Beta 2 agonists

Question 1

What are the generic and brand names of beta 2 agonists?

Answer 1

• Salbutamol (Ventolin, Salamol easybreath) – short acting
• Salmeterol (Serevent) – long acting
• Formoterol (Atimos) – long acting
• Terbutaline (Bricanyl) – short acting

Question 2

What is the method of action of beta 2 agonists?

Answer 2

• Beta2 receptors are found in smooth muscle of the bronchi, GI tract, uterus and blood vessels
• Receptor simulation = smooth muscle relaxation
• = improves air flow
• Beta2 receptors also stimulate Na+/K+-ATPase pumps
• = shifts K+ extracellularly → intracellularly

Question 3

What are the indications for beta 2 agonists?

Answer 3

• Asthma – relieve breathlessness
• COPD – relieve breathlessness
• Hyperkalaemia – nebulised salbutamol used as an additional treatment for urgent high serum K+ concentration)

Question 4

What are the contraindications for beta 2 agonists?

Answer 4

• Cardiovascular disease – tachycardia may cause angina/arrhythmias

Question 5

What are the side effects of beta 2 agonists?

Answer 5

• Tachycardia
• Palpitations
• Anxiety
• Tremor
• ↑ serum glucose levels
• ↑ serum lactate levels – at high doses
• Muscle cramps – long term use

Question 6

What drugs interact with beta 2 agonists?

Answer 6

• Theophylline – may cause hypokalaemia

* Corticosteroids – may cause hypokalaemia

Question 7

Which organ eliminates beta 2 agonists?

Answer 7

Kidneys

Question 8

What information should a patient taking beta 2 agonists be told?

Answer 8

• Must be combined with inhaled corticosteroids in asthmatics – explain importance of compliance
• Explain how to use an inhaler and check technique
• If inhaler is being used frequently then they should seek medical advice