Isosorbide mononitrate Tablets should be used with caution in patients who are suffering from hypothyroidism, hypothermia, malnutrition and severe liver or renal disease.
Isosorbide should be used with caution in patients who have a recent history of myocardial infarction low filling pressures e.g. in acute myocardial infarction, impaired left ventricular function (left ventricular failure), or orthostatic dysfunction. Reducing systolic blood-pressure below 90 mmHg must be avoided.
Symptoms of circulatory collapse may arise after first dose, particularly in patients with labile circulation.
This product may give rise to symptoms of postural hypotension and syncope in some patients. Severe postural hypotension with light-headedness and dizziness is frequently observed after the consumption of alcohol.
Hypotension induced by nitrates may be accompanied by paradoxical bradycardia and increased angina.
Isosorbide mononitrate Tablets contain lactose and therefore should not be used in patients with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption.
In the event of an acute angina attack, a sublingual treatment such as a GTN spray or tablet should be used instead of Isosorbide mononitrate Tablets. The onset of action of Isosorbide mononitrate Tablets is not sufficiently rapid to be useful to treat an acute anginal attack.
If the tablets are not taken as indicated (see section 4.2), tolerance to the medication could develop. The lowest effective dose should be used.
Treatment with Isosorbide mononitrate, as with any other nitrate, should not be stopped suddenly. Both the dosage and frequency should be tapered gradually (see section 4.2)
In patients with decreased gastrointestinal transit time, a decrease in release of the active ingredient may occur.
Patients who undergo a maintenance treatment with Isosorbide mononitrate should be informed that they must not use phosphodiesterase inhibitor-containing products (e.g. sildenafil, tadalafil, vardenafil).
Isosorbide mononitrate therapy should not be interrupted to take phosphodiesterase inhibitor-containing products (e.g. sildenafil, tadalafil, vardenafil), because the risk of inducing an attack of angina pectoris could increase by doing so (see section 4.3 & 4.5).
Hypoxaemia
Caution should be exercised in patients with hypoxaemia and ventilation/perfusion imbalance due to lung disease or ischaemic heart failure.
As a potent vasodilator, isosorbide mononitrate could result in increased perfusion of poorly ventilated areas, worsening of the ventilation/perfusion imbalance, and a further decrease in the arterial partial pressure of oxygen. During treatment with isosorbide mononitrate alcohol should be avoided as it may potentiate the hypotensive effect of isosorbide mononitrate (see section 4.5).