Nitrates (Nitroglycerine, Depo-Nit, Nitrostat, Nitrol, Nitro-Bid)

Nitrates are used for the management of acute episodes of AD as they relax vascular smooth muscle, thus producing vasodilation on peripheral arteries and veins. Dilation of post-capillary vessels, including large veins, promotes peripheral pooling of blood and reduces venous return to the heart, thereby reducing left ventricular end-diastolic pressure (pre-load) and arterial blood pressure. Further, arteriolar relaxation reduces systemic vascular resistance, which leads to reduced arterial pressure (after-load). If an individual with SCI and acute AD has used sildenafil within the previous 24 hours the use of an alternative short acting, rapid-onset antihypertensive agent is recommended. Nitrates are the second most commonly used agent after nifedipine for management of AD in individuals with SCI (Consortium for Spinal Cord Medicine, 2001; Braddom & Rocco 1991). However, with the exception of one case report with intravenous use of nitroprusside (Ravindran et al. 1981) and expert opinions (Consortium for Spinal Cord Medicine, 2001), no studies exist to support their use in SCI.

Conclusion

There is level 5 evidence (from clinical consensus) that supports the use of nitrates in acute management of AD (Consortium for Spinal Cord Medicine, 2001; Braddom & Rocco 1991), but there are no clinical studies testing the use of nitrates in the acute management of AD in people with SCI.