nitroglycerin transdermal (Rx)

Common

Headache

Hypotension

Tachycardia

Dizziness

Lightheadedness

Blurred vision

Flushing

N/V

Nervousness

Xerostomia

Topical allergic reactions

Serious

Methemoglobinemia (rare)

Syncope

Prolonged bleeding time

Exfoliative dermatitis

Unstable angina

Rebound hypertension

Thrombocytopenia

Contraindications

Hypersensitivity to organic nitrates or adhesives

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

Concomitant administration with guanylate stimulator riociguat (may cause hypotension)

Severe anemia

Cautions

Alcohol use, increased ICP (eg, head trauma, cerebral hemorrhage-potential contraindication), hyperthyroidism, hypertrophic cardiomyopathy, increased IOP, postural hypotension, volume depletion, low systolic BP

Benefits of transdermal nitroglycerin in patients with acute myocardial infarction or congestive heart failure have not been established

Transdermal system should not be used to treat acute angina attacks

Severe hypotension, particularly with upright posture, may occur with even small doses of nitroglycerin, particularly in the elderly; use caution

Nitrate therapy may aggravate angina caused by hypertrophic cardiomyopathy, particularly in the elderly

Arcing may occur if defibrillator discharged through paddle electrode overlying transdermal patch

Discarded patches should be kept out of reach of children and pets

Chest pain, acute myocardial infarction, and even sudden death reported during temporary withdrawal of nitrates from industrial workers with long-term exposure to unknown high doses of organic nitrates

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.

Mechanism of Action

Organic nitrate which causes systemic venodilation, decreasing preload

Cellular mechanism: nitrate enters vascular smooth muscle & converted to nitric oxide (NO) leading to activation of cGMP & vasodilation

Pharmacokinetics

Half-Life: 12-33 min

Onset: 60 min

Duration: 10-12 hr

Bioavailability: 75%

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