Nitroglycerin

Indications

Angina Pectoris

Nitrofix SR is used to relieve an angina (chest pain) attack as it happens and to help prevent future attacks caused by coronary artery disease.

⚠️ Always consult a registered physician before taking any medicine.

Pharmacology

The main way nitroglycerin works is by relaxing the smooth muscle in blood vessels. It widens both arteries and veins, though the effect is stronger on the veins. When the small veins after the capillaries widen, more blood collects in the limbs and other parts of the body, so less blood returns to the heart. This lowers the left ventricular end-diastolic pressure, which is known as preload. Relaxation of the arterioles lowers systemic vascular resistance and arterial pressure, which is the afterload.

Nitroglycerin releases free radical nitric oxide (NO). This activates guanylate cyclase, which raises the level of cyclic GMP (guanosine 3',5'-monophosphate) in smooth muscle and other tissues. Over time this causes dephosphorylation of myosin light chains. These chains control how tightly smooth muscle contracts, so the result is vasodilation.

Absorption: Nitroglycerin is absorbed quickly, which is why it is so often used in emergencies.

Distribution: The volume of distribution of nitroglycerin is 3 L/kg.

Metabolism: The liver breaks nitroglycerin down quickly, using its enzymes, into di-nitrates and mononitrates.

Elimination: The kidneys remove nitroglycerin from the body, mainly as its 2 di-nitro metabolites.

Pregnancy & Breastfeeding

Pregnancy & Breastfeeding: The safety of nitrates during pregnancy and breastfeeding has not been established, as there is no clear evidence to confirm it. For this reason, doctors should only prescribe nitrates to pregnant women or nursing mothers when they judge it truly necessary. It is also not known whether Nitroglycerin passes into breast milk.

⚠️ Talk to your doctor before taking any medicine during pregnancy or while breastfeeding.

Dosage Reference

⚠️ Reference ranges from official sources only. Consult your doctor for personalized dosing.

Adults: Sublingual tablet: One tablet (0.5 mg) should be dissolved under the tongue as soon as an acute anginal attack begins. The dose may be repeated about every five minutes until relief is obtained. If pain continues after a total of 3 tablets taken within 15 minutes, prompt medical attention is recommended. Sustained release tablet: The dose should always be adjusted according to the individual patient's requirement, response and the severity of the anginal pain. 2.6 mg: 1 tablet 2 times a day before meals, in the morning and at noon. If necessary, the dose may be raised gradually to 2 or 3 tablets twice daily. 6.4 mg: One tablet twice daily, or as directed by the registered physician. Spray: At the onset of an attack, one metered dose spray or two metered dose sprays should be given under the tongue. A spray may be repeated about every 5 minutes as needed, up to a maximum of 3 metered sprays within a 15 minute period. If chest pain continues after a total of 3 sprays, prompt medical attention is recommended. It may also be used beforehand, 5 to 10 minutes ahead of activities that might bring on an acute attack.

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Indications

Pharmacology

Pregnancy & Breastfeeding

Dosage Reference

Side Effects & Interactions

Side Effects

Key Interactions