What it's for (Indications)
- Glyceryl trinitrate, often prescribed as Angised 0.
- 5mg, is primarily indicated for the acute relief of an attack of angina pectoris (chest pain) due to coronary artery disease.
- It is also utilized for the prophylactic management of angina pectoris, specifically to prevent predictable anginal attacks when administered prior to engaging in physical activities or stressful situations known to precipitate such episodes.
- The rapid onset of action makes it an invaluable immediate intervention for patients experiencing anginal symptoms, helping to quickly alleviate discomfort and improve myocardial oxygen supply-demand balance.
- Its use is focused on the symptomatic management of ischemic heart disease, providing rapid vasodilation to improve cardiac perfusion and reduce workload.
Dosage Information
| Type | Guideline |
|---|---|
| Standard | For the acute treatment of angina pectoris, glyceryl trinitrate sublingual tablets, such as Angised 0.5mg, are typically administered by placing one tablet under the tongue and allowing it to dissolve completely. Patients should sit down immediately upon experiencing chest pain and take the first dose. If anginal pain is not relieved within 5 minutes, a second tablet may be taken. If symptoms persist for another 5 minutes, a third tablet can be administered. A maximum of three tablets should be taken within a 15-minute period. If chest pain continues after the third dose, or if new symptoms such as profuse sweating, shortness of breath, or sudden weakness develop, immediate emergency medical attention (e.g., calling emergency services) is crucial, as this may indicate a myocardial infarction. Patients should be instructed on proper administration and the importance of seeking urgent care if the maximum dose does not alleviate symptoms. |
Safety & Warnings
Common Side Effects
- The most common side effects associated with glyceryl trinitrate are directly related to its potent vasodilatory effects.
- These include headache, which can range from mild to severe ('nitrate headache'), dizziness, lightheadedness, and facial flushing.
- Orthostatic hypotension, characterized by a sudden drop in blood pressure upon standing, leading to faintness or syncope, is also frequently observed and necessitates caution, especially in elderly patients or those with pre-existing hypotension.
- Less common but serious side effects can include reflex tachycardia, which is an increase in heart rate in response to the blood pressure drop, and methemoglobinemia, a rare but potentially life-threatening condition, particularly with high doses or prolonged use.
- Nausea and vomiting are also reported, though less frequently.
- Patients should be advised to sit or lie down when taking the medication to mitigate hypotensive effects.
Serious Warnings
- Black Box Warning: Glyceryl trinitrate (e.g., Angised 0.5mg) does not carry a formal FDA Black Box Warning. However, healthcare professionals and patients must be made aware of several critical safety considerations that warrant heightened vigilance. Foremost among these is the absolute and life-threatening contraindication of concomitant use with phosphodiesterase-5 (PDE5) inhibitors, such as sildenafil, tadalafil, vardenafil, or avanafil. This combination can lead to profound, prolonged, and irreversible hypotension, circulatory collapse, and potentially death. Patients must be explicitly questioned about PDE5 inhibitor use, and they must be instructed to never take these medications together. Furthermore, severe hypotension, particularly in volume-depleted patients or those with pre-existing low blood pressure, can occur, necessitating careful monitoring of blood pressure. Increased intracranial pressure, as seen in head trauma or cerebral hemorrhage, is a contraindication due to the risk of exacerbating brain swelling. Patients with hypertrophic obstructive cardiomyopathy are at risk of increased outflow tract obstruction and worsening symptoms. Reflex tachycardia can occur and may paradoxically worsen angina in some individuals. Patients should be advised about the common occurrence of headaches, which typically subside with continued use, but to report any unusually severe or persistent headaches.
- Patients should be thoroughly educated on potential risks and proper use of glyceryl trinitrate.
- Severe hypotension, especially in volume-depleted individuals or those concurrently receiving other antihypertensive agents, can occur, potentially leading to cardiovascular collapse.
- Concomitant use with phosphodiesterase-5 (PDE5) inhibitors (e.
- g.
- , sildenafil, tadalafil, vardenafil, avanafil), commonly used for erectile dysfunction or pulmonary hypertension, is absolutely contraindicated due to the risk of profound and prolonged hypotension, which can be life-threatening.
- This interaction is critical and must be explicitly communicated.
- Patients with hypertrophic obstructive cardiomyopathy (HOCM) should use nitrates with extreme caution as they may exacerbate outflow tract obstruction.
- Paradoxical bradycardia and increased angina may occur in some patients.
- Tolerance can develop with continuous or frequent use, potentially diminishing its therapeutic efficacy.
- Alcohol consumption can intensify the hypotensive effects of glyceryl trinitrate.
- Patients should be warned about the common occurrence of headache, which is a sign of drug activity, but should not discontinue therapy without consulting a healthcare professional.
How it Works (Mechanism of Action)
Glyceryl trinitrate is an organic nitrate that acts as a potent vasodilator. Upon administration, it is enzymatically converted to nitric oxide (NO) within vascular smooth muscle cells. Nitric oxide then activates guanylate cyclase, an enzyme that catalyzes the synthesis of cyclic guanosine monophosphate (cGMP) from guanosine triphosphate (GTP). Elevated levels of cGMP lead to the dephosphorylation of the myosin light chain in smooth muscle cells, resulting in relaxation. This relaxation primarily affects venous capacitance vessels, leading to venodilation and a significant reduction in venous return to the heart (preload). By reducing preload, myocardial wall tension and oxygen demand are decreased, which is beneficial in relieving angina. Glyceryl trinitrate also causes some dilation of coronary arteries, improving blood flow to ischemic areas of the myocardium, and can relieve coronary vasospasm. The combined effects of reduced preload and improved coronary blood flow contribute to the alleviation of anginal symptoms.
Commercial Brands (Alternatives)
No other brands found for this formula.