Adrenergic AgonistsTUTORIAL

Question 1

For each of the following catecholamines give a short a commentary on their cardiovascular effects after I.V. infusion in humans at therapeutic doses:

i. Norepinephrineii. Epinephrineiii. IsoprenalineIn your comment, state:

i. Mechanisms of CVS changes as regards sBP, dBP,HR ,and total peripheral resistance.

ii. Effect of pretreatment with an α-blocker in each case.

Question 2

What are the advantages of the use of Dopamine instead of Norepinephrine in treatment of shock

Question 3 Both α-1 receptor stimulation and β-2 receptor

blockade lower IOP. comment

Question4 Give two examples for:

i. Selective α-1- agonists

ii. Selective α-2- agonists

iii. Selective β-1- agonists

iv. Selective β-2- agonists

For each of the previous classes, mention two therapeutic uses

CASE

Case history

A 6-year- old boy with a history of a mild hay fever, which was treated successfully with OTC medications, had an anaphylactic reaction as a result of a bee sting.

In this emergency ,epinephrine 0.3 mg in sterile water was ordered , to be given S.C.

By error ,however ,it was given I.V. by a young attending nurse in the E.R.. It resulted in dangerously high blood pressure (180/125 mmHg) and heart rate (125 bpm). The boy was clearly distressed, tense , and frightened. He had fine tremor of the hands, cold clammy skin, and appeared to have a respiratory difficulty.

Questions

1. Discuss the significance of use of Epinephrine as a drug of choice in anaphylactic shock.

2. Would Norepinephrine be a suitable choice for the management of anaphylaxis?

3. Suggest suitable corrective measures to control this crisis