How does it work?
Sonata capsules contain the active ingredient zaleplon, which is a type of medicine called a non-benzodiazepine hypnotic. It acts in the brain to aid sleep.
Zaleplon works by acting specifically on receptors in the brain called GABA-A receptors. This causes the release of a neurotransmitter called GABA in the brain.
GABA is a neurotransmitter that acts as a natural 'nerve-calming' agent. It helps keep the nerve activity in the brain in balance, and is involved in inducing sleepiness, reducing anxiety and relaxing muscles.
Zaleplon can be used as a short-term treatment for insomnia in people who are having difficulty falling asleep that is causing them severe distress.
Zaleplon decreases the time taken to fall asleep and increases the total amount of time spent sleeping. However, it is only suitable for short-term treatment of insomnia (up to two weeks), as when used for longer periods it has a potential for dependence and addiction.
The medicine should be taken just before going to bed at night, or in bed. It is recommended that this medicine is not taken after a big meal, as this can delay the time it takes for it to get into the blood.
What is it used for?
- Short-term treatment of insomnia.
- This medicine causes drowsiness and impairs concentration and alertness. These effects are made worse by drinking alcohol. If you are affected you should avoid potentially hazardous tasks such as driving or operating machinery. Do not drink alcohol when taking this medicine.
- You should only take this medicine before going to bed at night. If you forget to take it at bedtime dont take it at any other time, or you may end up feeling drowsy, dizzy and confused during the day.
- Only one dose of this medicine can be taken per night, do not take a second dose if you still experience difficulty sleeping after taking the first dose, or if you wake in the night or early in the morning. Consult your doctor if you feel this medicine is not working well enough.
- There have been reports of people doing things while they are asleep after taking this medicine that they do not remember when they wake up. These include sleepwalking, sleep-driving, making phone calls and preparing and eating food. These events may be more likely if you drink alcohol, or take other medicines with sedative effects (see end of factsheet) in combination with this medicine. If you think this could be happening to you, you should let your doctor know.
- This medicine is generally only suitable for short-term use (up to two weeks). If it is used for longer periods or in high doses, dependence upon the medicine may develop and withdrawal symptoms such as headaches, muscle pain, anxiety, tension, restlessness, confusion and irritability and may occur if treatment is stopped suddenly. Your body may also become tolerant to the medicine, with higher doses needed to achieve the same effect. For this reason, you should not exceed the dose of this medicine prescribed by your doctor, or take it for longer than recommended. If you are still having trouble sleeping after this time you should consult your doctor for further advice.
- Depending on how long you have been taking this medicine for, your doctor may suggest that you stop taking it gradually to avoid withdrawal effects or a return in your sleeping problems. Follow the instructions given by your doctor.
Use with caution in
- Elderly people.
- History of alcoholism or drug abuse.
- Decreased kidney function.
- Decreased liver function.
- People with long-term breathing problems.
- History of psychiatric illness.
- People suffering from depression.
Not to be used in
- Children and adolescents under 18 years old.
- Abnormal muscle weakness (myasthenia gravis).
- Severely decreased liver function.
- People with severe breathing problems.
- Syndrome involving short spells when breathing stops during sleep (sleep apnoea syndrome).
- Rare hereditary disorders of galactose intolerance, Lapp lactase deficiency or glucose-galactose malabsorption (Sonata capsules contain lactose).
This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.
If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.
Pregnancy and breastfeeding
Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.
- The safety of this medicine for use during pregnancy has not been established. The manufacturer recommends that it is not used during pregnancy. This is particularly important during the third trimester of pregnancy and prior to or during labour. Regular use of this medicine during the latter stages of pregnancy can cause withdrawal symptoms in the baby. Seek further medical advice from your doctor.
- If you suspect that you could be pregnant, or are planning a pregnancy while taking this medicine you should speak to your doctor about stopping treatment with this medicine.
- Significant amounts of this medicine may pass into breast milk. It should not be used by breastfeeding mothers as it may be harmful to the nursing infant. Seek medical advice from your doctor.
- This medication causes drowsiness. If affected do not drive or operate machinery. Avoid alcoholic drink.
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here does not mean that all people using this medicine will experience that or any side effect.
Common (affect between 1 in 10 and 1 in 100 people)
- Sleepiness (somnolence).
- Pins and needles (paraesthesia).
- Temporary memory loss.
- Painful periods.
Uncommon (affect between 1 in 100 and 1 in 1000 people)
- Loss of appetite.
- Weakness or loss of strength (asthenia).
- A general feeling of being unwell (malaise).
- Numbness in the hands and feet.
- Problems with concentration or memory.
- Depressed mood.
- False perceptions of things that are not really there (hallucinations).
- Problems with coordination, difficulty walking, risk of falling over.
- Changes in vision, such as double vision.
- Speech problems, such as slurred speech.
- Increased sensitivity to noise.
- Abnormal reaction of the skin to light, usually a rash (photosensitivity).
- Allergic reactions, such as narrowing of the airways that causes difficulty breathing (bronchospasm), swelling of the lips, throat and tongue (angioedema) or severe skin reactions.
- Sleeping walking.
- Increase in the levels of certain enzymes in the liver, mainly transaminases.
- Irritability, restlessness or nervousness.
- Aggression or agitation.
The side effects listed above may not include all of the side effects reported by the medicine's manufacturer.
For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.
How can this medicine affect other medicines?
It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you use this medicine. Similarly, check with your doctor or pharmacist before using any new medicines while using this one, to ensure that the combination is safe.
The sedative effect of this medicine will be increased if this medicine is taken with any of the following, which can also cause drowsiness:
- antiepileptics, eg sodium valproate
- antipsychotics, eg chlorpromazine, haloperidol
- barbiturates, eg phenobarbital, amobarbital
- benzodiazepines, eg diazepam, temazepam
- MAOI antidepressants, eg phenelzine
- other sleeping tablets
- sedating antihistamines, eg chlorphenamine, hydroxyzine, promethazine
- strong opioid painkillers, eg morphine, codeine
- tricyclic and related antidepressants eg amitriptyline, maprotiline.
If zaleplon is used with strong opioid painkillers, such as morphine, this can result in an increase in the euphoric effect that these painkillers can have. This could lead to an increased risk of psychological dependence on the painkiller.
The amount of zaleplon in the blood may be increased by the antibiotic erythromycin and by the H2 antagonist cimetidine. These medicines could therefore enhance the sedative effect of zaleplon and increase the risk of its side effects.
The antibiotic rifampicin may decrease the amount of zaleplon in your blood and so could make it less effective.
Other medicines containing the same active ingredient
There are currently no other medicines available in the UK that contain zaleplon as the active ingredient.