Nitrates are a class of drug that causes dilation of the blood vessels in the body. The dilation of blood vessels reduces the blood pressure and the amount of work the heart has to do to circulate blood. Nitroglycerin was used in the management of chest pain as early as 1879.
Now, nitrates can be given to CHF patients to reduce symptoms. Nitrates can be administered in many forms, including sublingual, oral, topical, and intravenously. When given chronically, nitrate therapy in CHF improves a patient’s exercise tolerance. In combination therapy with other blood vessel dilators such as hydralazine, nitrates reduce mortality, although to a lesser extent than the ACE inhibitor enalapril.
When treating pulmonary edema, intravenous or sub-lingual nitrates are first-line agents. When CHF is severe and not responding to standard medical therapy, a short course of intravenous nitroglycerin can help break the vicious spiral of CHF.
Giving nitrates continually can result in their being less effective. Because this tolerance occurs, doctors recommend a nightly nitrate-free interval when prescribing nitrates for CHF in order to maintain maximal benefit during the hours of activity. The dosing can be in-creased later as necessary. Common examples of nitrate medications are:
Generic Name Brand Name
nitroglycerin Nitro-Dur, Nitrostat
isosorbide dinitrate IMDUR, Isordil
isosorbide mononitrate ISMO, Monoket
Side effects from nitrates are few, regardless of the route of administration. The most common adverse effects are:
- Low blood pressure (hypotension)
- Headache
- Nausea
- Slow heartbeat (bradycardia)
- Skin reactions (caused by topical nitrates)