Like all medicines, isosorbide mononitrate and isosorbide dinitrate can cause side effects, although not everybody gets them. Side effects often improve as your body gets used to the medicine.
Common side effects of isosorbide mononitrate or isosorbide dinitrate
There are things you can do to help cope with these common side effects of isosorbide mononitrate or isosorbide dinitrate:
Headaches
Make sure you rest and drink plenty of water. Paracetamol is safe to take with isosorbide mononitrate and isosorbide dinitrate. Do not drink alcohol, as it could make your headaches worse.
Headaches usually go away after a few days. Talk to your doctor if they do not go away or are severe.
Feeling dizzy, weak, tired or sleepy
Stop what you're doing and sit or lie down until you feel better. Do not drink alcohol, as it could make you feel worse. Do not drive, ride a bike or use tools or machinery until you feel better.
Feeling sick (nausea)
Avoid rich, greasy or spicy foods, as these could make you feel worse. Stick to small, simple snacks or meals if you're hungry. It might help to take isosorbide mononitrate or isosorbide dinitrate after meals.
Flushing of the face
Try to cut down on coffee, tea and alcohol because they can make flushing worse. It might help to keep the room cool and use a fan. You could also spray your face with cool water or sip non-alcoholic cold or iced drinks.
Talk to your doctor or pharmacist if the advice on how to cope does not help and a side effect is still bothering you or does not go away.
Serious side effects
Serious side effects after taking isosorbide mononitrate or isosorbide dinitrate are rare.
Call a doctor or call 111 straight away if:
- your heart starts beating faster or slower than usual
- you get severe pain in your eye, headache, blurred vision or you suddenly lose sight in one eye – these could be signs of acute angle closure glaucoma
If you get chest pain and you've already been diagnosed with angina, follow the instructions you've been given for treating your angina:
- Stop what you're doing and rest.
- Use any medicine you've been prescribed – this is usually glyceryl trinitrate (GTN).
- Take another dose after 5 minutes if the first dose does not help.
- If you still have symptoms 5 minutes after taking the 2nd dose, call 999 for an ambulance.
Immediate action required: Call 999 now if:
- you have severe difficulty breathing
- you've fainted or passed out
- you get weakness in your arm or one side of your body or face, difficulty speaking or loss of co-ordination – these could be signs of a stroke
- your lips, tongue, face or skin suddenly turn blue or grey – on brown or black skin, this may be easier to see on the palms of the hands, soles of the feet, lips, gums and inside the eyelids
- you get chest pain that does not stop after a few minutes, and you may also feel sweaty, sick, light headed or short of breath – this could be a sign of a heart attack
Do not drive yourself to A&E.
The person you speak to at 999 will give you advice about what to do.
Serious allergic reaction
In rare cases, it's possible to have a serious allergic reaction (anaphylaxis) to isosorbide mononitrate or isosorbide dinitrate.
Immediate action required: Call 999 now if:
- your lips, mouth, throat or tongue suddenly become swollen
- you're breathing very fast or struggling to breathe (you may become very wheezy or feel like you're choking or gasping for air)
- your throat feels tight or you're struggling to swallow
- your skin, tongue or lips turn blue, grey or pale (if you have black or brown skin, this may be easier to see on the palms of your hands or soles of your feet)
- you suddenly become very confused, drowsy or dizzy
- someone faints and cannot be woken up
- a child is limp, floppy or not responding like they normally do (their head may fall to the side, backwards or forwards, or they may find it difficult to lift their head or focus on your face)
You or the person who's unwell may also have a rash that's swollen, raised, itchy, blistered or peeling.
These can be signs of a serious allergic reaction and may need immediate treatment in hospital.
Do not drive yourself to A&E.
The person you speak to at 999 will give you advice about what to do.
Other side effects
These are not all the side effects of isosorbide mononitrate and isosorbide dinitrate. For a full list, see the leaflet inside your medicines packet.
Reporting side effects
You can report any suspected side effect using the Yellow Card safety scheme.
Visit the Yellow Card website for more information about reporting side effects.