Emergency drugs

Question 1

Definition of simple hypotension

Answer 1

A systolic BP below 85 mmhg

Question 2

Describe the following for ephidrine:
1.Drug type
2. Presentation
3. Dose
4. Mode of action
5. effects
6. Use

Answer 2

1. Indirectly acting sympathomimetic
2. 1 ml glass vial containing 30 mg of ephidrine. Usually diluted to 10 ml in normal saline to give a concentration of 3 mg/ml.
3. Bolus 3-6 mg (1-2ml) titrated to effect.
4. Causes release of noradrenaline at sympathetic nerve terminals non-specifically stimulating adrenoceptors. Weak direct action on adrenoceptors. Tachyphylaxis starts to occur at 30mg dose as noradrenaline stores exhausted.
5. alpha and beta adrenoceptor activation causes increased SVR and increased HR
6. Modest hypotension with a normal or slow HR.

Question 3

Describe the following for Phenylephrine
1.Drug type
2. Presentation
3. Dose
4. Mode of action
5. effects
6. Use

Answer 3

1. Synthetic, direct acting sympathomimetic amine
2. 50 -100 micorgram dose titrated to effect
3. Acts directly at the alpha adrenoceptors. NO action at beta.
4. Alpha-adrenoceptor activation causes vasoconstriction and increase in SVR. Reflex bradycardia. May cause a fall in cardiac output if a large dose is given.
5. Severe hypotension associated with a normal/fast HR.

Question 4

Describe the following for Metaraminol:
1.Drug type
2. Presentation
3. Dose
4. Mode of action
5. effects
6. Use

Answer 4

1. Synthetic direct and indirect acting sympathomimetic amine
2. 1ml glass vial containing 10mg. Diluted to 20ml in normal saline to give a dose of 0.5 mg/ml.
3. 0.5 mg bolus titrated to effect.
4. Minimal beta adrenoceptor effects. Acts mainly of alpha1 adrenoceptors causing a rise in SVR and BP. Has no effect on cardiac contractility.
   5.Severe hypotension associated with a normal/fast HR.

Question 5

Describe the following for Atropine:
1. Drug type
2. Presentation
3. Dose
4. Mechanism of action

Answer 5

1. Anticholinergic
2. Usually in 600 microgram/ ml glass ampoules or pre packaged 3 mg/ 10 mls ALS syringes.
3. 500 micrograms to a max of 1200 micrograms (titrated to effect)
4. Blocks effect of Ach at the heart resulting in tachycardia. May act directly at teh vagal nucleus or reflect partial agonist effect at cardiac muscarinic receptors.

Question 6

Describe the following for Glycopyrrolate:
1. Drug type
2. Presentation
3. Dose
4. Mechanism of action

Answer 6

1. Anticholinergic
2. Normally comes in 200 or 600 microgram glass vials. Colourless solution.
3. 100-200 microgram boluses titrated to effect.
4. Blocks the effects of acetylcholine at the heart resulting in a tachycardia.

Question 7

What is the mechanism and dose of salbutamol for bronchospasm?

Answer 7

Beta 2 agonist with some beta 1 agonism at high doses.

Presents as 1 ml ampoule containing 500 micrograms or 5mg in 5ml. Dilute to 50 micrograms/ml.
Give 250 micrograms by slow IV injection (20 mins or 12.5 mcg/min)

Question 8

What is the mechanism and dose of aminophylline for bronchospasm?

Answer 8

Theophylline based preparation. Acts as a non specific phosphodiesterase inhibitor. Increases cAMP in cells leading to smooth muscle relaxation.

250 mg titrated to effect over 20 minutes.

Do not give if patient normally takes theophylline as plasma levels may enter the toxic range.

Question 9

What is the dose of adrenaline in acute bronchospasm?

Answer 9

50 micrograms (o.5 ml) of 1 in 10’000 adrenaline (100 micrograms/ml)

Question 10

What is the initial management of anaphylaxis intraop?

Answer 10

1. Stop administration of culprit drug
2. Call for help
3. Maintain Airway. 100% oxygen and lie patient flat with legs in the elevated.
4. Give adrenaline: IM 0.5 - 1mg very 10 mins as required. IV 50-100 mcg (0.5-1ml 1 in 10’000) titrated to effect.

Question 11

What is the secondary management of anaphylaxis?

Answer 11

1. IV fluids
2. Chlorphenamine (antihistamine) 10 mg IV
3. Hydrocortisone 100 mg IV