Glyceryl Trinitrate (GTN) |
Presentation |
• 0.6mg tablets • Transdermal GTN Patch (0.4mg/hr) |
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Pharmacology |
• Principally, 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 afterload) • The effects of the above are: - reduced myocardial oxygen demand - reduced systolic, diastolic and mean arterial blood pressure, whilst usually maintaining coronary perfusion pressure - Mild collateral coronary arterial dilatation may improve blood supply to ischaemic areas of myocardium - Mild tachycardia secondary to slight fall in blood pressure • Uterine Quiescence in pregnancy |
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Metabolism |
• By the liver | ||||||||||||||||||||||||||||||||||||
Primary Emergency Indications |
• Chest pain associated with Acute Coronary Syndrome Adult • Acute Pulmonary Oedema Adult • Hypertension associated with Acute Coronary Syndrome Adult • Autonomic Dysreflexia Adult • Preterm Labour: (consult) Obst |
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| • Known hypersensitivity • Systolic blood pressure <110 (tablet) • Systolic blood pressure <90 (patch) • Sildenafl “Viagra” or Vardenafil “Levitra” administration in the previous 24 hr. or Tadalafil “Cialis” administration in the previous 4 days (PED5 inhibitors) • Heart rate >150 • Bradycardia HR <50 (excluding Autonomic Dysreflexia) • Ventricular Tachycardia • Inferior STEMI with systolic BP <160 • Right Ventricular Infarct |
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Precautions |
• No previous administration • Elderly Pts • Recent acute myocardial infarction • Concurrent use with other tocolytics |
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Route of Administration |
• Buccal/Sub-lingual • Transdermal • IV Infusion - interhospital transfer only |
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Side Effects |
• Tachycardia • Hypotension • Headache • Skin flushing (uncommon) • Bradycardia (occasionally) |
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Special Notes |
• Storage: Glyceryl Trinitrate is susceptible to heat and moisture. - Make sure that tablets are stored in their original, light-resistant, tightly sealed bottles. - tablets should be discarded and replaced after 1 month. - The foil pack of the patches should be intact. - patches should be discarded prior to use by date. • Do not administer the patient's own medication, as its storage may not have been in optimum conditions or may be old. • Since both men and women can be prescribed "VIAGRA", "LEVITRA" or "CIALIS", all patients should be asked if and when they last have had the drug to determine if Glyceryl Trinitrate is contraindicated. • Glyceryl Trinitrate by intravenous infusion may be required for an interhospital Transfer as per Doctor's orders . - The dose is to be prescribed and signed by the referring hospital medical officer. Usually in the range of 5mcg/min to 200mcg/min and increased by 3-5mcg/min. |
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Therapeutic Effect |
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