Effective Angina Pectoris Treatment: Calculating Nitroglycerin Dosage for Acute Chest Discomfort

When a client experiences acute chest discomfort and shortness of breath, it can be a sign of a serious cardiac issue. Acute angina pectoris is a condition that requires immediate attention. In this situation, the healthcare provider orders intravenous (IV) nitroglycerin at a specific rate for effective treatment. The prescribed nitroglycerin dosage is 75 mg in 500 mL of 5% Dextrose Water to be infused at a rate of 100 micrograms per minute (mcg/min). To ensure that the client receives the correct treatment, it is vital to calculate the pump’s infusion rate in milliliters per hour (mL/hr). In this article, we will guide you through the steps necessary to determine the appropriate rate for nitroglycerin infusion in the treatment of acute angina pectoris.

Understanding Angina Pectoris and Cardiac Emergencies

Angina pectoris, commonly known as angina, is a condition characterized by chest discomfort or pain resulting from reduced blood flow to the heart muscle. It can occur suddenly and is often a symptom of underlying coronary artery disease. When acute angina pectoris is diagnosed, swift medical intervention is essential to alleviate symptoms and prevent further complications.

The Role of Nitroglycerin in Angina Pectoris Treatment

Nitroglycerin is a vasodilator that helps relax and widen blood vessels. It is commonly used in the treatment of angina pectoris to reduce the heart’s workload and improve blood flow to the heart muscle. Nitroglycerin helps relieve chest pain and discomfort.

Calculating the Nitroglycerin Infusion Rate

To determine the infusion rate for nitroglycerin, several calculations are required. Here are the key steps:

  1. Calculate the Total Micrograms per Minute: The healthcare provider ordered nitroglycerin to be infused at a rate of 100 mcg/min.
  2. Determine the Total Milligrams per Minute: To convert micrograms to milligrams, divide the total micrograms per minute by 1,000 (since there are 1,000 micrograms in 1 milligram).

    Total Milligrams per Minute = Total Micrograms per Minute / 1,000

    Total Milligrams per Minute = 100 mcg/min / 1,000 = 0.1 mg/min

  3. Calculate the Total Milligrams per Hour: To find the total milligrams per hour, multiply the total milligrams per minute by 60 (since there are 60 minutes in an hour).

    Total Milligrams per Hour = Total Milligrams per Minute x 60

    Total Milligrams per Hour = 0.1 mg/min x 60 = 6 mg/hr

  4. Calculate the Volume of Infusion per Hour: To determine the volume of the nitroglycerin solution to be administered per hour, you need to know the concentration of the solution, which is 75 mg in 500 mL of 5% Dextrose Water.
  5. Calculate the Rate in mL/hr: Divide the total milligrams per hour by the concentration of the solution (in mg per mL) to find the rate in milliliters per hour.

    Rate (mL/hr) = Total Milligrams per Hour / Concentration of Solution (mg/mL)

    Rate (mL/hr) = 6 mg/hr / (75 mg/500 mL) = 40 mL/hr

Given the concentration of the nitroglycerin solution, the nurse should set the infusion pump to deliver nitroglycerin at a rate of 40 mL/hr for the treatment of acute angina pectoris.

Nurse’s Responsibilities in Cardiac Emergency Care

In the treatment of acute angina pectoris and other cardiac emergencies, nurses have critical responsibilities to ensure the patient’s safety and well-being.

  1. Patient Assessment: Conduct a thorough assessment of the patient’s condition, including monitoring vital signs, heart rhythm, oxygen saturation, and the severity of angina symptoms. Pay close attention to any signs of cardiac distress.
  2. Informed Consent: Ensure that the patient or their caregiver understands the purpose and potential side effects of the medication. Obtain informed consent for treatment.
  3. Medication Preparation: Accurately prepare the medication, considering the prescribed dosage, concentration, and volume.
  4. Dosage Calculation: Calculate the precise dosage and infusion rate, as demonstrated above, to ensure the patient receives the appropriate amount of nitroglycerin.
  5. Administration: Administer the medication via the intravenous route at the calculated rate.
  6. Monitoring: Continuously monitor the patient’s response to treatment, vital signs, heart rhythm, and any potential side effects. Adjust the treatment plan as needed.
  7. Documentation: Maintain accurate and comprehensive documentation, noting the medication dosage, vital signs, and the patient’s response to therapy. This documentation is essential for the patient’s ongoing care.


Accurate medication administration is crucial in the treatment of acute angina pectoris and other cardiac emergencies. By following the steps outlined in this article, nurses can ensure that patients receive the appropriate dosage of nitroglycerin, aiding in the effective management of angina symptoms and potentially preventing more severe cardiac events. This meticulous approach is essential for providing optimal care to patients in critical medical conditions.


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