Which medication should be avoided in patients with hypertrophic cardiomyopathy?

Patients with hypertrophic cardiomyopathy (HCM) can experience dynamic left ventricular outflow tract obstruction, which is exacerbated by factors that decrease preload or cause vasodilation, as these can lower blood pressure and worsen the obstruction. Nitrates, which are vasodilators, should be avoided in these patients for this reason. They can lead to reduced venous return and potentially worsen the obstruction by lowering systemic vascular resistance, ultimately leading to worsening symptoms like exertional dyspnea, angina, or syncope.

In contrast, beta blockers and disopyramide can be beneficial in managing HCM. Beta blockers reduce heart rate and myocardial contractility, which can help decrease the outflow tract obstruction and improve symptoms. Disopyramide can also have negative inotropic effects and provide some relief from the symptoms associated with HCM. Calcium channel blockers, particularly non-dihydropyridines, may also be used cautiously in HCM for their negative inotropic effects which can help with obstruction management, although they should be used with caution as they may cause significant hypotension if not properly monitored.