Cyclizine (Valoid injection)

How does it work?

Valoid injection contains the active ingredient cyclizine, which is a type of medicine called an antihistamine. It is mainly used to prevent and treat nausea and vomiting following surgery or radiotherapy, or associated with middle ear disorders. (NB Cyclizine injection is also available without a brand name, ie as the generic medicine.)

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 the vestibular apparatus in the middle ear.

The vestibular apparatus provides continual feedback to the brain about our body position. When something disturbs the vestibular apparatus, such as head movement following surgery or motion when travelling by boat or car, nerve signals are sent from the vestibular apparatus to the vomiting centre. This can cause sensations such as nausea, dizziness or spinning sensations (vertigo) and the reflex of vomiting.

Cyclizine works by blocking histamine and muscarinic receptors in the vomiting centre, which prevents the vomiting centre from receiving nerve messages from the vestibular apparatus. This prevents disturbances in the middle ear from activating the vomiting centre and causing nausea, vertigo and vomiting.

Cyclizine may also prevent the vomiting centre from receiving messages from an area of the brain called the chemoreceptor trigger zone (CTZ). The CTZ is stimulated by agents circulating in the blood, for example anaesthetics and opioid painkillers such as morphine. Cyclizine helps prevent these agents from activating the vomiting centre and causing sickness.

Cyclizine also tightens the muscles at the entrance to the stomach which can physically help to prevent the stomach contents from flowing back out of the stomach. Cyclizine injection can be given to people having emergency surgery in order to reduce the risk of regurgitating and inhaling the stomach contents while under general anaesthetic.

Cyclizine is given by injection when taking tablets is not possible.

What is it used for?

  • Preventing and treating nausea and vomiting following surgery or radiotherapy
  • Relieving nausea, vomiting and attacks of vertigo associated with Meniere's disease and other middle ear disorders
  • Preventing and treating travel sickness
  • Preventing regurgitation and inhalation of the stomach contents in emergency surgery

Use with caution in

  • Decresed kidney function
  • Liver disease
  • Enlarged prostate gland (prostatic hypertrophy)
  • Glaucoma
  • Obstruction of the stomach or intestines
  • Severe heart failure
  • Epilepsy.

Not to be used in

  • Allergy to any ingredient
  • Hereditary blood disorders called porphyrias.

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 fully established. As with all medicines, it should only be used during pregnancy if the potential benefits outweigh any potential risks to the foetus. Seek medical advice from your doctor.
  • It is not known if this medicine passes into breast milk. Seek medical advice from your doctor.

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. Because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.

  • Reactions such as redness and pain at the injection site
  • Rash
  • Drowsiness
  • Headache
  • Dry mouth, nose or throat
  • Blurred vision
  • Faster than normal heart beat (tachycardia)
  • Difficulty in passing urine (urinary retention)
  • Constipation
  • Restlessness
  • Difficulty sleeping (insomnia)
  • Nervousness
  • False perceptions of things that are not really there (hallucinations)
  • Abnormal movements of the hands, legs, face, neck and tongue, eg tremor, twitching, rigidity
  • Dizziness
  • Convulsions
  • Pins and needles sensations
  • Increased blood pressure
  • Jaundice

The side effects listed above may not include all of the side effects reported by the drug'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 start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while having treatment with this one, to ensure that the combination is safe.

There may be an increased risk of drowsiness if this medicine is used with any of the following (which can also cause drowsiness):

  • alcohol
  • antidepressants, eg amitriptyline
  • antipsychotics
  • opioids, eg morphine, codeine
  • benzodiazepines, eg diazepam
  • sedating antihistamines, eg chlorphenamine, promethazine
  • sleeping tablets.

If this medicine is used with other medicines that have antimuscarinic effects there may be an increased risk of side effects such as blurred vision, dry mouth and constipation. Other medicines with antimuscarinic effects include the following:

  • antihistamines, eg promethazine, chlorpheniramine
  • antispasmodics, eg atropine, propantheline, oxybutynin
  • antimuscarinic medicines for Parkinson's symptoms, eg procyclidine
  • antipsychotics, eg chlorpromazine, clozapine, thioridazine
  • antiarrhythmics, eg disopyramide, propafenone
  • certain antidepressants, eg amitriptyline, maprotiline
  • muscle relaxants, eg baclofen
  • certain other antisickness medicines, eg promethazine, meclozine.

Other medicines containing the same active ingredient

Valoid tablets

Cyclizine injection is also available without a brand name, ie as the generic medicine.