Active ingredient
Isosorbiddinitrate (ISDN)
Mode of action
Isosorbide dinitrate belongs to the group of nitrates from which nitric oxide (NO) can be released after absorption into the body. Nitric oxide leads to dilation of blood vessels (vasodilation), especially of the veins and larger coronary arteries. Nitrates thus lead to a reduction in the so-called preload, i.e. the volume of blood that accumulates in the venous system in front of the heart and has to be pumped by the heart.
This is important, for example, in patients with cardiac insufficiency, as the heart is no longer “strong” enough to pump the accumulated volume. Nitrates can help to relieve the heart a little and reduce the oxygen demand. However, they are not the treatment of choice for heart failure because, unlike other drugs, they do not have a life-prolonging effect.
Furthermore, nitrates lead to an improved blood flow in the coronary arteries, which plays a decisive role in patients with coronary heart disease (CHD). Depending on the type of application, ISDN has an effective duration of 30 minutes to 12 hours. In the case of sublingual (under the tongue) administration, the effect occurs after about 1 minute.
Indications
Isosorbide dinitrate is used in coronary heart disease (CHD), especially in acute attacks of angina pectoris (chest tightness), in myocardial infarction, and in acute and chronic heart failure.
Side effects
A typical side effect of nitrates is the so-called “nitrate headache”, which is caused by dilatation of brain vessels (vasodilatation of intracranial vessels) and often resolves itself in the course of therapy. It can also lead to a drop in blood pressure (hypotension) and an increase in heart rate (tachycardia), especially after getting up from a lying position (orthostatic hypotension). Other possible side effects include flushing, allergic reactions, nausea, vomiting and others.
Please note the “nitrate tolerance”, which occurs with all nitrates that are activated by enzymes. With a continuous supply, the effect weakens within 24-48 hours. In order to avoid this, a nitrate-free interval should be observed regularly.
