Side effect

What happens

What to do about it

COMMON (more than about 1 in 10 people might get these)

Sleepiness

You feel sleepy, drowsy or sluggish. It can last for a few hours after taking your dose, or longer.

Don't drive or use machinery.
Discuss with your doctor if you can take the drug at a different time of the day.

Dizziness

Feeling light-headed and faint.

Don't stand up too quickly. Try and lie or sit down if you feel it coming on. Don't drive.

Headache

Your head is pounding and painful.

Try paracetamol. Your pharmacist will be able to advise if this is safe to take with any other medicines you may be taking.

Skin rashes

Red rashes across the face and body, blisters and inflammation in the nose, mouth and eyes. It may look a bit like serious burning or sunburn.

Stop taking and contact your doctor straight away. This can be dangerous as it might be the start of the rare Stevens-Johnson syndrome. 

Nausea

Feeling sick.

If it is bad, contact your doctor.

UNCOMMON (less than about 1 in 10 people might get these)

Oedema

Swelling in the legs, face, lips or tongue.

Call your doctor now.

Blurred vision

Things look fuzzy and you can't focus properly.

Don't drive. See your doctor if you are worried. You won't need glasses.

RARE (less than about 1 in 100 people might get these)

Bone marrow suppression

Unexpected bruising, infections, and anaemia

Stop taking and contact your doctor straight away.

Seizures

Having a fit or convulsion, or a worsening of your symptoms.

Stop taking and contact your doctor straight away.