Cyclizine

Cyclizine is an antihistamine medication. It’s used to help stop you feeling sick (nausea) or being sick (vomiting or emesis).

You can take cyclizine to treat symptoms of nausea or vomiting caused by morning sickness, vertigo, inner ear problems such as motion sickness or Ménière’s disease. It’s also helpful at treating nausea caused by general anaesthetics after surgery, cancer treatment or other medicines.^[1]

Cyclizine is an antihistamine, meaning it works by blocking a chemical called histamine in your brain that can make you feel sick. It belongs to a class of medicines called histamine H1 receptor antagonists. Its exact mechanism of action against nausea or how it stops you from vomiting, however, is not yet fully known.

We do know, however, that it strengthens the lower oesophageal sphincter (a muscle at the bottom of your food pipe, just above the stomach), which helps prevent vomiting. This is because vomiting can occur when the lower oesophageal sphincter is relaxed. It’s also thought to inhibit a part of your brain known as the emetic centre (more commonly known as the vomiting centre) which, when stimulated, can make you vomit.

Cyclizine also reduces the sensitivity of your inner ear, which is helpful if nausea and vomiting are symptoms of an inner ear problem like motion sickness.^[2]

Cyclizine comes as Cyclizine 50mg tablets and is also available as a Cyclizine Lactate 50mg/ml injection.

When used to treat nausea, the recommended dose for Cyclizine tablets for adults is one to three tablets a day when needed (with at least 8 hours between doses).

If you suffer from motion sickness, take your tablets 1-2 hours before you’re due to travel.

Remember to always take Cyclizine tablets exactly as your clinician has prescribed them. Take them whole with water, with or without food.

Taking more than the recommended amount of Cyclizine can cause symptoms of overdose, which can include dry mouth, blurred vision, fast heartbeat, drowsiness, dizziness, loss of balance and coordination, disorientation, impaired judgement, hallucinations, involuntary movements of your lips, tongue or face, convulsions, fever or difficulty breathing.

If you think you’ve overdosed on Cyclizine, go to the nearest hospital immediately or contact your clinician. Take the package or any remaining tablets with you to show the doctor what you’ve taken, if you can.

If you forget to take a dose, just take the next one as scheduled. Don’t double your dose to make up for the missed one.

Cyclizine takes about 30 minutes to start working, but it reaches peak plasma concentrations (maximal effect) after about two hours.^[1] This is why it’s recommended that you take it 1-2 hours before departure when you have motion or travel sickness.

When you take Cyclizine orally, the effects of it usually last for about 4-6 hours.^[1] But this varies from person to person, so your response to the medication may be slightly different.