Nitroglycerin (6.4mg) is a long-acting nitrate formulation, primarily available as a transdermal patch or an extended-release tablet in the Indian market. It is a prodrug that releases nitric oxide (NO), a potent vasodilator. It is a cornerstone in the prophylactic management of chronic stable angina pectoris by reducing myocardial oxygen demand and improving coronary blood flow. The 6.4mg strength typically refers to the total drug content in a transdermal patch designed for 24-hour delivery, releasing approximately 0.2-0.4 mg/hour.
Adult: Transdermal Patch (6.4mg/24h): Apply ONE patch daily to a clean, dry, hairless area of skin on the chest, back, or upper arm. Rotate sites to avoid skin irritation. For angina prophylaxis, apply in the morning and remove after 12-14 hours to provide a nitrate-free interval. Maximum: One 6.4mg/24h patch per day.
Note: Apply patch to intact, non-hairy, non-irritated skin. Press firmly in place. Do not cut the patch. Wash hands after application. Remove old patch before applying new one. Avoid areas with cuts or irritation. Do not apply heat over the patch.
Nitroglycerin is a prodrug that undergoes enzymatic conversion (primarily in vascular smooth muscle cells) to release nitric oxide (NO). NO activates soluble guanylyl cyclase, increasing intracellular cyclic guanosine monophosphate (cGMP). Elevated cGMP leads to dephosphorylation of myosin light chains, resulting in smooth muscle relaxation, vasodilation, and inhibition of platelet aggregation.
Pregnancy: Category C (US FDA). Animal studies show risk, human data inadequate. Use only if potential benefit justifies potential fetal risk. Not recommended during pregnancy unless absolutely necessary for maternal health.
Driving: May cause dizziness, lightheadedness, or syncope, especially at initiation or dose increase. Patients should not drive or operate machinery until their individual response is known.
| Phosphodiesterase-5 Inhibitors (Sildenafil, Tadalafil, Vardenafil) | Profound, life-threatening hypotension | Contraindicated |
| Other Vasodilators (ACE inhibitors, ARBs, Calcium channel blockers, Alpha-blockers) | Additive hypotensive effect | Major |
| Antihypertensives | Enhanced blood pressure lowering | Major |
| Heparin | Possible decreased anticoagulant effect of heparin | Moderate |
| Alcohol | Enhanced vasodilation and hypotension | Major |
| Dihydroergotamine | May reduce anti-anginal effect of nitrates; may increase ergot toxicity | Moderate |
| Aspirin | Increased nitrate bioavailability (theoretical) | Minor |
Same composition (Nitroglycerin (6.4mg)), different brands: