Isosorbide

Severe hypotension can occur; paradoxical bradycardia and increased angina pectoris can accompany hypotension. Orthostatic hypotension can also occur; ethanol can accentuate this. Use with caution in volume depletion and hypotension, and use with extreme caution with inferior wall MI and suspected right ventricular infarctions. Severe hypotension, particularly with upright posture, may occur with even small doses.

Nitrates may precipitate or aggravate increased intracranial pressure and subsequently may worsen clinical outcomes in patients with neurologic injury (eg, intracranial hemorrhage, traumatic brain injury) (Rangel-Castilla 2008). Disease-related concerns:

Not recommended in patients with acute MI or HF (cannot easily reverse effects if adverse events develop).

Avoid use in patients with HCM with outflow tract obstruction; nitrates may reduce preload, exacerbating obstruction and cause hypotension or syncope and/or worsening of heart failure (ACCF/AHA [Gersh 2011]). Concurrent drug therapy issues:

Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information. Other warnings/precautions:

Appropriate dosing intervals are needed to minimize tolerance development. Tolerance can only be overcome by short periods of nitrate absence from the body. Dose escalation does not overcome this effect. When used for HF in combination with hydralazine, tolerance is less of a concern (Gogia 1995).