NITROGLYCERIN (NTG)
W. G. Franklin, M.D.
- NTG is an arterial dilator (widens arteries) which:
- Increases coronary artery blood flow
- Reduces the blood pressure (thus reducing the workload of the heart)
- Generally used at the time of symptoms to relieve discomfort or shortness of breath due to angina
- Angina is the term for pressure due to decreased blood flow to heart muscle
- The feeling is not usually described as pain but could progress to pain
- Some people have discomfort (pain) in their shoulders, arms, neck, jaw back or abdomen
- Others simply have shortness of breath, called an anginal equivalent
- May also be used ahead of time in anticipation of symptoms, prophylactically
- Before a heavy meal, exercise, sexual relations, or stressful situation
- Placed under the tongue behind the lower teeth
- Dissolves in 30-60 seconds, works in 1 to 5 minutes, lasts 30 minutes
- May be repeated in 5 minutes twice (total of 3 times in 15 minutes) if not dizzy and symptoms still persist
- If BP is generally less than 110 it is best to take NTG lying down
- Side effects may include:
- Headache (from widening of arteries to head)
- Consider Tylenol (acetomeniphen) or Advil (ibuprofen)
- Dizziness (from lowering BP)
- Drink fluids, be careful getting up (wears off in 30 minutes or less)
- Headache (from widening of arteries to head)
- NTG comes in different strengths (not always stocked in each drugstore):
- .6 mg (1/100 gr.) .4mg (1/150) .3mg (1/200) .15mg (1/400)
- may be broken into smaller pieces with thumbnail
- use 1 or more pieces in 5 minutes to relieve discomfort and limit headache if present
- if discomfort is still present after 3 NTG (taken in 15 minutes) then calling 911 is advisable
- the rescue squad will administer O2, perform an EKG, and judge whether to proceed to the Emergency Room
- many doctors and paramedics ask patients after 1 or 2 NTG: "Is the pain still there?'
- patients often respond "no" if they are feeling better but still have discomfort, pressure, or an abnormal feeling.
- since the heart is still straining for minutes after discomfort resolves, the goal is total resolution of the bad feeling or shortness of breath
- thus, ask yourself if your chest or back, etc, feel "completely normal."
- If not "completely normal" consider further NTG whether at home, in the ambulance, or in the ER.
- isosorbide (Isordil) and Imdur are pills of long acting nitrates
- nitrolpaste and Nitrodurr are ointments applied to the skin
- both groups of medicines provide a low level of nitrate for hours
- sublingual NTG should still be taken if symptoms arise
- this provides a high level (bolus) of nitrate for 30 minutes
- one may take 10-20 NTG per day if necessary