Nitroglycerin 2% Topical
Indications
Nitroglycerin 2% Topical is used for:
Angina Pectoris, Congestive Heart Failure
Adult Dose
Topical/Cutaneous
Stable angina
Adult: As 2% oint: Apply 0.5-2 inches on a convenient area of the skin bid or 3-4 hrly if necessary; cover the area after application.
Congestive Heart Failure
1.5 inches, increase by 0.5-1 inch up to 4 inches, q4hr
Child Dose
Safety and efficacy not established
Renal Dose
Administration
Contra Indications
Hypersensitivity to organic nitrates
Recent use (within several days) of PDE-5 inhibitors (eg, avanafil, sildenafil, tadalafil, or vardenafil) may cause dangerously low hypotension; the time course of the interaction appears to be related to the PDE-5 inhibitor half-life
Riociguat; coadministration may cause hypotension
Narrow angle glaucoma (controversial: may not be clinically significant)
Severe anemia
Precautions
Alcohol use, incr ICP (head trauma, cerebral hemorrhage-potential contraindication), hyperthyroidism, hypertrophic cardiomyopathy, increase IOP, hypotension, volume depletion, low systolic BP
Do not change brands unintentionally as not all are bioequivalent
Treat drug-induced headache with aspirin or acetaminophen
Provide nitrate-free interval (10-12 hr or overnight) to avoid development of tolerance
Discontinue if blurred vision develops
Do not apply with fingers; do not rub or massage
Lactation: not known whether the drug crosses into breast milk, use caution
Pregnancy-Lactation
Interactions
Adverse Effects
Side effects of Nitroglycerin 2% Topical :
Orthostatic hypotension, peripheral oedema, bradycardia, tachycardia flushing, hypotension, syncope, dizziness, headache, light-headedness, nausea, vomiting, xerostomia, weakness, paraesthesia, diaphoresis, dyspnoea, rhinitis, pharyngitis, allergic reaction.
Mechanism of Action
Organic nitrate which causes systemic venodilation, decreasing preload
Cellular mechanism: nitrate enters vascular smooth muscle and converted to nitric oxide (NO) leading to activation of cGMP & vasodilation
Relaxes smooth muscle via dose-dependent dilation of arterial and venous beds to reduce both preload and afterload, and myocardial O2 demand
Also improves coronary collateral circulation
Lower BP, increase HR, occasional paradoxical bradycardia