Nitroglycerin- call 911 after first or third dose?

[Alwayslearning1234]

Hi everyone,

I see a lot of conflicting information about outpatient SL Nitroglycerin use in pharmacology textbooks, with two main points.
1) If having chest pain, take 1st of Nitro. If pain unrelieved after 5 min, call 911 and take second dose (faster EMS response)
2) If having chest pain, take 1st dose of Nitro, if pain unrelieved in 5 min, take 2nd dose. If pain unrelieved, take 3rd dose, then call 911. (delayed time for EMS response)

Both arguments have dose 1 dose every 5 minutes (3 dose max within 15 minutes).

Found this article from Pharmacist's Letter in 2016,

1. Remind patients to call 911 if chest pain doesn't get better within 5 minutes after the FIRST dose...to speed up access to emergency care. Advise patients to take no more than 3 doses in 15 minutes.
   1. https://pharmacist.therapeuticresearch.com/Content/Articles/PL/2016/Nov/Explain-How-GoNitro-Compares-to-Other-Sublingual-Nitroglycerin-Forms-for-Angina

2. However, 2012 guidelines for Stable Ischemic Heart Disease state this,
All patients with SIHD should be prescribed sublingual nitroglycerin tablets or nitroglycerin spray for immediate relief of angina. Most patients respond within 5 minutes of taking 1 to 2 sublingual dose(s) of 0.3 to 0.6 mg. Nitroglycerin spray is available in a 0.4-mg metered-dose canister that dispenses 200 doses. The tablets should be placed under the tongue and not swallowed. If the spray is used, it should be applied to the tongue and not swallowed or inhaled. If additional doses are necessary, they should be taken at 5-minute intervals, for a maximum dose of #1.2 mg within 15 minutes. During this timeframe, if relief does not occur, the patient should seek immediate medical attention.

https://www.ahajournals.org/doi/pdf/10.1161/CIR.0b013e318277d6a0

Does anyone have any recent literature on which rule to use?
To me, it makes sense to stay on the side of caution and call if first dose is insufficient

I can't seem to find any evidence or literature, just a bunch of various hospitals with patient education pamphlets.

THANK YOU!

---

Members don't see this ad.

 

[shouldigomd]

More important than the number of doses is the pattern of pain. A change in someones anginal pattern is indication for evaluation. In my experience I advise my patients to call 911 if new / unusual chest pain or in the setting of stable angina .... if unrelieved after 2nd dose.