Montra Special Precautions

The benefits and safety of ISMN in anginal patients with acute myocardial infarction or congestive heart failure have not been established. Since the effects of ISMN are difficult to terminate rapidly, Montra is not recommended in these settings.
Use with caution in patients who may be volume depleted or who are already hypotensive because severe hypotension, particularly with upright posture, may occur with even small doses of ISMN. Patients with systolic blood pressure <90 mm Hg or >30 mm Hg below baseline generally should not receive nitrates. Hypotension induced by ISMN may be accompanied by paradoxical bradycardia and increased angina pectoris.
Nitrate therapy may aggravate the angina caused by hypertrophic cardiomyopathy.
There is a risk of developing tolerance to the hemodynamic and antianginal effects if higher doses (>120 mg/day) and/or more frequent doses (eg, twice daily) of ISMN are administered. Administer ISMN SR capsules once daily to reduce risk of developing tolerance (see Dosage & Administration).
Tolerance to the individual nitrates and nitrites and cross tolerance among these drugs may occur with repeated, prolonged use. Tolerance to the vascular and antianginal effects of the drugs has been shown in studies, by experience from occupational exposure and in isolated in vitro tissue experiments; such tolerance is a principal factor limiting the efficacy of long-term nitrate therapy. Tolerance to nitrates appears to be associated with high and/or sustained plasma drug concentrations and frequent administrations. There is physical dependence in industrial workers who have had long-term exposure to unknown (presumably high) doses of organic nitrates since chest pain, acute myocardial infarction and even sudden death have occurred during temporary withdrawal of nitrates from these workers.
Although no documented rebound phenomena were reported upon sudden withdrawal of ISMN SR, such abrupt withdrawal is not recommended because of the possibility of severe exacerbation of anginal symptoms.
Headaches or severe hypotension (eg, weakness or dizziness, particularly when arising suddenly from a recumbent position) may occur.
Use with caution in patients with severe cerebral arteriosclerosis.
Use with caution in patients with arterial hypoxia due to anemia. Likewise, caution should be exercised in patients with hypoxemia and a ventilation/perfusion imbalance due to lung disease or ischemic heart failure. Patients with angina pectoris, myocardial infarction or cerebral ischemia frequently suffer from small airways abnormalities (ie, alveolar hypoxia). In these situations, vasoconstriction occurs within the lungs to shift perfusion from areas of alveolar hypoxia to better ventilated regions of the lungs. ISMN, as a potent vasodilator, could reverse this protective vasoconstriction and thus, result in increased perfusion to poorly ventilated areas, worsening of the ventilation/perfusion imbalance and a further decrease in the arterial partial pressure of oxygen.
PDE-5 inhibitors are contraindicated in patients receiving nitrates/nitrites, given regularly or intermittently, since severe, potentially fatal hypotensive episodes may occur. However, the use of organic nitrates/nitrites in patients receiving PDE-5 inhibitors may not be completely avoidable, provided sufficient time has elapsed between the use of PDE-5 inhibitors and administration of nitrates/nitrites. Although it is not known how much time must elapse between the use of sildenafil and administration of nitrate/nitrite, pharmacokinetic data suggest that these latter agents should not be given within 24 hrs of sildenafil administration since an exaggerated hypotensive response is likely; plasma sildenafil concentrations 24 hrs after a dose are substantially lower than peak concentrations.
Exercise caution when engaging in activities requiring mental alertness ie, driving or operating machinery, since patients may experience faintness and/or dizziness.
Use in pregnancy & lactation: Pregnancy Category C. There are no available studies in pregnant women. ISMN should be used in pregnancy only if the potential benefit justifies the potential risk to the fetus. It is not known whether ISMN is excreted in breast milk. Exercise caution when administering Montra to breastfeeding women.
Use in children: The safety and efficacy of ISMN in children have not been established.