A male patient has recently started using a glyceryl trinitrate spray. Which of the following is the MOST appropriate advice to give?

• A. Sit down when using GTN spray
• B. Exhale forcefully into the spray before use
• C. Hold the spray under the tongue for 60 seconds
• D. Eat a carbohydrate-rich snack after spraying

Answer: (A)

Glyceryl trinitrate (nitroglycerin) spray works quickly to dilate blood vessels, which can sharply lower blood pressure. That drop can make you lightheaded or faint, especially when you first start using it. Sitting down before using the spray helps you stay safe if you feel dizzy, reducing the risk of a fall or injury.

Exhaling forcefully into the spray isn’t how it’s used and can irritate the throat or not aid absorption. The spray should be placed under the tongue and allowed to dissolve; holding it for a long time isn’t necessary. There’s no benefit to eating a carbohydrate-rich snack after spraying.