GTN

Question 1

Presentation of GTN

Answer 1

0.6mg tablets

Transdermal GTN Patch (0.4mg/hr)

Question 2

Pharmacology of GTN

Answer 2

Principally, a vascular smooth muscle relaxant

Question 3

Pharmacology of GTN (actions)

Answer 3

-Venous dilatation promotes venous pooling and reduces venous return to the heart (reduces preload)

Arterial dilatation reduces systemic vascular resistance and arterial pressure (reduces afterload)

The effects of the above are:

• reduced myocardial oxygen demand
• reduced systolic, diastolic and mean arterial pressure, whilst usually maintaining coronary perfusion pressure
• Mild collateral coronary arterial dilatation may improve blood supply to ischemic areas of myocardium
• Mild tachycardia secondary to slight fall in blood pressure
• Preterm Labour: Uterine Quiescence in pregnancy

Question 4

Metabolism of GTN

Answer 4

By the liver

Question 5

GTN Indications

Answer 5

• Chest pain associated with ACS
• Hypertension associated with ACS
• Acute LVF
• Preterm Labour (consult)
• Autonomic Dysreflexia

Question 6

GTN Contraindications

Answer 6

• Known hypersensitivity
• Systolic BP 150bpm
• Bradycardia HR <160mmHg
• Right ventricular infarct

Question 7

GTN Precautions

Answer 7

• Recent AMI
• Elderly Pt’s
• Concurrent use with other tocolytics
• No previous administraton

Question 8

Route of Administration of GTN

Answer 8

Buccal
Sub-lingual
Transdermal
IV infusion (IHT only)

Question 9

Side Effects of GTN

Answer 9

• Tachycardia
• Hypotension
• Headache
• Skin flushing (uncommon)
• Bradycardia (occasionally)

Question 10

Effects of GTN

Answer 10

Buccal
Onset: 30sec-2min
Peak: 5-10min
Duration: 15-30min

IV
Onset: 30sec-1min
Peak: 3-5min
Duration: 15-30min

Transdermal
Onset: up to 30min
Peak: 2hr