What is Isosorbide Dinitrate Tablets ?
Isosorbide dinitrate is a medication used to prevent and treat chest pain (angina) in people with heart conditions like coronary artery disease. It belongs to a class of drugs known as nitrates.
Isosorbide dinitrate works by relaxing and widening the blood vessels, which allows for easier blood flow and reduces the workload on the heart. This helps to relieve angina symptoms, such as chest pain or discomfort.
Isosorbide Dinitrate Tablets Use
- Relaxing Blood Vessels: Isosorbide dinitrate belongs to a class of drugs known as nitrates. It works by relaxing and dilating (widening) the blood vessels. This dilation allows blood to flow more easily through the arteries and veins, reducing the heart’s workload and increasing the supply of oxygen to the heart muscle.
- Angina Treatment: Isosorbide dinitrate is used to provide immediate relief from angina attacks. It can also be used prophylactically (preventatively) before activities that might trigger angina, like exercise or stressful situations.
- Regular Use: In some cases, a healthcare provider may prescribe isosorbide dinitrate for regular use, particularly if a person experiences angina frequently. This helps maintain a more consistent level of blood flow and can reduce the frequency and severity of angina episodes.
Isosorbide Dinitrate Tablets – Mechanism of Action and Pharmacology
- Mechanism of Action:
- Vasodilation: Isosorbide dinitrate primarily works by dilating (widening) blood vessels, especially the veins. This leads to a reduction in both preload and afterload on the heart.
- Preload Reduction: By dilating the veins, isosorbide dinitrate reduces the amount of blood returning to the heart (venous return). This decreases the volume of blood that the heart needs to pump, which reduces the work the heart has to do.
- Afterload Reduction: It also has a mild effect on arterial smooth muscle, which reduces the resistance against which the heart pumps (systemic vascular resistance). This further eases the heart’s workload.
- Coronary Blood Flow: Isosorbide dinitrate can also lead to improved blood flow in the coronary arteries. This is because it can dilate the coronary arteries, which are the blood vessels that supply the heart muscle itself.
- Reduction of Myocardial Oxygen Demand: By reducing the heart’s workload (preload and afterload reduction) and increasing blood flow to the heart, isosorbide dinitrate can help reduce the oxygen demand of the heart muscle. This is particularly important in angina, where the heart’s oxygen supply-demand balance is compromised.
- Pharmacology:
- Absorption: Isosorbide dinitrate can be taken orally in tablet form. It is well-absorbed through the gastrointestinal tract.
- Metabolism: In the body, isosorbide dinitrate is converted into its active form, isosorbide-5-mononitrate (ISMN), primarily by liver enzymes. This active metabolite is responsible for the vasodilatory effects.
Isosorbide Dinitrate Tablets – Side-effects
- Headache: This is one of the most common side effects. It is usually a result of the dilation of blood vessels in the brain.
- Dizziness or Lightheadedness: This can occur, especially when standing up quickly. It’s related to the vasodilatory effects of the medication.
- Flushing or Redness of the Skin: This is due to increased blood flow near the skin’s surface.
- Nausea or Vomiting: Some people may experience mild gastrointestinal upset.
- Weakness or Fatigue: This can occur, especially if blood pressure drops significantly.
- Palpitations or Rapid Heartbeat: Some individuals may experience an awareness of their heartbeat.
- Methemoglobinemia: This is a rare but serious condition where there’s a higher than normal level of methemoglobin in the blood. It can cause symptoms like bluish discoloration of the skin, shortness of breath, fatigue, and dizziness.
- Tolerance: Prolonged use of isosorbide dinitrate can lead to tolerance, where higher doses may be needed to achieve the same effect.
- Allergic Reactions: Although rare, some people may be allergic to isosorbide dinitrate. Signs of an allergic reaction can include rash, itching, swelling, severe dizziness, and difficulty breathing.
- Hypotension (Low Blood Pressure): In some cases, isosorbide dinitrate can cause a significant drop in blood pressure, which may lead to symptoms like dizziness, fainting, or blurred vision.
- Increased Intracranial Pressure: This can be a concern in individuals with head injuries or certain neurological conditions.
- Vision Changes: Some individuals may experience vision problems, such as blurred vision.
