Diazepam Side Effects
Common Side Effects
Like all medicines, diazepam can also cause side effects, although not everyone gets them. Many of these are related to its effect on the brain and central nervous system. Some side effects are more common and are more noticeable at the starting of the treatment or when the dose is increased. These may improve with time as your body adjusts to the medicine.
Drowsiness
Drowsiness or sleepiness is one of the most common diazepam side effects. You may experience:
- Feeling more sleepy than usual
- Reduced level of alertness
- Slower reaction times
Excessive sleepiness can interfere your ability to drive or operate heavy machinery. Hence, you should refrain from doing so. It is more likely to happen at higher doses or when it is taken with other medicines that have the same effect.
Dizziness
You may feel dizzy, particularly when you stand up quickly. This can cause:
- A feeling of light headedness
- Make you feel unsteady
- An increase in the risk of falls
This effect may be more pronounced in older adults. Due to this reason careful dosing and monitoring are essential.
Other common effects
Apart from the effects explained above, some people may also experience:
- Tiredness
- Weakness in the muscles
- Impaired coordination
These effects are typically mild and may improve as your body starts adjusting to the medicine.
Less Common Effects
These are certain side effects which are less common but can still occur and can vary depending on how your body responds to the medicine. These can be:
- Difficulty in concentration
- Confusion
- Memory problems
- Mood changes
- Blurring of vision
- Nausea
In some cases, the effects can be opposite of what is expected, such as
- Feeling agitated or unsettled
- Irritability
- Restlessness
If you notice these changes, you may need to consult a qualified healthcare professional, as your treatment may need to be adjusted.
Serious Side Effects
Some side effects are less common, but can happen and can be more serious.
Breathing problems
In certain situations, diazepam may slow down breathing. This is more likely to happen at higher doses or if it is taken with other medicines that cause sedation. This risk may increase if:
- You are taking opioids or sleeping tablets
- You have underlying breathing conditions
- Alcohol is consumed
If any of the above stands true, you should watch for the following symptoms:
- Slow or shallow breathing
- Severe drowsiness
- Difficulty staying awake
Dependence and misuse
With longer use or higher doses, there is a risk that you may become dependent on diazepam. This can involve both physical and psychological dependence along with a difficulty stopping the medicine.
For these reasons diazepam is prescribed under ongoing medical supervision and is reviewed at intervals.
Severe reactions
Serious reactions are less common, almost rare, but can occur. These may include:
- Severe confusion
- Unusual changes in behaviour
- Allergic reactions such as swelling of the face or throat
You must seek urgent medical help if you happen to experience any of these.
Long-Term Risks
Taking diazepam for a prolonged period can increase the risk of some complications.
Tolerance
With time, the body may become less responsive to the same dose. This means:
- Higher doses may be needed to achieve the same effect
- Effectiveness may reduce over time
Dependence and withdrawal
- Long-term use of diazepam may lead to dependence
- If you stop taking the medicine suddenly, you may experience withdrawal symptoms. This includes, anxiety, restlessness, or sleep disturbance
- In cases where dose reduction is required, it should always be gradual
Cognitive and physical effects
Prolonged use may affect memory, concentration, or coordination. This can impact daily functioning, especially in older adults.
When to Seek Medical Help
You should know when to seek urgent medical help. It is important to keep taking diazepam safely. The conditions include:
- Continuous drowsiness that affects daily activities
- Persistent confusion or memory problems
- Unusual behaviour or mood changes
Seek urgent medical care if there is:
- Slow or difficult breathing
- Severe drowsiness or inability to stay awake
- Loss of consciousness
- Signs of an allergic reaction (swelling, rash, or difficulty breathing)
General safety advice
To reduce risks:
- Take it exactly as it is prescribed
- Avoid taking any extra doses
- Not share your medicine with others even if they are dealing with same problem
Is Diazepam Safe?
Diazepam can be safe and helpful when used in the right way under medical supervision. Like any medicine, it also has risks particularly when used for long or at incorrect doses.
Getting to know about diazepam side effects, following medical advice, and noticing warning signs, can make its use safer.
Disclaimer
This information is based on the UK clinical guidelines and patient information leaflets and is to give a general understanding and what you might expect while taking it.
This content does not replace any medical advice, diagnosis, or treatment. If you have any concerns about your health, please seek advice from a licenced and qualified healthcare professional.
References:
- Electronic Medicines Compendium, Diazepam Patient Information Leaflet, https://www.medicines.org.uk/emc/files/pil.101911.pdf [accessed 30 April 2026].
- National Health Service, Side Effects of Diazepam, https://www.nhs.uk/medicines/diazepam/side-effects-of-diazepam/ [accessed 30 April 2026].
- National Health Service, About Diazepam, https://www.nhs.uk/medicines/diazepam/about-diazepam/ [accessed 30 April 2026].
- National Health Service, Taking Diazepam with Other Medicines and Herbal Supplements, https://www.nhs.uk/medicines/diazepam/taking-diazepam-with-other-medicines-and-herbal-supplements/ [accessed 30 April 2026].
- National Health Service, Pregnancy, Breastfeeding and Fertility while Taking Diazepam, https://www.nhs.uk/medicines/diazepam/pregnancy-breastfeeding-and-fertility-while-taking-diazepam/ [accessed 30 April 2026].
- British National Formulary, Diazepam, https://bnf.nice.org.uk/drugs/diazepam/ [accessed 30 April 2026].