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Nitrates


What do Nitrates do?

How do I take them?

Side effects

What do Nitrates do?

Nitrates are used to relieve angina and they can also be used to prevent angina.  Nitrates come as tablets, capsules, patches and sprays.  Common types are glyceryl trinitrate (GTN), isosorbide mononitrate and isosorbide dinitrate.  There are many different brands, but each brand contains one of these three medicines.

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How do I take them?

GTN tablets and sprays (quick acting nitrates)

  • If you know certain activities can bring on your angina (e.g. walking uphill, carrying shopping,  making love), use a dose of GTN a few minutes before to prevent the chest pain coming on.  The effects should last about one hour.  If you need to take your GTN before certain activities, let your doctor or nurse know next time you see them.  They may be able to adjust your regular medicines to stop your angina coming on. 

  • Taking away angina once you have got it:
    If you have chest pains try to sit down and use one or two puffs of your spray under the tongue, if you prefer you can use one of the GTN tablets under the tongue.  If the pain hasn't gone within five minutes use your spray again or take another tablet.  If the pain is still there after a further five minute use your spray or take another tablet for a third time.  If the chest pain is still there after a third dose, phone an ambulance and your doctor.  Do not hesitate to phone an ambulance as you may be experiencing a heart attack.

    Do not take more than three doses (3 to 6 puffs or tablets) in fifteen minutes.
  • Bottles of GTN tablets only last for eight weeks once the bottle is opened.  If your bottle has been open for eight weeks or it is past the expiry/use by date discard it and get a new supply. Once expired the tablets will not work to relieve your angina.  Sprays last much longer but you should always get a new spray before the old one is empty or it passes its expiry/use by date. Carry a spray (or your tablet bottle) with you when you go out so they are always handy if you need them.

Isosorbide mononitrate or dinitrate (long acting nitrates)

  • You should take these medications at the same time everyday and you should swallow them whole with a glass of water.  They will not work properly if you take them at the wrong time of day so check with your doctor or pharmacist. You should take them as prescribed by your doctor. If you take these tablets twice a day they should normally be taken in the morning and early afternoon (for example 8am and 2pm).

  • If you need to, you can use your GTN spray or GNT tablets even if you are taking isosorbide mononitrate or dinitrate.

GTN patches

  • This medicine is taken into the blood across the skin. The patch must be removed at bedtime and a new patch put on the next morning. 

  • Occasionally, if your angina is troublesome at night, the patch will be put on in the evening and taken off in the morning.  However you use them, you must have some time (ideally an 8 hour period), during the 24 hours when you don't have the patch on.  The medicine is not effective if you don't have a gap.

  • Patches should only be used if you cannot swallow tablets. If the patch makes your skin a bit red or itchy you should alternate where you place it each day.  The patch is best placed on the front of your chest or the upper arm.  The patch can be kept on while showering or bathing.  If you need to you can use your GTN spray or tablets while you have a patch on.

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Side effects

All nitrates can cause headaches, dizziness and flushing of the face, usually soon after starting treatment.  If you are dizzy or light headed, you should try to lie down as this may help.  Most of these symptoms reduce with continued use and are rarely troublesome.

If you think you have any side effects from this medicine be sure to mention them to your GP, practice nurse or pharmacist. 

Do not take Viagra (sildenafil), Cialis (Tadalafil) or Levitra (Vardenafil) whilst taking this medicine because it could cause your blood pressure to drop to a dangerously low level.

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