Cyclizine

What is Cyclizine?

Cyclizine belongs to the group of medicines called antihistamines and is also an antiemetic drug (a drug that prevents nausea and vomiting). It’s licensed to treat nausea, but is an off-label treatment for morning sickness (nausea during early pregnancy).

Morning sickness is common in the early stages of pregnancy. It’s thought that around 70-80% or pregnant women will get nausea or vomiting.^[1]
It can be caused by many things, including hormonal changes, like increased levels of hCG (pregnancy hormone), which can make you feel sick. Although morning sickness is normal, severe nausea and vomiting can be harmful to yourself and your baby.^[2]

Taking Cyclizine blocks the signals sent to the vomiting centre, relieves feelings of nausea, and lowers the risk of vomiting.

How does Cyclizine work?

Cyclizine is an antiemetic drug used to relieve symptoms of nausea and vomiting. It has antihistamine properties, which make you stop feeling nauseous. Histamine is a chemical that’s known to cause allergic reactions and hives. However, it’s also one of the main chemicals that controls your brain’s nausea centre.^[3]

When an excess of histamine binds to its H1 receptors, it can trigger feelings of nausea. Cyclizine works by binding to these receptors and blocking histamine signals. This helps alleviate nausea, making you feel less sick.^[4]

Furthermore, your inner ear is responsible for maintaining balance and movement. It also contains H1 receptors. So, when excess histamine binds to these receptors, it can alter your balance, potentially leaving you feeling dizzy and sick.^[5]
This can further contribute to feelings of nausea.

Nausea and vomiting are complex processes, so Cyclizine will only be effective for you if high histamine levels are the primary issue causing sickness.

How to take Cyclizine

Always follow your prescriber’s instructions when taking Cyclizine.

• Cyclizine is available in a single dose of 50mg.
• The usual dose is one to three tablets a day.
• If you’re taking three tablets daily, make sure there is a minimum of 8 hours in between each dose.
• Your clinician will decide what your dosage is and for how long you will take it for.
• It can be taken with or without food but should be swallowed with water.

If you’re not sure about anything to do with this medicine, ask your clinician for advice.

How long does it take for Cyclizine to work?

Within 2 hours of taking Cyclizine, you should start to feel less nauseous. This effect will last approximately 4 hours.

After the effects wear out, don’t take another tablet straight away. There should be a minimum of eight hours between each dose.

What should I do if I make a mistake when taking Cyclizine?

Taking more than the recommended amount can cause symptoms such as dry mouth, blurred vision, irregular heartbeat and more. If you accidentally take more, contact your doctor immediately.

If you forget to take a dose, take it when you remember. However, if it’s close to your next dose, skip the one you missed, and never take a double dose.