Pharmacology Action

Question 1

ADRENALINE – action

Answer 1

Stimulates the ALPHA and BETA subdivisions of the sympathetic nervous system to produce the “Fight” or “Flight” reaction

• ALPHA stimulation causes peripheral vasoconstriction. It raises the perfusion pressure of vital organs during cardiac arrest and it decreases capillary permeability and increases blood pressure in anaphylaxis
• BETA 1 stimulation causes increased myocardial excitability, tachycardia, and increased myocardial contractility
• BETA 2 stimulation causes bronchodilation

          **Onset**                    **Peak**              **Duration**

IM 30-90sec 4-10min 5-10min

IV 30sec 3-5min 5-10min

NEB 1-5min n/a up to 20min

Question 2

AMIODARONE – actions

Answer 2

• Slows the sinus rate and increases the refractory period of the AV node.
• Decreases peripheral vascular resistance

IV

onset- 2 mi

Peak- 20 min

Duration - 120 min

Question 3

ASPIRIN - Actions

Answer 3

• Inhibits platelet aggregation thereby limiting thrombus enlargement in acute coronary syndrome
• Reduces production of prostaglandins thereby relieving pain and fever

Onset 2-10 min

Duration 3-6 hours

Question 4

ATROPINE - Action

Answer 4

Antagonises the parasympathetic effects of acetylcholine on muscarinic receptors resulting in:

• Increased heart rate via increasing intrinsic rate of the sino-atrial node andconduction through the atrio-ventricular node
• Reducing smooth muscle contraction resulting in pupillary dilation, reducedgastrointestinal motility and reduced bladder tone
• Blocks exocrine gland activity causing decreased salivary, bronchial, gastric andsweat secretions

             **Onset**           **Peak**                 ** Duration**

IM Depends on perfusion

IV <2min <5 min 2-6hours

Question 5

CALCIUM GLUCONATE – action

Answer 5

Antagonises the effect of hyperkalaemia on the heart

IV

Onset - 30 sec

Peak- N/A

Duration - 30min - 2hrs

Question 6

FENTANYL - Action

Answer 6

• Potent analgesic
• Effective drug for intranasal use because it is rapidly absorbed across mucous membranes

Onset 2-3 min

Duration 30-60 min

Question 7

FEXOFENADINE - Action

Answer 7

Non‐sedating anti‐histamine

Onset 15-30min

Duration 12-16 hours

Question 8

FRUSEMIDE - Action

Answer 8

A potent loop diuretic which produces increased urine output

IV

Onset - 5 min

Peak - 20 -60 min

Duration - 2-3 hours

IM

Onset - 10 min

Peak - 30 min

Duration - 2-3 hrs

Question 9

GLUCAGON - Action

Answer 9

Converts liver glycogen to glucose. Glucagon may not work if liver glycogen is depleted due to starvation or chronic liver disease

Question 10

GLUCOSE 10% - Action

Answer 10

Principle energy source for body cells, especially the brain.

IV

Onset - 30sec

Peak - 30sec

Duration - Dependant on severity of hypoglycaemic episode

Question 11

GLUCOSE GEL - Action

Answer 11

Principle energy source for body cells, especially the brain

PO: Onset within 15 minutes

Question 12

GLYCERYLTRINITRATE - Action

Answer 12

• Dilates coronary arteries
• Dilates systemic veins and arteries
• Decreases preload, afterload and blood pressure

Onset is within 2 minutes and lasts up to 30 minutes

Question 13

HARTMANN’S - Action

Answer 13

Following intravenous infusion it is distributed throughout the extracellular fluidspace. Approximately 25% of the volume infused stays in the intravascular space for a variable period of time.

Question 14

IPRATROPIUM BROMIDE - Action

Answer 14

• Bronchodilation
• Blocks vagal reflexes which mediate bronchoconstriction
• Synergistic when used in combination with salbutamol

Onset 3-5min

Duration 2-4hr

Question 15

LIGNOCAINE - ACTION

Answer 15

Blocks sodium channels reducing ventricular excitability and pain transmission

IV

Onset 1-4min

Peak 5-10 min

Duration 20 min

Question 16

METHOXYFLURANE - Action

Answer 16

Central nervous system depressant

• Onset 2-3min
• Duration 30min

Question 17

METOCLOPRAMIDE - Action

Answer 17

Blocks central dopamine receptors

IM

ONSET – 10 to 15 minutes

DURATION – 1 to 2 hours

IV

ONSET – 3 to 5 minutes

DURATION – 1 to 2 hours

Question 18

MIDAZOLAM - Action

Answer 18

Reduces seizure activity and has a tranquillising and amnesic effect

** Onset, Peak, Duration**

IM 5‐10 min, 15 min, 30 min

IV 1‐3 min, 10 min, 20 min

I**N ** 1‐3 min, 12 min, 20 min

Question 19

MORPHINE - Action

Answer 19

• Decreases pain perception and anxiety
• Causes peripheral vasodilation

IM

Onset 5-10 min

Peak 25-40 min

Duration 1-2 hrs

IV

Onset 2-5 min

Peak 10 min

Duration 1-2 hrs

Question 20

NALOXONE - Action

Answer 20

Reverses symptoms caused by opioid analgesics:

• Respiratory depression
• Sedation
• Hypotension

   Onset            Peak               Duration

IM 2-5 min 10-15 min 20 min approx

IV 1-3 min 10-15min 15 min approx

Question 21

ONDANSETRON - Action

Answer 21

Blocks central and peripheral 5-HT3 receptors

IM

Onset 10-15 min

Duration 1-2 hrs

IV

Onset 3-5min

Duration 1-2 hrs

Question 22

SALBUTAMOL - Action

Answer 22

Stimulates beta 2 receptors in bronchial smooth muscle resulting in bronchodilation

NEB

Onset - 2-5 min

Peak - 5 -10 min

Duration - 1-2 hours

Question 23

SODIUM BICARBONATE – actions

Answer 23

• Reverses metabolic acidosis by buffering hydrogen ions
• Reduces plasma potassium by altering pH and causing intracellular movements of potassium ions
• Alters protein binding of tricyclics by acting on trans‐membrane sodium channels

Question 24

KETAMINE - Action

Answer 24

Action

• Dissociates the central nervous system from painful stimuli. At low doses ketamine causes a trance like state characterised by analgesia and amnesia with retention of protective airway reflexes, spontaneous respirations and cardiovascular activity.

Question 25

Sodium Chloride 0.9% - Action

Answer 25

Following intravenous infusion it is distributed throughout the extracellular fluid space. Approximately 25% of the volume infused stays in the intravascular space