nitroglycerin topical (Nitrol, Nitro Bid, NitroBid Topical, glyceryl trinitrate topical, Topical Nitroglycerin)
Classes: Nitrates, Angina
Dosing and uses of Nitrol, Nitro Bid (nitroglycerin topical)
Adult dosage forms and strengths
ointment
- 2%
Angina Pectoris (Long-Term Prophylaxis)
0.5-2 inches applied in am and 6 hours later to truncal skin
Congestive Heart Failure
1.5 inches, increase by 0.5-1 inch up to 4 inches, q4hr
Pediatric dosage forms and strengths
Safety and efficacy not established
Nitrol, Nitro Bid (nitroglycerin topical) adverse (side) effects
Frequency not defined
Headache
Hypotension
Tachycardia
Dizziness
Lightheadedness
Blurred vision
Flushing
Nausea/vomiting
Nervousness
Xerostomia
Topical allergic reactions
Serious
- Methemoglobinemia (rare)
- Syncope
- Prolonged bleeding time
- Exfoliative dermatitis
- Unstable angina
- Rebound hypertension
- Thrombocytopenia
Warnings
Contraindications
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
Cautions
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
Use supportive treatment in overdose
Pregnancy and lactation
Pregnancy category: C
Lactation: not known whether the drug crosses into breast milk, use caution
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Nitrol, Nitro Bid (nitroglycerin topical)
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
Pharmacokinetics
Half-Life elimination: 1-4 min
Antianginal effects: 30 min
Hemodynamic effects: Within 1 hr
Duration antianginal effects: Up to 7 hr (topical)
Hemodynamic effects: 3-6 hr
Peak Plasma Time: 3-4 hr
Protein Bound: 60%
Vd: 3 L/kg
Metabolism: Mainly in liver, extrahepatic sites: vascular wall, RBC
Metabolites: 1,3-glyceryl dinitrate, 1,2-glyceryl dinitrate, and glyceryl mononitrate (inactive)
Clearance: 5.5-11 L/min
Excretion: Urine
Dialyzable: No