Isorey Special Precautions

Use with caution: Isosorbide dinitrate should be used with caution and under medical supervision in patients with hypothyroidism, hypothermia, malnutrition, severe liver or renal disease, and in those with orthostatic hypotension.
Tolerance: The development of tolerance (reduced efficacy) and cross-tolerance to other nitrate-type drugs has been reported. To prevent a decrease or loss of effect, continuously high dosages should be avoided.
Monitoring of blood pressure and pulse: Blood pressure and pulse should be regularly monitored, and the dose adjusted according to the patient's clinical response.
Hypoxemia: Caution is advised in patients with hypoxemia or ventilation/perfusion imbalance due to lung disease or ischemic heart failure. As a potent vasodilator, isosorbide dinitrate may increase perfusion to poorly ventilated areas, potentially worsening the ventilation/perfusion imbalance and further reducing arterial oxygen partial pressure.
Alcohol: Alcohol should be avoided during treatment, as it may potentiate the hypotensive and vasodilatory effects of isosorbide dinitrate.
Phosphodiesterase inhibitors: Patients receiving maintenance therapy with isosorbide dinitrate must not use phosphodiesterase inhibitors (e.g., sildenafil, tadalafil, vardenafil). Therapy should not be interrupted to take these products, as this may increase the risk of angina attacks. Acute therapy with isosorbide dinitrate must not be administered to patients who have recently taken phosphodiesterase inhibitors-24 hours for sildenafil or vardenafil, and 48 hours for tadalafil. Patients should be warned not to take phosphodiesterase inhibitor-containing products during treatment.