GTN

Question 1

What is The Pharmacology of GTN

Answer 1

GTN is Principally a smooth muscle relaxant that causes.

• Venous Dilation, promotes venous pooling and reduces venous return to the heart (Preload).
• Atrial Dilation reduces systemic vascular resistance (SVR) and atrial pressure (After-load).

The effects above cause

- Reduce Myocardial O2 Demand.
- Reduce systolic, diastolic and mean arterial blood            pressure whilst usually maintaining coronary perfusion  pressure. 
- Mild collateral coronary arterial dilation may improve blood supply to ischemic parts of the myocardium. 
- Mild tachycardia secondary to slight BP drop. 
- Preterm Labour; Uterine Quiescence in pregnancy

Question 2

What is the presentation of GTN and how is it Metabolize

Answer 2

300mcg tablet.
600mcg tablet.
Transdermal Patch (50mg 0.4mg release per hour)

Metabolized
By the Liver.

Question 3

What are the Indications and Contraindications of GTN

Answer 3

Indication

• Acute Coronary Syndrome
• Autonomic Dysreflexia
• Acute Left ventricular Failure (APO)
• Hypertension associated with ACS.
• Preterm Labour (Consult)

Contraindications ( 2 Drugs/ 3 BP’s / 4 Hearts)

• Hypersensitivity
• Sildenafil or Levitria in the last 24 hours or Cialis in the last 4 days.
• HR < 50 Excluding Autonomic Dysreflexia
• HR > 150
• VT
• Right MI
• BP < 90 For Patch
• BP < 110 for Tablet
• BP < 160 systolic with patients having a inferior STEMI.

Question 4

What are the Side Effects and Precautions of GTN

Answer 4

Side Effects

• Hypotension
• Tachycardia
• Bradycardia
• Skin flushing
• Headache

Precaution

• Elderly and Frail
• No previous Admission
• Recent MI
• Concurrent use of other Tocolystics

Question 5

Route of Administration and Special Notes.

Answer 5

Route of Administration

• Sub Lingual
• Buccal
• Transdermal

Special Notes

• Do not Administer Pt’s own medication as it may not have been stored appropriately
• Both Men and Women can Take PDE5 Inhibitors (Viagra) so they should both be asked Contras.
• GTN infusion may be required for Inter hospital Transfer via Doctors orders.
• Cialis may be prescribed to Men for benign prostatic hypertrophy.

S/L Effects

• Onset: 30 secs - 2 Minutes
• Peak: 5 - 10 Minutes
• Duration: 15 - 30 Minutes.

Transdermal Effects

• Onset: Up to 30 Minutes
• Peak: 2 Hours