Procyclidine

How it works

What does procyclidine do?

There is a naturally-occurring chemical messenger ('neurotransmitter') in the brain called acetylcholine. Acetylcholine is involved in thinking, emotions, behaviour and perception. It is also linked with movement and muscle activity.

In the brain, acetylcholine sits in balance with dopamine, another neurotransmitter. Picture the two neurotransmitters sitting in balance either side of a see-saw.

When you take antipsychotic medication, it reduces the activity of dopamine. This upsets the balance between acetylcholine and dopamine, which leads to movement problems.

If we think about the see-saw, the dopamine has now become light and the acetylcholine has become heavy.

Procyclidine helps re-balance the see-saw. It does this by reducing the activity of acetylcholine.

Procyclidine reduces acetylcholine activity by blocking acetylcholine target sites (receptors). Drugs that block target acetylcholine receptors are called anticholinergics or anti-muscarinics.

How long does procyclidine take to start working?

You should see positive results right from the first week.

However, getting the right dose may take a little longer. The aim is to get the movement symptoms under control without giving you extra side effects from the procyclidine.

You should stay in touch with your doctor to see how it goes over the first few weeks. They may do some tests to check your symptoms.

How long will I need to take procyclidine for?

You and your doctor should talk about how long you will need to take procyclidine.

It is likely that your doctor will tell you to continue taking procyclidine alongside your current antipsychotic for as long as it is helpful.

If you change the antipsychotic that you take, your procyclidine should be reviewed as well.

Your doctor needs to know if...

You should tell your doctor or pharmacist before you start taking procyclidine if you have, or have a history of these conditions:

• Parkinson's
• prostate problems
• paralytic ileus (a blocked intestine)
• epilepsy or seizures (fits)
• narrow-angle glaucoma (increased pressure in the eye)
• respiratory (lung) disease

Taking procyclidine

How can procyclidine be taken?

Procyclidine can be taken as tablets, an oral solution or given by injection in an emergency.

The tablets contain lactose, so they may not be suitable for you if you have problems eating some sugars or dairy (milk-based) foods.

The oral solution has a type of sugar called maltitol in it. Please let your doctor or pharmacist know if you have trouble digesting some sugars like fructose. This should not affect your blood sugars if you are diabetic.

The injection is for emergency use and would be given to you by a doctor or nurse if you develop a sudden movement problem where your muscles lock or freeze.

You should only take procyclidine as agreed with your doctor

You will get the best effect from procyclidine if you take it as advised by your doctor.

Make sure that you know your dose. If it is not written on the label, check with your pharmacist or doctor.

Your dose will be adjusted to give you the best control of movement difficulties with as few side effects as possible.

You may need to take your procyclidine more than once a day.

It is usually recommended that you avoid taking it before bedtime, as it may keep you awake.

However, it is important to choose a time of day that you can remember easily to take it, which could be a mealtime, or when you brush your teeth.

It is best if you take it after food.

If you take the tablets, swallow them whole with a drink of water - if you chew them, they taste bitter.

The injection is for emergency use and would be given to you by a doctor or nurse if you develop a sudden movement problem where your muscles lock or freeze.

What if I miss a dose?

If you remember during the day, take it as soon as possible.

If you forget to take it by bedtime, just start again the next day.

If it is less than eight hours before your next dose of procyclidine, then do not take the missed dose as taking the doses too close together could cause more side effects.

What will happen if I forget to take my procyclidine?

If you forget to take your tablets for a while, your movement-related side effects may come back. You should talk to your doctor if this happens.

Do not take a double dose.

Stopping the use of procyclidine

When you stop taking procyclidine, the balance of chemicals in the brain changes.

Stopping this medication suddenly, or reducing the dose too much at once, may cause the acetylcholine receptors to go into overdrive. This may cause withdrawal effects, such as:

• nausea and vomiting
• diarrhoea
• muscle cramps
• excess saliva and tears

If you want to stop taking procyclidine, it is better to do so under a doctor's supervision. They will help you reduce your dose gradually over a few weeks. You will probably go for checks with your doctor after you stop procyclidine to check that you still feel better.

The information on this page was reviewed by the College of Mental Health Pharmacy in March 2020.

Safety headlines

If you have taken more procyclidine than the dosage recommended by the doctor who prescribed it to you, you must get medical help immediately – even if you do not feel any different.

Taking too much procyclidine can cause serious side effects, including:

• flushing
• dilation (widening) of the pupils
• blurred vision
• dry mouth and tongue
• hot, dry skin
• fever
• constipation (difficulty pooing)
• difficulty peeing
• changes to your heart rate (speeding up or slowing down)
• raised blood pressure
• raised breathing rate

You should go to hospital immediately, and tell the doctor you're taking procyclidine, if you develop a combination of fever, faster breathing, sweating, muscle problems, or a big change in your heart rate.

You might notice that your thinking is a little slower in the first few days after taking procyclidine. Do not drive a car, ride a bike, or operate machinery until you see how this affects you.

Stopping procyclidine suddenly can cause withdrawal effects. Stopping it while you're still taking your antipsychotic medication may cause your movement-related side effects to return. If you want to stop taking procyclidine, it is better to do so with the help of your doctor.

If you are pregnant, or thinking of trying to become pregnant, please read the 'Pregnancy' section (under the 'Side effects: sex, drink and life' tab) as procyclidine may affect the developing baby.

When to go to the hospital

If you have taken more procyclidine than the dosage recommended by the doctor who prescribed it to you, you must get medical help immediately – even if you do not feel any different. Go to A&E. Take your medicine with you to show to the doctors. Tell them how much you have taken. Get a friend or family member to go with you if you can, in case you feel ill on the way.

You may get any of the following signs:

• very slow heart rate followed by rapid beating of the heart
• agitation/aggressiveness
• speech problems
• difficulty peeing
• blurred vision and dilated (wide) pupils
• reduced level of consciousness or coma
• confusion
• seizures (fits)
• a combination of fever, faster breathing, sweating, muscle stiffness and drowsiness or sleepiness, slower breathing, aspiration (breathing in vomit, mucus or blood), high blood pressure and unusual heart rhythms

Go to hospital or see a doctor straight away if you get any of the following symptoms:

• allergic reaction (difficulty breathing, swelling of your face or throat, itching skin lumps)
• glaucoma (increased pressure inside the eyes - symptoms of which include: eye pain, red eyes, headache, tenderness around the eyes, blurred vision and seeing rings around lights)
• any combination of fever, faster breathing, sweating, muscle stiffness and drowsiness or sleepiness

Another possible - but rare - side effect of antipsychotic medications is repeating movements of the tongue, mouth and face. This is called tardive dyskinesia and is more common with older antipsychotic medications.

The first sign might be experiencing movements of your tongue that you cannot control, which may be quite regular and rhythmic.

The problem with tardive dyskinesia is that it might not stop, even if you stop taking your medicine. It is not helped by procyclidine - in fact, procyclidine may make it worse.

If you notice tardive dyskinesia early and take action with your doctor, the problem should not get worse, so go and see your doctor straight away if you get the above symptoms.

Side effects

Like all medications, procyclidine may cause some side effects, and in some cases they can be serious.

However, most side effects are mild and should get better within a few days. If they do not, you should go back to your doctor.

Common side effects (affecting up to one in ten people) include:

• constipation
• dry mouth
• blurred vision
• difficulty peeing

Please do not be worried by the side effects listed on this page. Some people take procyclidine without any side effects or only a few mild side effects. Some side effects wear off after a few days or weeks.

If you think you might be getting a side effect from procyclidine, then you should discuss this with your doctor, nurse, or pharmacist.

Body

Procyclidine itself is unlikely to affect your weight, but it is often taken with antipsychotic medications which may cause weight gain.

Talk to your doctor about this if it worries you.

You should have your weight checked, and have some blood tests, when you start taking your antipsychotic. You should then have your weight, blood sugar, blood fats, blood pressure and pulse measured regularly during the early stages of your treatment and then at least every six months after that, depending on your age.

The doctor may also check your heart with an ECG (electrocardiogram).

They may also check your height and development, and, if you have periods, whether your periods are regular.

It is very important to go for these checks when you are asked to do so.

Sex and fertility

Sex

Procyclidine is often taken to treat the side effects of an antipsychotic medication. If you are taking it for this reason, you should check whether the antipsychotic medication you take causes side effects that may affect your sex life. See our Medications page for more information.

Fertility

Procyclidine is unlikely to affect fertility, but you should talk to your doctor if you are planning to get pregnant.

Procyclidine is often taken to treat the side effects of an antipsychotic medication. If you are taking it for this reason, you should check whether the antipsychotic medication you take affects your fertility. See our Medications page for more information.

Pregnancy and breastfeeding

Pregnancy

As procyclidine is usually taken to help with side effects caused by other drugs (usually antipsychotics), studies do not look at the effects on developing babies of procyclidine on its own.

It is a good idea to look at the information available for the antipsychotic medication you are taking. This should be available on our Medications page.

Breastfeeding

We do not know how much procyclidine is transferred through breast milk, so most information sites will say not to breastfeed your child if you are on this medication. However, it is your choice.

If your baby is healthy and full-term, and you do decide to breastfeed, keep an eye out for side effects in your baby like constipation, difficulty peeing, and a fast pulse.

If your baby was premature or has health problems, then you will need to be extra careful about taking medicines while breastfeeding.

If your baby becomes restless, very sleepy, or develops feeding problems, then stop breastfeeding and seek medical advice immediately.

Talk to your doctor or midwife about feeding options.

Driving and transport

Taking procyclidine may make you feel tired or dizzy when you start taking it. It will also slow down your reaction time. This could affect you if you drive a car, ride a bike, or do anything that needs a lot of focus. It might be best to stop doing these things for the first few days, until you know how it affects you.

Don't worry - most people drive as normal while taking procyclidine.

School and exams

Procyclidine can make you feel tired or dizzy, and it may affect your memory.

You should talk to your doctor about any future exams before you start taking procyclidine. You might decide together to delay starting it until you have done them. You might find that it is better, however, to start procyclidine to improve your overall wellbeing and your ability to study for your exams.

Don't worry - most people take exams as normal while taking procyclidine.

Friends and family

You may want to let your family and friends know you are taking procyclidine 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.

Sport

Procyclidine is not a banned substance in sport.

However, it can make you feel tired or dizzy, which may affect your performance in sports that require a lot of focus.  You may want to stop these sports for a few days when you first start taking procyclidine until you see how it affects you.

Don't worry - most people play sports as normal while on procyclidine.

Alcohol, street drugs and smoking

Alcohol

You can drink alcohol while taking procyclidine, but it may make you sleepy and make you fall over. If you drink a lot alcohol, these effects will be more serious.

Drinking a lot of alcohol can also make the symptoms of your condition worse.

It might be best to stop drinking alcohol for a few days when you start taking procyclidine until you know how the medicine affects you.

If you want to drink alcohol while on procyclidine, remember that it may make you sleepy, so make sure you can get home safely.

Street drugs

Procyclidine does not mix well with street drugs.

Cannabis and procyclidine taken together increases your heart rate and may also make any drowsiness worse.

Amfetamine and procyclidine taken together increases your heart rate.

Methadone can make the more common side effects of procyclidine (such as dry mouth, blurred vision and constipation) worse.

If you are taking procyclidine to help treat the side effects of an antipsychotic medication, it is important to look up how your antipsychotic medication interacts with other drugs. For more information, look at our Medications page.

Procyclidine on its own can, in large doses, cause a high and make psychosis symptoms worse. Do not share your procyclidine with anyone else.

Smoking

Cigarette smoke does not affect the amount of procyclidine in your body, so you shouldn't have to change your dose of procyclidine if you start or stop smoking while on it.

Prescription medicines

Procyclidine does not mix well with some other medicines and drugs, so you should always tell your doctor if you are taking other medication before you start taking procyclidine.

You should also tell your pharmacist you are taking procyclidine if you buy medicines for common illnesses, including things you put on your skin.