Glyceryl Trinitrate (nitroglycerine)

Introduction: Glyceryl Trinitrate (nitroglycerine) is used to treat and prevent heart-related chest pain (angina). Angina occurs when the heart muscle is not getting enough blood. This medicine works by relaxing and widening blood vessels so blood can flow more easily to the heart.

How it works: Glyceryl trinitrate acts on the enzyme nitric oxide stimulating guanylate cyclase in the vascular smooth muscle cells resulting in the relaxation of smooth muscles. It reduces venous return (preload) and facilitates subendocardial blood flow with redistribution into ischaemic areas. It relieves coronary vasospasm and dilates arterioles reducing afterload.

Important Information: This medicine can cause tolerance - follow prescribed dosing schedule. Severe headache may occur. Do not use with phosphodiesterase type-5 inhibitors (sildenafil, tadalafil).

• Stable angina
• Acute relief of angina pectoris
• Prophylaxis of angina
• Acute myocardial infarction
• Control of hypertension during surgery

Anti-anginal drugs

Nitrate Vasodilator

Glyceryl trinitrate acts on the enzyme nitric oxide stimulating guanylate cyclase in the vascular smooth muscle cells resulting in the relaxation of smooth muscles. It reduces venous return (preload) and facilitates subendocardial blood flow with redistribution into ischaemic areas. It relieves coronary vasospasm and dilates arterioles reducing afterload. It is useful for relief and prevention of anginal attacks.

Glyceryl trinitrate releases nitric oxide which relaxes vascular smooth muscle, dilates blood vessels and reduces the workload of the heart.

Oral (SR Tab/Cap):

• 2.6-6.4 mg 3-4 times daily, adjust according to response
• Maximum: 26 mg 4 times daily

Sublingual Tablet (Acute Relief):

• 0.5 mg SL q5min up to 3 times
• Use at first sign of angina

Sublingual Tablet (Prophylaxis):

• 1 tablet 5-10 minutes before activities likely to provoke angina

Sublingual Spray:

• 1-2 spray(s) PRN for angina, may repeat q3-5min, not to exceed 3 sprays in 15 minutes

Intravenous (Acute MI):

• 10-100 mcg/min

* Use as directed by the registered physician

Oral tablet/capsule or sublingual/intravenous. Sublingual: Place under tongue, do not chew or swallow. Spray: Spray onto or under tongue; do not inhale.

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and go back to your regular schedule. Do not double the dose.

Common Side Effects:

• Headache (may be severe)
• Dizziness
• Lightheadedness
• Decreased blood pressure
• Increased heart rate
• Blurred vision
• Paresthesia

Precautions:

• Headache usually goes away after a few days - inform doctor if it persists.
• Tolerance may develop - follow prescribed dosing schedule.
• May cause dizziness or sleepiness - do not drive.
• Avoid alcohol (increases dizziness).
• Do not use with sildenafil or tadalafil (may cause hypotension).

Contraindications:

• Hypersensitivity
• Severe hypotension
• Heart failure
• Marked anaemia
• Hypertrophic obstructive cardiomyopathy
• Cerebral haemorrhage or head trauma
• Raised intracranial pressure
• Concomitant use with phosphodiesterase type-5 inhibitors

Drug Interactions:

• Enhances bioavailability of dihydroergotamine
• May reduce efficacy of heparin, alteplase and noradrenaline
• Aspirin and other NSAIDs may reduce therapeutic response
• Orthostatic hypotension with calcium channel blockers, antihypertensives, phenothiazines and TCAs

Food Interactions:

• Alcohol may cause flushing, increased heart beat, nausea, thirst, chest pain and hypotension (Disulfiram reaction)

Use in Pregnancy: Generally considered safe during pregnancy. Animal studies have shown low or no adverse effects.

Use in Lactation: Probably safe during breastfeeding. Limited data suggests the drug does not represent significant risk to the baby.

Pediatric Use: Safety and efficacy in children have not been established.

Geriatric Use: No specific dosage adjustment is necessary for elderly patients. Use with caution.

Renal Impairment: Probably safe in kidney disease. Dose adjustment may not be needed.

Hepatic Impairment: Limited information available. Please consult your doctor.

Overdose: Overdose may cause severe hypotension, headache, dizziness, nausea, diarrhea. Supportive care should be given.

Storage: Keep below 30°C, away from light and moisture. Keep out of reach of children.

Glyceryl Trinitrate (Nitroglycerine)