nitroglycerin (glyceryl trinitrate)
Anginine‡, Deponit, Minitran, Nitradisc‡, Nitro-Bid, Nitro-Bid IV, Nitrocine, Nitrodisc, Nitro-Dur, Nitrogard, Nitrogard SR†, Nitroglyn, Nitrol, Nitrolingual, Nitrong, Nitrostat, Nitro-Time, NTS, Transderm-Nitro, Transiderm-Nitro‡, Tridil
Pregnancy Risk Category C
How supplied
Tablets (buccal): 1 mg, 2 mg, 3 mg
Tablets (S.L.): 0.15 mg (1/400 gr), 0.3 mg (1/200 gr), 0.4 mg (1/150 gr), 0.6 mg (1/100 gr)
Tablets (sustained-release): 2.6 mg, 6.5 mg, 9 mg, 13 mg
Capsules (sustained-release): 2.5 mg, 6.5 mg, 9 mg, 13 mg
Aerosol (translingual): 0.4 mg metered spray
Topical: 2% ointment
Transdermal: 0.1 mg, 0.2 mg, 0.3 mg, 0.4 mg, 0.6 mg, 0.8 mg per hour release rate
Injection: 0.5 mg/ml, 5 mg/ml
Action
A nitrate that reduces cardiac oxygen demand by decreasing left ventricular end-diastolic pressure (preload) and, to a lesser extent, systemic vascular resistance (afterload). Also increases blood flow through the collateral coronary vessels.
Indications & dosage
Prophylaxis against chronic anginal attacks--
Adults: 2.5 or 2.6 mg sustained-release capsule or tablet q 8 to 12 hours, adjusted upward to an effective dose in 2.5- or 2.6-mg increments b.i.d. to q.i.d. Or, use 2% ointment: Start dosage with 1/2-inch ointment, increasing by 1/2-inch increments until desired results are achieved. Range of dosage with ointment is 1/2 to 5 inches. Usual dose is 1 to 2 inches. Or, transdermal disc or pad (Nitrodisc, Nitro-Dur, or Transderm-Nitro) 0.2 to 0.4 mg/hour once daily.
Acute angina pectoris, prophylaxis to prevent or minimize anginal attacks before stressful events--
Adults: 1 S.L. tablet (gr 1/400, 1/200, 1/150, 1/100) dissolved under the tongue or in the buccal pouch as soon as angina begins. Repeat q 5 minutes, if needed, for 15 minutes. Or, using Nitrolingual spray, one or two sprays into mouth, preferably onto or under the tongue. Repeat q 3 to 5 minutes, if needed, to a maximum of three doses within a 15-minute period. Or, 1 to 3 mg transmucosally q 3 to 5 hours during waking hours.
Hypertension associated with surgery, heart failure associated with MI, angina pectoris in acute situations, to produce controlled hypotension during surgery (by I.V. infusion)--
Adults: initial infusion rate is 5 mcg/
minute, increased p.r.n. by 5 mcg/minute q 3 to 5 minutes until response occurs. If a 20 mcg/minute rate doesn't produce a response, may increase dosage by as much as 20 mcg/minute q 3 to 5 minutes. Up to 100 mcg/minute may be needed.
Adverse reactions
CNS: headache, dizziness, weakness.
CV: orthostatic hypotension, tachycardia, flushing, palpitations, fainting.
GI: nausea, vomiting.
Skin: cutaneous vasodilation, contact dermatitis (patch), rash.
Other: hypersensitivity reactions, sublingual burning.
Interactions
Drug-drug. Antihypertensives: possible enhanced hypotensive effect. Monitor closely.
Heparin: I.V. nitroglycerin interferes with anticoagulant effect of heparin in some patients. Monitor PTT.
Sildenafil: may increase risk of hypotension. Avoid concomitant use.
Drug-lifestyle. Alcohol use: possible increased hypotension. Avoid alcohol intake.
Effects on diagnostic tests
Nitroglycerin may interfere with serum cholesterol determination tests using the Zlatkis-Zak color reaction, resulting in falsely decreased values.
Contraindications
Contraindicated in patients with early MI, severe anemia, increased intracranial pressure, angle-closure glaucoma, orthostatic hypotension, allergy to adhesives (transdermal), or hypersensitivity to nitrates. I.V. nitroglycerin is contraindicated in patients with hypersensitivity to I.V. form, cardiac tamponade, restrictive cardiomyopathy, or constrictive pericarditis.
Nursing considerations
- Use cautiously in patients with hypotension or volume depletion.
- Closely monitor vital signs during infusion. Be particularly aware of blood pressure, especially in a patient with an MI. Excessive hypotension may worsen the MI.
- To apply ointment, measure the prescribed amount on the application paper; then place the paper on any nonhairy area. Don't rub in. Cover with plastic film to aid absorption and to protect clothing. Remove all excess ointment from previous site before applying the next dose. Avoid getting ointment on fingers.
- Transdermal dosage forms can be applied to any nonhairy part of the skin except distal parts of the arms or legs (absorption won't be maximal at distal sites).
- Remove transdermal patch before defibrillation. Because of the aluminum backing on the patch, the electric current may cause arcing that can result in damage to paddles and burns to the patient.
- When stopping transdermal treatment of angina, gradually reduce the dose and frequency of application over 4 to 6 weeks, as ordered.
- Monitor blood pressure and intensity and duration of drug response.
- Drug may cause headaches, especially at beginning of therapy. Dosage may be reduced temporarily, but tolerance usually develops. Treat headache with aspirin or acetaminophen.
- Tolerance to drug can be minimized with a 10- to 12-hour nitrate-free interval. To achieve this, remove the transdermal system in the early evening and apply a new system the next morning or omit the last daily dose of a buccal, sustained-release, or ointment form. Check with the doctor for alterations in dosage regimen if tolerance is suspected.
- Alert:
Don't confuse Nitro-Bid with Nicobid or nitroglycerin with nitroprusside.
I.V. administration
- Dilute with D5W or normal saline for injection. Concentration shouldn't exceed 400 mcg/ml. Always administer with an infusion control device and titrate to desired response. Also, always mix in glass bottles and avoid use of I.V. filters because drug binds to plastic. Regular polyvinyl chloride tubing can bind up to 80% of drug, making it necessary to infuse higher dosages. A special nonabsorbent polyvinyl chloride tubing is available from the manufacturer; patients receive more drug when these infusion sets are used. Always use the same type of infusion set when changing I.V. lines.
- When changing the concentration of infusion, flush the I.V. administration set with 15 to 20 ml of the new concentration before use. This will clear the line of the old drug solution.
Patient teaching
- Caution patient to take nitroglycerin regularly, as prescribed, and to have it accessible at all times.
- Alert:
Advise patient that abrupt discontinuation of drug causes coronary vasospasms.
- Teach patient how to administer the prescribed form of nitroglycerin.
- Tell patient to take S.L. tablet at first sign of attack. The tablet should be wet with saliva and placed under the tongue until absorbed, and the patient should sit down and rest. Dose may be repeated every 5 minutes for a maximum of three doses. If drug doesn't provide relief, medical help should be obtained promptly.
- Advise patient who complains of a tingling sensation with S.L. drug to try holding tablet in buccal pouch.
- Tell patient to take oral tablets on an empty stomach either 30 minutes before or 1 to 2 hours after meals, to swallow oral tablets whole, and not to chew tablets.
- Remind patient using translingual aerosol form that he shouldn't inhale the spray, but should release it onto or under the tongue. Also tell him to wait about 10 seconds or so before swallowing.
- Tell patient to place the buccal tablet between the lip and gum above the incisors or between the cheek and gum. Tablets shouldn't be swallowed or chewed.
- Tell patient to take an additional dose before anticipated stress or at bedtime if angina is nocturnal.
- Instruct patient wearing transdermal patch to use caution when near a microwave oven. Leaking radiation may heat patch's metallic backing and cause burns.
- Advise patient to avoid alcohol.
- To minimize orthostatic hypotension, tell patient to change to upright position slowly. Advise him to go up and down stairs carefully and to lie down at the first sign of dizziness.
- Tell patient to store drug in cool, dark place in a tightly closed container. Remove cotton from container because it absorbs drug.
- Tell patient to store S.L. tablets in original container or other container specifically approved for this use and to carry the container in a jacket pocket or purse, not in a pocket close to the body.
*Liquid contains alcohol. **May contain tartrazine. †Canada ‡Australia §U.K. OTCOver the counter
Reactions may be common, uncommon, life-threatening, or COMMON AND LIFE-THREATENING