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nitroglycerin; NTG; TNG (Tridil, NitroBid, Nitrol, Nitrostat, Deponit, Minitran, NitroDur, Nitropaste, Rectiv)

Indications: - hypertension - acute relief of angina pectoris, unstable angina - prophylaxis for angina pectoris - preferred vasodilator for treatment of heart failure in the setting of acute myocardial infarction - may also be useful in treatment of cardiogenic pulmonary edema - ointment for symptomatic treatment of anal fissures Contraindications: 1) severe bradycardia or tachycardia 2) concurrent use of phosphodiesterase 5 inhibitors a) sildenafil (Viagra) within 24 hours b) tadalafil (Cialis) within 48 hours Caution: 1) hypovolemia 2) constrictive pericarditis 3) hypertension & hypotension 4) increased intracranial pressure Dosage: 1) IV (infusion): Tradenames: Tridil, NitroBid. - mix 50 mg (5 mg/mL, 10 mL) in 250 mL D5W (200 ug/mL) - start at 5 ug/min (1.5 mL/min), max 200 ug/min. 2) ointment - 2% (Nitropaste): Tradenames Nitro-bid, Nitrol. - 0.5-5 inches every 4-8 hours - remove every 8/day (to avoid tolerance) - (15 mg/inch). (30 g, 60 g) - 0.2% & 0.4% (Reactiv) for anal fissures [9] 3) sublingual: Tradename: Nitrostat. - 0.4 mg SL (if no relief after 5 min, call 911) [7] 4) sustained-release: Tradename: NitroBid. - start 2.5 mg PO BID/TID, titrate upward as needed. 5) spray: Tradename: Nitrolingual. - 1-2 oral sprays PRN. 6) transdermal: - 1 patch QD. - Deponit: 0.2, 0.4 mg/hr. - Minitran: 0.1, 0.2, 0.4, 0.6 mg/hr. - Nitro-Dur: 0.1, 0.2, 0.3, 0.4, 0.6, 0.8 mg/hr. - Nitrodisc: 0.2, 0.3, 0.4 mg/hr. - Transderm-Nitro: 0.1, 0.2, 0.4,0.6, 0.8 mg/hr. Conversion: ointment < 1 inch patch 0.4 mg/hr dinitrate 20 mg TID Injection: 5 mg/mL (10 mL) Tabs: (sublingual) 0.15, 0.4, 0.4, 0.6 mg. {tablets useable until expiration date} [6,7] Tabs: (sustained-release) 2.5, 6.5, 9 mg. Storage: - store in orginal container (reason unclear) [10] Pharmacokinetics: 1) onset of action a) immediately following IV administration b) within 2 minutes after sublingual administration c) 20-40 minutes after SR capsule d) 15-60 minutes after application of ointment e) 30-60 minutes after application of patch 2) peak effect a) immediately following IV administration b) within 4-8 minutes after sublingual administration c) 45-120 minutes after SR capsule d) 30-120 minutes after application of ointment e) 60-180 minutes after application of patch 3) duration of action a) 3-5 minutes following IV administration b) 30-60 minutes after sublingual administration c) 4-8 hours after SR capsule d) 2-12 hours after application of ointment e) 18-24 hours after application of patch 4) extensive 1st pass metabolism limits systemic absorbtion 5) metabolized by liver 6) long-term administration may saturate metabolic capacity of the liver, resulting in accumulation & tolerance 7) 1/2life is 2-3 hours Adverse effects: 1) common (> 10%) - headache, flushing, lightheadedness, dizziness, weakness, orthostatic hypotension 2) less common (1-10%) - rash, exfoliative dermatitis 3) uncommon (< 1%) - nausea/vomiting, methemoglobinemia (overdose), reflex tachycardia, perspiration & collapse, bradycardia, coronary vasculature insufficiency, arrhythmias, allergic contact dermatitis, alcohol intoxication 4) other - may cause tolerance & dependence with prolonged use - tingling or burning under the tongue NOT a reliable indicator of potency of sublingual form Drug interactions: - may cause additive hypotension in combination with antihypertensive agents Mechanism of action: 1) converted to nitric oxide (NO, EDRF) by vascular endothelium 2) NO activates guanylate cyclase 3) increases cGMP 4) decreases intracellular Ca+2 5) direct relaxation of smooth muscle, including that in the arteries & veins 6) low concentrations of nitroglycerin produce dilation of the veins that predominates over that of arterioles 7) venodilation results in decreased left & right end diastolic pressures (decreased preload) 8) coronary blood flow increases transiently 9) may inhibit platelet aggregation Notes: - Nitroglycerin was first synthesized in 1846 by Sobero, who observed that a small quantity of the oily substance placed on the tongue elicited a severe headache [1] - In 1879, William Murrell established the use of sublingual nitroglycerin for relief of acute angina.

Interactions

drug interactions drug adverse effects of antihypertensive agents

General

nitrate

Properties

MISC-INFO: elimination route LIVER 1/2life 1-3 MINUTES pregnancy-category C safety in lactation ?

Database Correlations

PUBCHEM cid=4510

References

  1. Gilman et al, eds. Permagon Press/McGraw Hill pg 764
  2. Manual of Medical Therapeutics, 28th ed, Ewald & McKenzie (eds), Little, Brown & Co, Boston, 1995, pg 87,131
  3. The Pharmacological Basis of Therapeutics, 9th ed. Gilman et al, eds. Permagon Press/McGraw Hill, 1996
  4. Drug Information & Medication Formulary, Veterans Affairs, Central California Health Care System, 1st ed., Ravnan et al eds, 1998
  5. Kaiser Permanente Northern California Regional Drug Formulary, 1998
  6. Prescriber's Letter 10(6):33 2003
  7. Prescriber's Letter 12(9): 2005 Detail-Document#: 211102 (subscription needed) http://www.prescribersletter.com
  8. Prescriber's Letter 17(5): 2010 COMMENTARY: Sublingual Nitroglycerin GUIDELINES: Management of Patients with Unstable Angina/ Non-ST-Elevation Myocardial Infarction (ACC/AHA, 2007) GUIDELINES: Management of Patients with ST-Elevation Myocardial Infarction (ACC/AHA, 2004) PATIENT HANDOUT SPANISH VERSION: Lo que usted debe saber acerca de su nitroglicerina de uso sublingual PATIENT HANDOUT: What You Should Know About Your Sublingual Nitroglycerin Detail-Document#: 260503 (subscription needed) http://www.prescribersletter.com
  9. Deprecated Reference
  10. Prescriber's Letter 21(6): 2014 Oral Meds to Keep in Original Containers Detail-Document#: 300622 (subscription needed) http://www.prescribersletter.com