Beta-2 Adrenoceptor Agonists

Question 1

Give 2 examples of short-acting beta-2 adrenoceptor agonists

Answer 1

• Salbutamol

- Terbutaline

Question 2

Give 2 examples of long-acting beta-2 adrenoceptor agonists

Answer 2

• Formoterol

- Salmeterol

Question 3

What is the mechanism of action of beta-2 adrenoceptor agonists?

Answer 3

They bind to beta-2 adenoceptors in bronchial smooth muscle, which activates cAMP, allowing relaxation of the bronchial smooth muscle and dilatation of the airways

Question 4

How can beta-2 adenoceptor agonists be administered?

Answer 4

• Inhaled
• Nebulised
• PO
• IM
• SC
• IV
• Via ET tube

Question 5

What are the indications for the use of beta-2 adenoagonists?

Answer 5

• Asthma and COPD

- Hyperkalaemia

Question 6

Why might beta-2 adrenoagonists be used in hyperkalaemia?

Answer 6

It helps to shift potassium from the extracellular space to the intracellular space, thus reducing serum potassium levels

Question 7

What beta-2 adrenoagonist is used in hyperkalaemia?

Answer 7

Salbutamol (unlicensed)

Question 8

What additional use of beta-2 adrenoagonists may be initiated and supervised by specialists?

Answer 8

Delaying uncomplicated premature labour

Question 9

What are the contraindications to beta-2 adrenoagonists?

Answer 9

Severe pre-eclampsia

Question 10

In what conditions should beta-2 adrenoagonists be used with caution in?

Answer 10

• Arrhythmias
• Cardiovascular disease
• Hypertension
• Susceptibility to QT prolongation
• Diabetes
• Hyperthyroidism
• Hypokalaemia

Question 11

What monitoring is required with beta-2 adrenoagonists?

Answer 11

Review patients asthma/COPD as per local guidelines

Question 12

What other drugs may interact with beta-2 adrenoagonists?

Answer 12

• Methyldopa
• Loop and thiazide diuretics
• Theophylline
• Steroids

Question 13

What may happen when methyldopa is given with beta-2 adrenoagonist?

Answer 13

Acute hypotension (if given with salbutamol infusion)

Question 14

What may happen if beta-2 adrenoagonists are given with loop/thiazide diuretics, theophylline, and steroids?

Answer 14

Increased risk of hypokalaemia

Question 15

What are the common side effects of beta-2 adrenoagonists?

Answer 15

• Fine tremor
• Tachycardia
• Palpitations
• Anxiety

Question 16

What are the less common side effects of beta-2 adrenoagonists?

Answer 16

• Hypokalaemia
• Pulmonary oedema
• Arrhythmias and myocardial ischaemia

Question 17

What counselling is required with beta-2 adrenoagonists?

Answer 17

• Inhaler technique
• Written asthma action plan
• Reason for use
• Tremor and palpitations

Question 18

What counselling is required regarding inhaler technique for beta-2 adrenoagonists?

Answer 18

Educate patient on appropriate inhaler technique and review inhaler technique at follow up

Question 19

What should be done if a patient is struggling with their inhaler technique?

Answer 19

Consider prescribing a spacer device or breath-actuated inhaler

Question 20

What is a written asthma action plan?

Answer 20

Every asthmatic patient must receive a written asthma action plan, which describes the appropriate course of action if their asthma symptoms worsen, or they become severely short of breath

Question 21

What should be clarified regarding the reason for use of beta-2 adrenoagonists?

Answer 21

Should clarify that the inhaler containing the SABA, e.g. salbutamol, is the reliever, and the LABA should not be used during asthma attacks, and the prescribed dose should not be exceeded