Side effects of varenicline

Like all medicines, varenicline can cause side effects, although not everyone gets them.

Common side effects of varenicline

Varenicline can have side effects, but there are things you can do to help cope with them.

If this advice does not help and any of these side effects bother you, talk to your doctor or pharmacist.

Serious side effects are rare but can happen.

Call a doctor or contact 111 now if you:

start to feel irritable, aggressive, anxious or experience changes to your heart rate (palpitations)

you have thoughts about harming yourself or ending your life
you have had a seizure or a fit
you get weakness on one side of your body, trouble speaking or thinking, loss of balance or blurred eyesight - these can be signs of a stroke
you get chest pain or shortness of breath - these may be signs 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.

In rare cases, it's possible to have a serious allergic reaction (anaphylaxis) to varenicline.

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.

These are not all the side effects of varenicline. For a full list see the leaflet inside your medicines packet.

You can report any suspected side effect using the Yellow Card safety scheme.