Before administering isosorbide mononitrate, which assessment is most important?

• A. Assess electrolytes.
• B. Measure BUN and creatinine.
• C. Assess blood pressure.
• D. Assess mental status.

Answer: (C)

The key idea is that nitrates like isosorbide mononitrate cause vasodilation, which can lower blood pressure. Because of this, checking the patient’s blood pressure before administration is essential to prevent dangerous hypotension or fainting. If the systolic pressure is too low or the patient already shows signs of hypotension, the dose should not be given and the provider should be informed. This monitoring helps ensure the drug provides anti-anginal benefit without compromising perfusion. (Also keep in mind that combining nitrates with phosphodiesterase inhibitors can cause a much more severe drop in blood pressure.)