Sleeping tablets work, which is precisely why they need care. They shorten the time taken to fall asleep and are genuinely useful for a short period. They are not designed for months of use, and the difficulties come almost entirely from that gap between how they are intended to be used and how they often end up being used.
Three groups are commonly used: Z-drugs such as zolpidem and zopiclone, benzodiazepines, and sedating antihistamines sold over the counter. They differ in detail but share most of what follows.
Common side effects and early adjustment effects
- Drowsiness carrying into the next morning, and a hungover feeling
- Dizziness and unsteadiness, particularly getting up during the night
- Headache
- Dry mouth, and a bitter taste with zopiclone in particular
- Memory gaps around the time of the dose
- Reduced concentration the following day
Next-day impairment is the effect most often underestimated. Reaction time and judgement can still be affected in the morning even when you feel awake, which is directly relevant to driving and to work involving machinery. Take one only when a full night of sleep is possible. See next-day drowsiness.
Serious mood, behaviour or physical symptoms to take seriously
Combining sleeping tablets with alcohol or opioid painkillers can dangerously slow breathing. Get emergency help for very slow or shallow breathing, extreme drowsiness, or someone who cannot be roused. See sleeping tablets and alcohol.
Complex sleep behaviours. Some people carry out activities while not fully awake with no memory afterwards: walking, eating, phoning, occasionally driving. Uncommon but serious, and far more likely with alcohol or higher than prescribed doses. If it happens even once, contact your prescriber promptly rather than continuing.
Also report: confusion or hallucinations; agitation or aggression, which occasionally occurs instead of sedation and is more common in children and older adults; new or worsening low mood or thoughts of self-harm; or a fall.
Older adults are more sensitive to all of these and face a higher risk of falls, fractures and confusion. See medicine side effects in older adults.
Sexual, sleep, weight and emotional side effects
Tolerance and dependence. With regular use the effect tends to lessen while the body adapts to the medicine being present. This is why these are intended for short courses, and why a prescription meant for two weeks becoming a standing repeat is worth reviewing rather than continuing by default. Dependence does not require misuse; it develops from taking the medicine as prescribed.
Rebound insomnia is the trap. When you stop, sleep is briefly worse than before the tablets started. It usually settles within days, but it reads convincingly as proof that you still need them, and that impression is what turns a short course into a long one.
Sleeping tablets also change sleep rather than restore it, and they do not treat whatever is disrupting it. If insomnia has lasted more than a few weeks, ask about approaches that address the cause, which work better over time than continued medication.
Interactions, alcohol, pregnancy and other risk factors
- Alcohol. Substantially increases sedation and is the main factor in complex sleep behaviours. Do not combine.
- Opioid painkillers. The most dangerous combination.
- Other sedating medicines, including antihistamines, some antidepressants and antipsychotics.
- Sleep apnoea or breathing problems, which make sedatives riskier. Tell your prescriber if you snore heavily or stop breathing in your sleep.
- Pregnancy and breastfeeding. Generally avoided; seek advice.
What to ask your doctor before changing dose or stopping
After regular use, stopping suddenly can cause rebound insomnia, anxiety, agitation and tremor, and after prolonged benzodiazepine use withdrawal can be severe. Reduce gradually with your prescriber. See sleeping pill withdrawal symptoms.
- How many nights should I take this, and when do we review?
- If I have been on it a while, how do we reduce it?
- Am I safe to drive the next morning?
- What else am I taking that adds to the sedation?
- What non-medicine options are there for my insomnia?
Related mental health medication guides
- Sleep medication side effects
- Zolpidem and zopiclone
- Benzodiazepine side effects
- Mental health medication side effects
- Report a side effect in South Africa
Medical Disclaimer: This content is for informational and educational purposes only and does not constitute medical diagnosis, prescription, or professional advice. Always read the patient information leaflet and consult a qualified doctor or pharmacist regarding any medicine or health concern.