GTN Flashcards
Presentation
0.3mg tablet
0.6mg tablet
transdermal patch 50mg (0.4mg/hr release)
Pharmacology
Principally a vascular smooth muscle relaxant.
Actions:
- venous dilation promotes venous pooling and reduces venous return to the heart (reduces preload)
- arterial dilation reduces systemic vascular resistance and arterial pressure (reduces afterload)
The effects are:
- reduced myocardial O2 demand
- reduced systolic, diastolic and mean arterial pressure, whilst usually maintaining coronary perfusion
- mild collateral coronary arterial dilation may improve blood supply to ischaemic areas of the myocardium
- mild tachycardia secondary to slight fall in BP
- preterm labour: uterine quiescence in pregnancy
Metabolism
By the liver
Primary emergency indications
- chest pain with ACS
- Acute LVF
- Hypertension associated with ACS
- Autonomic dysreflexia
- Preterm labour (consult)
Contraindications
- BP <100mmHg
- HR >150bpm
- HR <50bpm
- Taladafil (cialis) administration/current (PDE5 inhibitors)
- Ventricular tachycardia
- Riociguat (current use) (treat pulmonary hypertension)
Precautions
- no previous administration
- elderly patients
- recent MI
- concurrent use with other tocolytics
Route of administration
SL
Buccal
Transdermal
Infusion (interhospital transfer only)
Side effects
- Tachycardia
- Hypotension
- Headache
- Skin flushing (uncommon)
- Bradycardia (occasionally)
Special notes
- Susceptible to heat and moisture, store in original light resistant bottles or foil packaging.
- do not administer patient’s own tablets, as may not have been stored correctly
- patches should be discarded prior to use-by date
- both men and women can be prescribed cialis
- GTN infusion may be required for interhospital transfer as per treating doctors orders
S/L effects:
Onset: 30seconds-2 mins
Peak: 5-10mins
Duration: 15-30mins
Intravenous effects
Onset: 30 seconds-1min
Peak: 3-5mins
Duration: 15-30mins
Transdermal effects
Onset: up to 30mins
Peak: 2hrs
