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Side effects of diazepam

Like all medicines, diazepam can cause side effects in some people, but many people have no side effects or only minor ones.

Common side effects

These common side effects of diazepam happen in more than 1 in 100 people. There are things you can do to help cope with them:

Feeling sleepy or drowsy

Do not drive, cycle or use tools or machinery until you feel better. Do not drink any alcohol. This side effect should get better as your body gets used to the medicine. If your symptoms do not improve after a week, speak to a doctor as you may need a lower dose.


Keep taking the medicine and speak to your doctor.

Problems with your co-ordination or controlling your movements

Keep taking the medicine and speak to your doctor.

Shaky hands (tremors)

Keep taking the medicine and speak to your doctor.

Serious side effects

It happens rarely, but some people have serious side effects when taking diazepam.

Call a doctor or call 111 now if:

  • your skin turns yellow, or the whites of your eyes turn yellow although this may be less obvious on brown or black skin
  • you see or hear things that are not there (hallucinations)
  • you think things that are not true (delusions)
  • you keep falling over
  • you have unusual mood changes such as talking more than usual or feeling overexcited, agitated, restless, irritable or aggressive – these side effects are more likely in children or if you're over 65

Make an appointment to see your doctor if you have memory loss (amnesia).

Immediate action required: Call 999 or go to A&E now if:

  • your breathing becomes very slow or shallow

Find your nearest A&E

Serious allergic reaction

In rare cases, diazepam may cause a serious allergic reaction (anaphylaxis).

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.

Long-term side effects

Diazepam can cause withdrawal symptoms if you take it for a long time.

If you're prescribed diazepam for more than 4 weeks, your dose may be reduced gradually when you stop taking it to prevent withdrawal symptoms.

Other side effects

These are not all the side effects of diazepam. For a full list, see the leaflet inside your medicine packet.


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

Visit Yellow Card for further information.

Page last reviewed: 3 February 2022
Next review due: 3 February 2025