Nitrate vasodilator (heart medicine)
Last reviewed June 2026
Who is this for?
Glyceryl trinitrate (also called GTN or nitroglycerin) is a heart medicine that works by relaxing and widening your blood vessels, which improves blood flow to the heart and reduces the heart's workload.
Activates guanylate cyclase via nitric oxide release in vascular smooth muscle, increasing cyclic GMP levels and causing vasodilation of coronary and peripheral blood vessels, thereby reducing cardiac preload and myocardial oxygen demand.
Prescription Required
You need a doctor's prescription to buy this drug.
Explore this drug
This drug comes in different forms. For the tablet placed under the tongue (sublingual): place 1 tablet (0.3mg to 0.6mg) under your tongue when you feel chest pain — do not swallow it, let it dissolve. You can repeat after 5 minutes if pain continues, up to 3 tablets in 15 minutes. For the sustained-release tablet like Nitrocontin 6.4: swallow 1 tablet (6.4mg) two to three times daily — do not crush or chew it. Your doctor will decide the right dose for you.
If you are taking the regular long-acting tablets and you miss a dose, take it as soon as you remember. But if it is almost time for your next dose, skip the missed one — do not take double. For the under-the-tongue type, you only use it when you have chest pain, so there is no 'missed dose.'
Always get this medicine from a licensed pharmacy — buying heart medicines from roadside sellers or unregistered shops is very dangerous as fake or expired products are common. If your under-the-tongue tablet does not relieve chest pain after 3 doses in 15 minutes, rush to the nearest hospital immediately. Do not stop taking the long-acting form suddenly without your doctor's advice, as this can worsen your condition.
Do NOT take with Sildenafil (Viagra) or similar drugs for erection problems — the combination can cause a dangerous drop in blood pressure that can be life-threatening. Avoid alcohol as it can worsen dizziness and cause your blood pressure to drop dangerously low. Blood pressure medications may increase the blood pressure-lowering effect, so your doctor needs to know about all medicines you are taking.
Check your specific combination
Is it safe to take Glyceryl with your other drugs?
This drug is not recommended during pregnancy or breastfeeding unless your doctor specifically says the benefit outweighs the risk — always consult your doctor.
Store in a cool, dry place away from direct sunlight and heat — this is very important in Nigeria's hot weather as heat can make this drug lose its effectiveness. Keep the tablets in their original container, tightly closed. Keep far away from children. Do not store in the bathroom or kitchen where there is moisture.
For information only — not medical advice. Always talk to a doctor or pharmacist before changing your medication.
Names this drug is sold under — especially in Nigerian and West African pharmacies
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Counterfeit Drug Warning
Fake drugs are a serious problem in Nigeria. Always buy from a registered pharmacy. If the packaging looks different from what is described above, do not use it.