nitroglycerin transmucosal (glyceryl trinitrate transmucosal, Nitrogard, Transmucosal Nitroglycerin)
Classes: Nitrates, Angina
Dosing and uses of Glyceryl trinitrate transmucosal, Nitrogard (nitroglycerin transmucosal)
Angina Pectoris (Long-Term Prophylaxis)
Initially: 1 mg between lip/gum or cheek/gum q8hr (q5hr during waking hour), then increase to 2 mg q8hr, while awake
Renal Failure
CrCl: 10-50 mg/min: Administer q24-72hr
CrCl<10 mL/min: Administer q72-96hr
Pediatric dosage forms and strengths
Not FDA approved
Geriatric dosage forms and strengths
Angina Pectoris (Long-Term Prophylaxis)
Initially: 1 mg between lip/gum or cheek/gum q8hr (q5hr during waking hour), then increase to 2 mg q8hr, while awake
Glyceryl trinitrate transmucosal, Nitrogard (nitroglycerin transmucosal) adverse (side) effects
Common
Headache
Hypotension
Tachycardia
Dizziness
Lightheadedness
Blurred vision
Flushing
N/V
Nervousness
Xerostomia
Serious
Methemoglobinemia (rare)
Syncope
Prolonged bleeding time
Exfoliative dermatitis
Unstable angina
Rebound hypertension
Thrombocytopenia
Warnings
Contraindications
Hypersensitivity, acute MI, severe anemia
Recent (last 24 hr) Sildenafil (Viagra) or other PDE5 inhibitor use: potential for dangerous hypotension
Severe anemia
Recent use (last 24 hr) sildenafil (Viagra), tadalafil (Cialis), or vardenafil (Levitra) or other phopsphodiesterase-5 inhibitor: potential for dangerous hypotension
Narrow angle glaucoma (controversial: May not be clinically significant)
Cautions
MI or CHF, alcohol use, increased ICP (eg, head trauma, cerebral hemorrhage; potential contraindication), hyperthyroidism, hypertrophic cardiomyopathy, increased IOP, postural 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
Controlled release product
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 Glyceryl trinitrate transmucosal, Nitrogard (nitroglycerin transmucosal)
Half-Life: 1-4 min
Onset: 1-2 min
Duration: upto 5 hr
Bioavailability: 60-75%
Protein Bound: 11-60%
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
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
