and COPD patients requiring hospital intervention?
3) How are long acting beta 2 agonists normally prescribed?
1) Salbutamol 100-200mcg inhaler PRN.
2) Salbutamol 2.5mg nebulised 4 hourly.
3) As a combination inhaler with an ICS taken daily.
What should nebulisers be driven by in asthma and COPD patients?
In general, use oxygen in asthma and medical air in COPD.
