QuestionSBA
QuestionChoice
Blocking beta<sub>1</sub>-adrenoceptors would lead to a decrease in cardiac output as it would decrease ionotropism and chronotropism of the heart. However, blocking beta<sub>2</sub>-adrenoceptors would cause increased peripheral resistance and bronchoconstriction, which would be contraindicated in this asthmatic patient.
10000613
c
Combined beta<sub>1</sub> and beta<sub>2</sub> antagonist
QuestionChoice
Beta<sub>1</sub> adrenoceptors cause positive ionotropism and chronotropism of the heart. Therefore, by blocking these receptors, cardiac output is reduced and blood pressure is reduced. Beta<sub>2</sub> adrenoceptors cause vasodilation in the peripheral vessels and lungs, so increasing the effect of these receptors will decrease peripheral resistance and increase bronchodilation. Therefore, this is the best choice, as there will be no bronchoconstriction side-effects, and his blood pressure will be lowered.
10000611
a
Combination beta<sub>1</sub> antagonist and beta<sub>2</sub> agonist
QuestionChoice
Beta<sub>1</sub>-adrenoceptors are located on the heart and cause increased ionotropism and chronotropism, so blocking them would decrease cardiac output, thus reducing his blood pressure, whilst theoretically having no adverse effects on his breathing or peripheral circulation. However, as we can cause bronchodilation via beta<sub>2</sub>agonism, a beta<sub>1</sub> antagonist + beta<sub>2</sub> agonist combination would be the best choice for this patient due to his asthma.
10000614
d
Selective beta<sub>1</sub> antagonist
QuestionChoice
Alpha-adrenoceptors cause vasoconstriction whilst beta<sub>2</sub>-adrenoceptors cause vasodilation of the peripheral vessels and within the lungs. Beta<sub>1</sub>-adrenoceptors cause positive ionotropism and chronotropism within the cardiac muscle. Therefore, blocking Beta<sub>1</sub>-adrenoceptors would decrease cardiac output, and blocking alpha-adrenoceptors would decrease peripheral resistance, leading to a decrease in blood pressure. However, by blocking beta<sub>2</sub>-adrenoceptors bronchoconstriction may occur which would be a contraindication given that this patient has asthma.
10000612
b
Mixed alpha/beta antagonist
QuestionChoice
Alpha-adrenoceptors are not found in the heart, they are found in the periphery and smooth muscle, where they cause vasoconstriction when bound to by noradrenaline. Therefore, blocking them simply causes vasodilation of the periphery and increased blood flow to the skin and gut, with no effect on the heart.
10000615
e
Selective alpha antagonist
Concept
Chapter
2693
3701
Hypertension
Topic
134
Cardiology
12669
A 50-year-old male with asthma is being treated for treatment-resistant hypertension.

Which of the following treatments is most appropriate for managing his hypertension without compromising his airways?
a