Nitroglycerin (Nitrostat)

Question 1

Drug Classification

Answer 1

Vasodilator/Nitrate

Question 2

Mechanism of Action

Answer 2

Nitroglycerin is a pro-drug which must be de-nitrated to form the active metabolite nitric oxide (NO). Then, NO activates the conversion of GTP →cGMP + 2Pi in vascular smooth muscle cells (VSMC). cGMP activates a cascade of reactions that cause a reduction in intracellular Ca2+, VSMC relaxation (in arterioles) and decreased cardiac preload and afterload.

Question 3

Pharmacokinetics

Answer 3

Onset of Action = 1-2 minutes IV, 1-3 minutes SL, 30 minutes topical
Peak Effects = 5-10 minutes SL, varies topical
Duration of Effect = 20-30 minutes SL, 3-6 hours topical
Half-Life = 1-4 minutes

Question 4

Indications

Answer 4

Chest pain associated with angina or MI

Acute pulmonary edema/CHF

Question 5

Contraindications

Answer 5

Shock, hypotension
Increased ICP
Children under 12
ED drugs w/in 48 hour

Question 6

Side effects

Answer 6

Hypotension, tachycardia, weakness, dizziness, headache, nausea & vomiting, rash, dry mouth

Question 7

Dose

Answer 7

Spray (ADULT): 0.4mg SL q3-5min until effect achieved or BP drops (max 3x25min)

Paste (ADULT): 1-2 inches Topical

Tablet (ADULT): 0.4mg SL q3-5min until effect achieved or BP drops (max 3x25min)

Question 8

Precautions

Answer 8

Expect headache from cerebral vasodilation
Routine use may cause tolerance
12-lead ECG prior to administration
Doesn’t improve morbidity or mortality, is used only to treat pain
Use with extreme caution in Inferior Wall MI

Question 9

Drug Interactions

Answer 9

Orthostatic hypotension with β-blockers, severe hypotension with alcohol