Pharmacology

Question 1

Adrenaline

Answer 1

Alpha & Beta adrenergic stimulant.
Beta effects:
- Increases HR by increasing SA node rate
- Increases conduction velocity through AV node
- Increases myocardial contractility
- Increases ventricle irritability
- Bronchodilatation
Alpha:
- Peripheral vasoconstriction
Metabolisim:
- By monoamine oxidase and other enzymes in the blood, liver and nerve endings, excreted by kidneys

Question 2

Aspirin

Answer 2

Analgesic, antipyretic, anti inflammatory and anti-platelet aggregation agent.
- Minimises platelet aggregation and thrombus formation
- Inhibits synthesis of prostaglandins - anti-inflammatory
Metabolism:
- Converted to salicylate in the gut and liver, excreted by kidneys.

Question 3

Ceftriaxone

Answer 3

Cephalosporin antibiotic
Metabolism:
- Excreted unchanged in urine and in bile

Question 4

Dexamethasone

Answer 4

Corticosteroid secreted by adrenal cortex
- Relieves inflammatory reactions
- Provides immunosuppression
Metabolised
- by the liver and other tissues, excreted by kidneys

Question 5

Dextrose

Answer 5

Hypertonic crystalloid solution, made from sugar and water
- provides a source of energy
- supplies body water
Metabolism:
- Dextrose - broken down in most tissues
- stored in liver and muscle as glycogen
Water - excreted by kidneys and distributed throughout body

Question 6

Fentanyl

Answer 6

A synthetic opioid analgesic 
Actions:
CNS:
- Depression - leading to analgesia
- Respiratory depression  - leads to apnoea
- Dependance 
CVS:
- Decreases conduction velocity through the AV node

Metabolised by liver, excreted by kidneys

Presentation: 100mcg in 2ml, 250mcg in 1ml (IN)

Question 7

Glucagon

Answer 7

A hormone normally secreted by the pancreas
Actions:
Causes an increase in blood glucose concentration by converting stored liver glycogen to glucose.

Presentation: 1mg (IU) in 1ml hypokit

Special note: not all pts will respond to glucagon eg pts with inadequate glycogen stores in the liver (alcoholics, malnourished)

Question 8

GTN

Answer 8

A vascular smooth muscle relaxant
Actions:
- Venous dilatation promotes venous pooling and reduces venous return to the heart (reduces preload)
- Arterial dilatation reduces systemic vascular resistance and arterial pressure (reduces after-load)

Effects:

• Reduced myocardial o2 demand
• Reduced systolic, diastolic and mean arterial BP, whilst usually maintaining coronary perfusion pressure
• Mild collateral coronary artery dilatation may improve blood supply to ischaemic areas of myocardium
• Mild tachycardia secondary to fall in BP
• Preterm labour: uterine quiescence in pregnancy

Metabolised by liver

Presentation: 0.3mg tablet, 50mg transdermal patch (0.4mg/hour)

Special notes:

• Cialis may be prescribed for treatment of BPH
• IV infusion at doctors request must be written up and signed by sending doctor. Uusually ran at 5 to 200mcg/min and increased 3-5mcg/min

Question 9

Heparin

Answer 9

Anticoagulant
Inactivates clotting factors IIa (thrombin) and Xa by binding to antithrombin III

Metabolised by liver, excreted by kidneys

Presentation: 5000 units in 5ml
Special note: do not inject IM due to haematoma risk

Question 10

Ipratropium Bromide

Answer 10

Anticholinergic bronchodilator
Actions:
- Allows bronchodilitation by inhibiting cholinergic broncho motor tone (blocks vagal reflexes which mediate bronchoconstriction)

Excreted by kidneys

Presentation: 250mcg in 1ml

Special notes: Neb mask must be fitted properly to avoid eye contact, and must be administered in conjunction with salbutamol.

Question 11

Ketamine

Answer 11

Anaesthetic agent with analgesic properties at lower doses.
Exact mechanism of action unclear, primarily works as an antagonist at NMDA receptors. May also interact with opioid muscarinic and other receptors.
Produces a trance-like disassociate state with amnesia, with preservation of laryngeal and pharyngeal reflexes

Presentation: 200mg in 2ml

Special note: emergence reactions can be managed with midaz

Question 12

Lignocaine

Answer 12

Sodium channel blocker - interrupts impulse conduction in peripheral nerves and stabilises excitable cell membranes

Presentation: 50mg in 5ml (1% solution)

Question 13

Methoxyflurane

Answer 13

Inhalation analgesic agent at low concentrations

Excreted mostly by the lungs, and by the liver

Presentation: 3ml amp via Penthrox inhaler

Question 14

Midazolam

Answer 14

Short acting CNS depressant
Actions:
- Anxiolytic 
- Sedative
- Anti convulsant 

Metabolised in the liver, excreted by the kidneys

Presentation: 5mg in 1ml, 15mg in 3ml

Question 15

Morphine

Answer 15

An opioid analgesic
Actions: 
CNS effects-
- Depression (leading to analgesia)
- Respiratory depression
- Depression of cough reflex 
- Stimulation (mood changes, vomiting, pin point pupils) 
- Dependence 

CVS effects:

• Vasodilitation
• Decreases conduction velocity through the AV node

Metabolised by liver, excreted by kidneys

Presentation: 10mg in 1ml

Special notes: occasional wheals can be seen in the vein when given IV, which is a normal histamine response

Question 16

Naloxone

Answer 16

An opioid antagonist
Actions:
Prevents or reverses the effects of opioids

Metabolised by the liver

Presentation: 0.4mg in 1ml

Special notes:

• Duration of action is often less than that of the opioid, therefore a repeat dose may be required.
• Should not be administered after a head injury.
• Should not be administered in an opioid overdose arrest - maintain ventilations.
• Naloxone has no perceivable effects in the absence of opioids