How does it work?

Promethazine is derived from a group of medicines called phenothiazines, however, it is also part of the family of sedating antihistamines. Histamine is a chemical in the body that causes the symptoms of an allergic reaction. These can include inflammation of the skin, airways or tissues, rashes, itching of the skin, eyes or nose, nasal congestion and narrowing of the airways. Promethazine blocks the binding of histamine to receptors in many areas of the body and thereby prevents the actions of histamine. This helps prevent and relieve the typical symptoms of an allergic reaction. Histamine may be released from and act in a small (localised) area of the body e.g the nose. Alternatively, histamine can result in a serious or complete body reaction e.g. anaphylactic reaction. Promethazine is useful for the prevention or relief of localised or less serious allergies such as hay fever or itchy rash in addition to serious allergic reactions such as anaphylaxis. Promethazine blocks histamine receptors in an area of the brain called the vomiting centre. It also acts to block other receptors in the vomiting centre (serotonin receptors). Therefore promethazine prevents the vomiting centre from sending the nerve messages to the stomach that would normally result in vomiting. Promethazine also acts on receptors in the gut (muscarinic receptors) to decrease the amount of fluid secreted from the lining of the gut and decrease the actions of the gut muscles. This further aids the treatment or prevention of nausea and vomiting. Promethazine is known as a sedating antihistamine as it enters the brain in significant quantities and causes drowsiness. As a result it is commonly used for the short-term treatment of sleep disturbances and to provide sedation prior to minor procedures or surgery.

What is it used for?

Allergic conditions such as hay fever and itchy rash

Difficulty in sleeping

Life threatening allergic reaction (anaphylactic reaction)

Nausea and vomiting

Sedation prior to surgery (preoperative sedation)

Warning!

This medicine may cause drowsiness. If affected do not drive or operate machinery. Alcohol should be avoided.

This medicine may interfere with some pregnancy tests, causing false negative or false positive results.

This medicine should be discontinued at least 72 hours before allergy skin tests, as it may cause false negative results.

The elixir is unsuitable for diabetics as it contains glucose syrup.

The elixir should not be used for longer than 7 days without seeking medical advice.

Avoid exposure to strong sunlight while taking this medicine.

This medicine is only intended for the short term treatment of insomnia.

Use with caution in

Asthma

Blockage of the area where the stomach joins the intestines (pyloro-duodenal obstruction)

Blockage of the drainage passage of the bladder (bladder neck obstruction)

Bronchitis

Closed angle glaucoma

Decreased kidney function

Decreased liver function

Epilepsy

Severe coronary artery disease

Widening of the airways which may be hereditary or due to infection (bronchiectasis)

Not to be used in

Allergy to phenothiazines such as chlorpromazine and prochlorperazine

Children less than 2 years of age particularly premature or newborn babies

Diabetes mellitus (note: this only applies to the use of the syrup / elixir form of this medicine)

Reduced awareness, slow reactions or drowsiness due to medicines or illness that reduce activity in the central nervous system

Unresponsive unconscious states (comatose states)

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.

This medicine can be used with caution during pregnancy. However, it should not be used in the last two weeks of pregnancy due to the risk of adverse effects the baby may experience. Seek medical advice from your doctor.

Small amounts of this medicine may pass into breast milk. There are risks of harmful effects to the nursing infant. Seek medical advice from your doctor.

Label warnings

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

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