Intranasal administration of nitroglycerin

During anesthesia, the presence of surgical drapes, an endotracheal tube, oral airway, esophageal stethoscope, and a temperature probe render topical or sublingual administration of NTG difficult. In addition, premedication with atropine or other antisialogogue may inhibit the dissolution and absorption of sublingual tablets. Clinical experience suggested that this route of administration of NTG provided a rapid onset of action with a predictable and consistent therapeutic effect. Therefore, the following study was designed to determine the pharmacokinetics of an intranasal NTG solution. In all patients, the desired clinical effect, namely a lowering of the pulmonary artery end-diastolic pressure and/or improvement in S-T segment changes, was seen within two minutes of administration. No patient became hypotensive, tachycardic, or required therapeutic intervention to reverse the effect of NTG. NTG levels were found to be highest in central venous blood, reaching a peak at 1-2 min after administration. Arterial and peripheral venous levels were found to be progressively lower, peaking at 1-2 and 2 min, respectively. Blood levels fell rapidly as a monoexponential function and were barely detectable at 16 min.