Nitroglycerin-topical

Other drugs may interact with nitroglycerin topical, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.

Administration

Rectal Administration

0.4% ointment: apply rectally into the anal canal; do not administer orally, vaginally, or topically to the eye.1

Apply using a finger covering (e.g., plastic wrap, disposable surgical glove, finger cot).1 Squeeze a line of ointment equaling the length of the measuring line on the dosage guide on the ointment carton onto the covered finger.1

Gently insert ointment into the anal canal no further than to the first finger joint using the covered finger; also apply around the side of the anal canal.1 If pain prevents insertion, apply directly to the outside of the anus.1

Discard the used finger covering and wash hands after application of the ointment.1

Dosage

Adults

375 mg (1 inch) of 0.4% ointment (equivalent to 1.5 mg nitroglycerin) every 12 hours for ≤3 weeks.1

Improved outcomes (e.g., healing rates, reduction in pain) reported after extension of treatment duration to 6 weeks†.3 5 6

Special Populations

No special population dosage recommendations at this time.1

Contraindications

• Known hypersensitivity to nitroglycerin, other nitrates or nitrites, or any ingredient in the formulation.1

• Concomitant or recent (within a few days) treatment with selective phosphodiesterase type 5 (PDE5) inhibitors (e.g., sildenafil, tadalafil, vardenafil).1

• Severe anemia or increased intracranial pressure.1

Warnings/Precautions

Sensitivity Reactions

Flushing, allergic reactions, and application site reactions (including drug rash and exfoliative dermatitis) reported rarely.1

Cardiovascular Effects

May cause venous and arterial dilation, which can decrease venous blood returning to the heart and reduce arterial vascular resistance and systolic pressure.1

Use with caution in patients with blood volume depletion, hypotension, cardiomyopathies, CHF, acute MI, or poor cardiac function; monitor cardiovascular status and clinical condition in such patients.1

More pronounced adverse cardiovascular effects likely in geriatric patients.1

Risk of transient lightheadedness, occasionally related to BP changes.1 Hypotension (including orthostatic hypotension), in some cases requiring discontinuance of nitroglycerin ointment, reported infrequently.1

Headache

Risk of dose-related headaches, which may be severe; headaches typically are of short duration and respond to analgesics (e.g., acetaminophen).1 8 Tolerance occurs but headache may recur after each dose.1 8 Prophylactic acetaminophen recommended by some clinicians.3

Specific Populations

Category C.1

Not known whether nitroglycerin is distributed into milk.1 Caution if used in nursing women.1

Safety and efficacy not established in pediatric patients <18 years of age.1

Insufficient experience in patients ≥65 years of age to determine whether geriatric patients respond differently than younger adults.1

Increased sensitivity to nitrates (e.g., more frequent or severe hypotension and related dizziness or fainting) reported in geriatric patients; may be related to higher frequency of decreased hepatic, renal, and/or cardiac function and of concomitant disease and drug therapy.1

Common Adverse Effects

Headache,1 6 7 dizziness.1 6

• Principal pharmacologic property is relaxation of vascular smooth muscle, resulting in generalized vasodilation.1

• Nitroglycerin forms free radical nitric oxide, which activates guanylate cyclase; activation of guanylate cyclase results in an increase of guanosine-3′,5′-monophosphate (cyclic GMP) in smooth muscle and other tissues, leading to dephosphorylation of myosin light chains and vasodilation.1

• Intra-anal application of nitroglycerin reduces sphincter tone and resting intra-anal pressure.1 4 5 7 The reduction in anal pressure may result in increased anal blood flow.4 7