Used to treat the nausea and vomiting caused by radiation therapy, cancer chemotherapy, surgery, and other conditions. It also is used to treat psychotic symptoms such as hallucinations and hostility.

How does it work?
Stemetil tablets, syrup, injection and suppositories all contain the active ingredient prochlorperazine, which is a type of medicine called a phenothiazine. (NB. prochlorperazine is also available without a brand name, ie as the generic medicine.) Prochlorperazine has two quite different uses. In higher doses it is used in the treatment of psychiatric illnesses. In lower doses it is used in the management of nausea and vomiting.
When used in psychiatric illness, prochlorperazine is sometimes described as a neuroleptic or a `major tranquilliser`. However this last term is fairly misleading, as this type of medicine is not just a tranquilliser, and any tranquillising effect is not as important as its main mechanism of action in psychiatric illness.
Prochlorperazine works by blocking dopamine receptors in the brain. Dopamine is a natural compound called a neurotransmitter, and is involved in transmitting messages between brain cells. Dopamine is a neurotransmitter known to be involved in regulating mood and behaviour, amongst other things.
Psychotic illness, and particularly schizophrenia, is thought to be caused by overactivity of dopamine in the brain. Prochlorperazine blocks the receptors that dopamine acts on, and this prevents the overactivity of dopamine in the brain. This helps to control psychotic illness.
Prochlorperazine is used in the long-term management of psychotic conditions such as schizophrenia. It is also used in the short-term to manage severe anxiety or acute mania.
Prochlorperazine also affects dopamine receptors in an area of the brain that controls nausea and vomiting. Vomiting is controlled by an area of the brain called the vomiting centre. The vomiting centre is responsible for causing feelings of sickness (nausea) and for the vomiting reflex. It is activated when it receives nerve messages from another area of the brain called the chemoreceptor trigger zone (CTZ) and when it receives nerve messages from the gut.
Prochlorperazine controls nausea and vomiting by blocking dopamine receptors found in the CTZ. This stops the CTZ from sending the messages to the vomiting centre that would otherwise cause nausea and vomiting.

What is it used for?
In adults, Stemetil is used for the conditions below.
- Psychotic illness such as schizophrenia.
- Acute mania.
- Short-term treatment of severe anxiety.
- Treatment and prevention of nausea and vomiting.
- Relieving nausea, vomiting and attacks of dizziness or spinning sensations (vertigo) associated with Meniere`s disease and other inner ear disorders.

In children aged over one year and weighing more than 10kg, Stemetil tablets or syrup may be used for:
- Treatment and prevention of nausea and vomiting.

Use with caution in
- Elderly people.
- Decreased kidney function.
- Decreased liver function.
- Heart disease.
- Slow heart rate (bradycardia).
- People with a personal or family history of an abnormal heart rhythm seen on a heart monitoring trace (ECG) as a `prolonged QT interval`.
- People with low levels of potassium, calcium or magnesium in the blood (hypokalaemia, hypocalcaemia or hypomagnesaemia).
- Malnutrition.
- Dehydration.
- Alcohol abuse.
- Elderly people with dementia (antipsychotic medicines have been shown to increase the risk of stroke in this group of patients).
- People with risk factors for having a stroke, for example a history of stroke or mini-stroke (TIA), smoking, diabetes, high blood pressure, or a type of irregular heartbeat called atrial fibrillation.
- Underactive thyroid gland (hypothyroidism).
- Tumour of the adrenal gland (phaeochromocytoma).
- Enlarged prostate gland (prostatic hypertrophy).
- Parkinson`s disease.
- Abnormal muscle weakness (myasthenia gravis).
- History of seizures (fits) eg epilepsy.
- People with conditions that increase the risk of epilepsy or convulsions, eg brain damage or withdrawal from alcohol.
- History of closed angle glaucoma.
- History of a drop in the normal number of white blood cells in the blood.
- Allergy to other phenothiazine medicines, eg chlorpromazine, trifluoperazine.

Not to be used in
- Children (except for the management of nausea and vomiting - see above).
- Breastfeeding.

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 during pregnancy has not been established. It should not be used in pregnancy unless considered essential by your doctor. Seek medical advice from your doctor.
- This medicine may pass into breast milk. As it could cause drowsiness and potentially other side effects in a nursing infant, it is recommended that women who need treatment with this medicine should not breastfeed. Seek further medical advice from your doctor.

Label warnings
- This medication may cause drowsiness. If affected do not drive or operate machinery. Avoid alcoholic drink.

Side effects

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.
- Abnormal movements of the hands, legs, face, neck and tongue, eg shakiness, twitching, rigidity.
- Anxiety, restlessness and agitation (akathisia).
- Rhythmical involuntary movements of the tongue, face, mouth and jaw, which may sometimes be accompanied by involuntary movements of the arms and legs (tardive dyskinesia - see warning section above).
- A drop in blood pressure that occurs when moving from a lying down or sitting position to sitting or standing, which results in dizziness and lightheadedness (postural hypotension).
- Drowsiness.
- Dry mouth.
- Difficulty sleeping (insomnia).
- Skin rashes.
- Stuffy nose.
- Increased sensitivity of the skin to UV light (photosensitivity - see warning section above).
- Interference with the body`s temperature regulation (this is more common in elderly people and can cause heat stroke in very hot weather or hypothermia in very cold weather).
- Decrease in the numbers of a type of white blood cell (neutrophil) in the blood (neutropenia).
- Sudden severe deficiency in the number of white blood cells in the blood (agranulocytosis).
- Abnormal heart beats (arrhythmias).
- Yellowing of the skin and eyes (jaundice).
- High blood prolactin (milk producing hormone) level (hyperprolactinaemia). Rarely this may lead to symptoms such as breast enlargement or production of milk.
- Impotence.
- Changes in menstrual periods.
- High temperature combined with falling levels of consciousness, paleness, sweating and a fast heart beat (neuroleptic malignant syndrome). Requires stopping the medicine and immediate medical treatment - see warning section above.

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.