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Monday, February 7, 2011

nitroglycerin

Posted by Sampil 6:00 PM, under | No comments

nitroglycerin
(nye troe gli' ser in)
Intravenous:
Nitro-Bid IV, Nitroject (CAN)
Spray:
Nitrolingual Pumpspray
Sublingual:
NitroQuickNitrostat
Sustained-release:
Nitro-Time
Topical:
Nitro-Bid
Transdermal:
DeponitMinitranNitrek, Nitro-Dur, NitrodiscTransderm-Nitro
Translingual:
Nitrolingual
Transmucosal:
Nitrogard

Pregnancy Category C

Drug classes
Antianginal
Nitrate

Therapeutic actions
Relaxes vascular smooth muscle with a resultant decrease in venous return and decrease in arterial BP, which reduces left ventricular workload and decreases myocardial oxygen consumption.

Indications
·        Sublingual, translingual preparations: Acute angina
·        Oral SR, sublingual, topical, transdermal, translingual, transmucosal preparations: Prophylaxis of angina
·        IV: Angina unresponsive to recommended doses of organic nitrates or beta-blockers
·        IV: Perioperative hypertension
·        IV: CHF associated with acute MI
·        IV: To produce controlled hypertension during surgery
·        Unlabeled uses: Reduction of cardiac workload in acute MI and in CHF (sublingual, topical); adjunctive treatment of Raynaud's disease (topical)

Contraindications and cautions
·        Contraindicated with allergy to nitrates, severe anemia, early MI, head trauma, cerebral hemorrhage, hypertrophic cardiomyopathy, pregnancy, lactation.
·        Use cautiously with hepatic or renal disease, hypotension or hypovolemia, increased intracranial pressure, constrictive pericarditis, pericardial tamponade, low ventricular filling pressure or low PCWP.

Available forms
Injection—0.5, 5 mg/mL; injection solution—25, 50, 100, 200 mg; sublingual tablets—0.3, 0.4, 0.6 mg; translingual spray—0.4 mg/spray; transmucosal tablets—1, 2, 3 mg; transmucosal SR tablets—1, 2, 2.5, 3, 5 mg; oral SR capsules—2.5, 6.5, 9 mg; transdermal—0.1, 0.2, 0.3, 0.4, 0.6, 0.8 mg/hr; topical ointment—2%

Dosages
ADULTS
IV
Initial dose, 5 mcg/min delivered through an infusion pump. Increase by 5-mcg/min increments every 3–5 min as needed. If no response at 20 mcg/min, increase increments to 10–20 mcg/min. Once a partial BP response is obtained, reduce dose and lengthen dosage intervals; continually monitor response and titrate carefully.
Sublingual
·        Acute attack: Dissolve 1 tablet under tongue or in buccal pouch at first sign of anginal attack; repeat every 5 min until relief is obtained. Do not take more than 3 tablets/15 min. If pain continues or increases, patient should call physician or go to hospital.
·        Prophylaxis: Use 5–10 min before activities that might precipitate an attack.
SR (oral)
Initial dose, 2.5–9 mg q 12 hr. Increase to q 8 hr as needed and tolerated. Doses as high as 26 mg given qid have been used.
Topical
Initial dose, one-half inch q 8 hr. Increase by one-half inch to achieve desired results. Usual dose is 1–2 inches q 8 hr; up to 4–5 inches q 4 hr have been used. 1 inch = 15 mg nitroglycerin.
Transdermal
Apply one patch each day. Adjust to higher doses by using patches that deliver more drug or by applying more than one patch. Apply patch to arm; remove hs.
Translingual
Spray preparation delivers 0.4 mg/metered dose. At onset of attack, spray one to two metered doses into oral mucosa; no more than three doses/15 min should be used. If pain persists, seek medical attention. May be used prophylactically 5–10 min prior to activity that might precipitate an attack.
Transmucosal
1 mg q 3–5 hr during waking hours. Place tablet between lip and gum above incisors, or between cheek and gum.
PEDIATRIC PATIENTS
Safety and efficacy not established.

Pharmacokinetics
Route
Onset
Duration
IV
1–2 min
3–5 min
Sublingual
1–3 min
30–60 min
Translingual spray
2 min
30–60 min
Transmucosal tablet
1–2 min
3–5 min
Oral, SR
20–45 min
8–12 hr
Topical ointment
30–60 min
4–8 hr
Transdermal
30–60 min
24 hr

Metabolism: Hepatic; T1/2: 1–4 min
Distribution: Crosses placenta; enters breast milk
Excretion: Urine

IV facts
Preparations: Dilute in 5% dextrose injection or 0.9% sodium chloride injection. Do not mix with other drugs; check the manufacturer's instructions carefully because products vary considerably in concentration and volume per vial. Use only with glass IV bottles and the administration sets provided. Protect from light and extremes of temperature.
Infusion: Do not give by IV push; regulate rate based on patient response.
Incompatibilities: Do not mix in solution with other drugs.

Adverse effects
·        CNS: Headache, apprehension, restlessness, weakness, vertigo, dizziness, faintness
·        CV: Tachycardia, retrosternal discomfort, palpitations, hypotension, syncope, collapse, orthostatic hypotension, angina
·        Dermatologic: Rash, exfoliative dermatitis, cutaneous vasodilation with flushing, pallor, perspiration, cold sweat, contact dermatitis—transdermalpreparations, topical allergic reactions—topical nitroglycerin ointment
·        GI: Nausea, vomiting, incontinence of urine and feces, abdominal pain
·        Local: Local burning sensation at the point of dissolution (sublingual)
·        Other: Ethanol intoxication with high-dose IV use (alcohol in diluent)

Interactions
·        Increased risk of hypertension and decreased antianginal effect with ergot alkaloids
·        Decreased pharmacologic effects of heparin
·        Risk of severe hypotension and adverse CV events with sildenafil, tadalafil, vardenafil; avoid this combination
·        False report of decreased serum cholesterol if done by the Zlatkis-Zak color reaction

Nursing considerations
CLINICAL ALERT!
Name confusion has occurred between NitroBid (nitrogylcerin) and Nicotral (nicotine); between nitroglycerin and nitroprusside; use caution.

Assessment
·        History: Allergy to nitrates, severe anemia, early MI, head trauma, cerebral hemorrhage, hypertrophic cardiomyopathy, hepatic or renal disease, hypotension or hypovolemia, increased intracranial pressure, constrictive pericarditis, pericardial tamponade, low ventricular filling pressure or low PCWP, pregnancy, lactation
·        Physical: Skin color, T, lesions; orientation, reflexes, affect; P, BP, orthostatic BP, baseline ECG, peripheral perfusion; R, adventitious sounds; liver evaluation, normal output; LFTs, renal function tests (IV); CBC, Hgb

Interventions
·        Give sublingual preparations under the tongue or in the buccal pouch. Encourage patient not to swallow. Ask patient if the tablet "fizzles" or burns. Always check the expiration date on the bottle; store at room temperature, protected from light. Discard unused drug 6 mo after bottle is opened (conventional tablets); stabilized tablets (Nitrostat) are less subject to loss of potency.
·        Give SR preparations with water; warn the patient not to chew the tablets or capsules; do not crush these preparations.
·        Administer topical ointment by applying the ointment over a 6 × 6 inch area in a thin, uniform layer using the applicator. Cover area with plastic wrap held in place by adhesive tape. Rotate sites of application to decrease the chance of inflammation and sensitization; close tube tightly when finished.
·        Administer transdermal systems to skin site free of hair and not subject to much movement. Shave areas that have a lot of hair. Do not apply to distal extremities. Change sites slightly to decrease the chance of local irritation and sensitization. Remove transdermal system before attempting defibrillation or cardioversion. Remove old system before applying a new one.
·        Administer transmucosal tablets by placing them between the lip and gum above the incisors or between the cheek and gum. Encourage patient not to swallow and not to chew the tablet.
·        Administer the translingual spray directly onto the oral mucosa; preparation is not to be inhaled.
·        WARNING: Arrange to withdraw drug gradually. 4–6 wk is the recommended withdrawal period for the transdermal preparations.

Teaching points
·        Place sublingual tablets under your tongue or in your cheek; do not chew or swallow the tablet; the tablet should burn or "fizzle" under the tongue. Take the nitroglycerin before chest pain begins, when you anticipate that your activities or situation may precipitate an attack. You may repeat your dose every 5 minutes for a total of three tablets. If the pain is not relieved, go to an emergency room. Do not buy large quantities; this drug does not store well. Keep the drug in a dark, dry place, in a dark-colored glass bottle with a tight lid; do not combine with other drugs.
·        Do not chew or crush the timed-release preparations; take on an empty stomach.
·        Spread a thin layer of topical ointment on the skin using the applicator. Do not rub or massage the area. Cover with plastic wrap held in place with adhesive tape. Wash your hands after application. Keep the tube tightly closed. Rotate the sites frequently to prevent local irritation.
·        To use transdermal systems, you may need to shave an area for application. Apply to a slightly different area each day. Remove the old system before you apply a new one. Use care if changing brands; each system has a different concentration.
·        Place transmucosal tablets between the lip and gum or between the gum and cheek. Do not chew; try not to swallow.
·        Spray translingual spray directly onto oral mucous membranes; do not inhale. Use 5–10 min before activities that you anticipate will precipitate an attack.
·        You may experience these side effects: Dizziness, light-headedness (may be transient; change positions slowly); headache (lie down in a cool environment and rest; over-the-counter preparations may not help); flushing of the neck or face (transient).
·        Report blurred vision, persistent or severe headache, rash, more frequent or more severe angina attacks, fainting.

Adverse effects in Italic are most common; those in Bold are life-threatening.

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