nitroglycerin topical (Nitrol, Nitro Bid, NitroBid Topical, glyceryl trinitrate topical, Topical Nitroglycerin)

Dosing and uses of Nitrol, Nitro Bid (nitroglycerin topical)

• Adult
• Pediatric

 

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