Your guide to medication Chlorpromazine

It can take a few days for chlorpromazine to take effect. It’s difficult to determine how long you can expect to wait, as the medication affects each person differently.

If you have had no change after three to four days of taking chlorpromazine, talk to your doctor. Don’t increase your dose yourself if you think the medication isn’t working.

Your weight could be affected by taking chlorpromazine. It’s very difficult to know how much weight (if any) you might gain, as each person is affected differently.

Your doctor should weigh you before you start taking chlorpromazine and every week for the first three months. They should then check your weight and waist measurement at least every six months. You can also do this yourself at home and keep a chart to show your doctor.

Young people naturally gain a little weight each year as they grow, but anything more than this should be monitored.

If you put on a large amount of weight while taking this medication, there are lots of other antipsychotic medications you can try. You can also take steps to lose any excess weight through healthy eating and exercise.

Talk to your doctor if weight gain while taking this medication worries you.

People taking chlorpromazine can also get some growth of the breasts and some milk flow when taking this medication, regardless of gender.

Your skin colour can be affected by chlorpromazine if you take it for a long time, taking on a blue-grey tint. This is because it increases the amount of melanin in your skin (the pigment that makes your skin go darker when you have a tan).

Melanin can also build up in your eyes although this should not affect your eyesight.

Your skin may also burn more easily in the sun while taking this medication and you could get rashes or other skin reactions from too much UV light. For this reason, you should not use a tanning bed while taking chlorpromazine. Spray-tanning is fine and a much safer option in general.

If you are exposed to the sun, use plenty of high-factor sunscreen and cover up whenever possible.

You may want to let your family and friends know you are taking chlorpromazine so they can support you and help you look out for side effects.

For guidance on this, check out our page on getting support with your medication.

Chlorpromazine can affect your sleep in a few different ways – you may feel more tired and sleep more than normal, you may find it difficult to get to sleep, or you may experience nightmares.  

Things should settle after the first few days. If not, you should go back to your doctor and talk through your options.

Alcohol

When you first start to take this medication, combining alcohol with chlorpromazine will make you feel very sleepy, so you should avoid it altogether.

Once your body has got more used to the chlorpromazine, this effect should be reduced. It’s best to stick to drinking only small amounts of alcohol and to have a plan for getting home safely.

Street drugs

Be careful if you are also using street drugs, as antipsychotics like chlorpromazine block the effect of dopamine, meaning that the ‘high’ you are used to may not be as potent as before. This could lead you to increase the dose of the street drug to make up for it, which could be very dangerous.

Smoking

Cigarette smoke affects the amount of chlorpromazine in your body. So, if you start or stop smoking while you are taking chlorpromazine, you may have to change your dose.

If you already smoke when you begin taking this medication, you will probably need a higher dose than somebody who does not smoke. You should tell your doctor if you smoke and how much, so that he or she can prescribe the correct dose for you.

It is the smoke, rather than nicotine, that has this effect so it should not be a problem if you only vape.

Chlorpromazine does not mix well with some other medications.

Tell your doctor or pharmacist if you are taking any other kind of medication as they may need to change your dose of chlorpromazine or prescribe you a different medication.

Other medications include tablets or liquids that you buy over the counter to treat common illnesses such as colds and flu, or topical medications that are applied to the skin.

Chlorpromazine may cause problems for people with certain allergies or intolerances:

• Chlorpromazine tablets contain lactose and may not be suitable for people who have problems eating some sugars or dairy (milk-based) products.
• Chlorpromazine oral syrup contains sorbitol and sugars; methyl, ethyl and propyl parahydroxybenzoates (additives that can cause allergies in some people); and a small amount of alcohol (though not enough to cause a change in your blood levels).
• Chlorpromazine sugar-free oral solution contains: sorbitol and sugars; aspartame (not suitable for people with a condition called phenylketonuria); sunset yellow E110 (an additive causing allergies in some people); and a small amount of alcohol (though not enough to cause a change in your blood levels).
• Chlorpromazine injections contain sulphites that can cause allergies in some people.

There are many manufacturers of liquid chlorpromazine products so talk to your pharmacist if you are concerned about any of chlorpromazine’s ingredients and their potential effects.

Chlorpromazine may make you feel very tired and woozy when you start taking it, and it may affect your eyesight, so you should not ride a bike or drive a car until you become used to this medication. Arrange alternative methods of transport for a few days or weeks until you know how you will be affected.

You should also be very careful when doing anything else that requires concentration, such as operating machinery or exercising.

Don’t worry – most people are able to drive or ride a bike as normal once they are settled on chlorpromazine. 

Pregnancy

Chlorpromazine has been used in humans during pregnancy for a long time with no signs of increased risk to you or your unborn baby.

Babies do better when their mums are mentally well, so if chlorpromazine has beneficial effects on your mental health, it may be best to continue taking it throughout pregnancy. Your doctor can help you weigh up the pros and cons.

Pregnant woman are advised to take folic acid – this is safe to do while also taking chlorpromazine.

You may also be checked for increased risk of blood clots during pregnancy and may be prescribed a course of blood-thinning injections. This is standard practice and nothing to worry about.

Women taking more than 500mg a day of chlorpromazine may have a longer labour than might normally be expected. 

Post-natal

You should talk to your doctor or midwife to discuss plans for after the birth.

Chlorpromazine can cause side effects in newborn babies including withdrawal symptoms.  This could mean that your baby is either very sleepy or very excited, could shake and/or have weak or stiff muscles. Your baby may also have difficulty sleeping and breathing.

Breastfeeding

Chlorpromazine is passed to the baby in breast milk, but only in small amounts.

Talk to your midwife or doctor to discuss feeding options before your baby is born, so that you can be prepared.

Breastfeeding might be beneficial in offsetting some of the withdrawal effects in your baby.

Sex

Chlorpromazine can have side effects that might affect your sex life. These include:

• an erection that is painful and lasts for a long time (priapism) can occur when taking chlorpromazine. If this happens, you should see your doctor straight away
• difficulty having an orgasm (coming/climaxing), or having an orgasm without ejaculating (no sperm comes out)
• lighter periods, or no periods at all. If you normally have periods, your doctor should monitor this while you are taking chlorpromazine

If you experience any of these symptoms, talk to your doctor.

After you have taken chlorpromazine for a few weeks, you should begin to feel the benefits of the medication which may include improvements in your relationships and, consequently, your sex life.

Fertility

You should tell your doctor if you are pregnant or trying for a baby before taking chlorpromazine.

Chlorpromazine can affect your fertility. This is because it increases the amount of the hormone prolactin in the body. Prolactin is the hormone released by breastfeeding, which may have some contraceptive effect (may make it harder to get pregnant).

Make sure you use a reliable method of contraception while you are taking chlorpromazine if you do not wish to become pregnant. If you’re not sure what method to use, visit your doctor or make an appointment at a sexual health clinic to discuss your options.

If you become pregnant while taking chlorpromazine, you should let your doctor know immediately.

Chlorpromazine is not a banned substance in sport.

It may make you feel tired and woozy, and affect your eyesight when you first start taking it, so you may wish to stop playing sports for the first few days, until you know more about how it affects you.

Don’t worry, most people can play the sports they normally enjoy while taking this medication.

Talk to your doctor before starting to take chlorpromazine if you are about to sit any exams or tests, as the medication can initially make you feel very tired and woozy, and it may affect your eyesight. You might decide together to delay starting it until you have done them, or your doctor might suggest some alternative medications.

If your exams are more than a week away, however, you may decide with your doctor that it’s better to start taking chlorpromazine to improve your motivation to study.

Try not to worry – most people take exams and tests as normal while on chlorpromazine.