Clozapine factsheet

Clozapine is available under the brand names Clozaril and Clopine. There are also different ways to take clozapine, tablets, orodispersible ('melt in your mouth') tablets, and liquids.

Knowing these different names is important because prices can vary, some pharmacies might not stock a particular brand, and other brands could have slightly different ingredients or effects. If you notice a change in the brand of clozapine you're taking, be sure to discuss it with your doctor or pharmacist.

Research indicates that approximately one-third of individuals using clozapine begin to experience benefits within the first six weeks. After a year, that number rises to two-thirds. If you're starting clozapine, you may notice some positive changes in the first few weeks, but it may take a bit longer to experience significant improvements.

When you begin treatment, you'll start with a low dose of clozapine, and your doctor will gradually increase (titrate) the dose to find what works best for you. They'll also check your blood levels to ensure you are getting a safe and effective dose of the medication.

Sedation (tiredness)

Clozapine can cause feelings of sleepiness, tiredness, or weakness. Some people describe it as a sensation of heaviness or a feeling of being jet-lagged. Sedation often occurs soon after taking clozapine, so it's important to plan the timing of your doses to fit your daily routine.

For some individuals, this tiredness may improve, while others may continue to experience these effects. Sedation can impact motivation to study, work, or socialise. Consider discussing supportive measures with your workplace or school if this becomes an issue.

Constipation

It is common for those on clozapine to experience constipation. You should inform your doctor if your bowel habits change. If you notice a decrease in the number of bowel movements you usually experience in a week or find it harder to have a bowel movement, contact your doctor immediately.

Saliva changes

Many people may experience increased saliva production, resulting in drooling or dribbling, especially at night. Specific pillows are available to help, as well as medications to reduce this. This side effect usually occurs early in treatment and often improves after the first few months, but it can persist for some.

Feeling dizzy or faint

Some individuals may feel dizzy or faint when changing positions, such as moving from lying down to sitting or from sitting to standing. Counting to five before moving can help your body adjust. Avoid activities such as driving or using stairs if you feel dizzy or lightheaded.

Higher blood sugar

Clozapine can change how your body handles sugar, which might lead to higher blood sugar levels. This can affect your appetite, cause weight gain, and, over time, increase your risk of getting diabetes.

If you already have diabetes, clozapine could make things worse. It's important to keep an eye on your blood sugar using your blood glucose monitor. You should also talk to your doctor about getting a blood test to check your levels. Sticking to a healthy diet, regular exercise, and continuing a healthy lifestyle can help manage these issues.

Weight and appetite changes

Clozapine tends to lead to weight gain more than other antipsychotic medications, usually happening within the first year of treatment. How much weight you gain can differ quite a bit from person to person, making it difficult to predict how it might affect you. If you're worried about changes in your weight, it's a good idea to talk to your healthcare provider.

Other side effects can include:

• blurred vision
• headache
• abnormal movements, muscle stiffness, trembling and restlessness
• dry mouth
• feeling or being sick
• urinary incontinence (loss of or changes to bladder control, like weeing when you don’t want to).

This list of side effects may seem alarming, and you might not experience all of them; however, it is essential to be aware of any potential side effects, so you know how to respond if they do occur.

Unless your side effects are severe or particularly distressing, try to continue taking your medication until you can consult your doctor. If necessary, your doctor can adjust your medication to help alleviate any issues you may be experiencing.

Clozapine can sometimes make you very sleepy, especially when you first start taking it or when your dose is increased. This side effect often improves over time. As a result, you may go to sleep earlier than usual and find it more difficult to wake up in the morning. 

Depending on your prescribed dose, you can take your medication in the evening or at bedtime to help reduce daytime drowsiness.

If you've been on clozapine for over a month and still feel more tired than usual during the day, it's a good idea to check in with your doctor about some possible changes to your treatment.

Sometimes urgent questions or issues related to clozapine may arise when your doctor or support team is unavailable. In such cases, your local pharmacist can be a good alternative. While they may not be part of your support team and may not be aware of the finer details of your treatment, they can provide general information. However, always refer to your doctor or support team for the most accurate information.

If you forget to take a clozapine dose, take it as soon as you remember unless it is less than four hours until your next scheduled dose. If it is nearly time for your next dose, skip the missed dose. Don't double up and take two doses at once. If you miss taking the medication for more than 48 hours, contact your doctor as you will have to restart at a lower dose.

If you're planning to stop taking clozapine, it's best to do it gradually over approximately 3 months, depending on how long you have been taking it. However, if a blood test results in a low neutrophil count (a type of white blood cell), you may need to stop taking the medication immediately, depending on the level. Your doctor is there to guide you and help with any withdrawal symptoms. Before you stop, make sure you speak with your doctor.

Good planning and support are key when considering stopping the medication. Consider any big events coming up, or if you're going through a tough time, this might not be the best moment to change your medication.

Clozapine isn't addictive, but stopping suddenly can bring on withdrawal symptoms and might worsen your condition.

Withdrawal symptoms usually happen within a few days and can include:

• trouble sleeping,
• low mood or anxiety,
• dizziness,
• headaches,
• difficulty concentrating,
• nausea.

With your doctor's help, you can safely stop clozapine. Based on your treatment history, they'll work with you to gradually lower your dose and come up with a plan.

When you start taking clozapine, it is important to know:

• Some people start clozapine in an inpatient unit (IPU) and are there for around 2 weeks. Circumstances may vary from person to person.
• You will need to undergo regular blood tests.
• You may have heart tests, such as an electrocardiogram (ECG) and an echocardiogram (ultrasound), to evaluate your heart health.
• You will have your pulse, blood pressure, and temperature closely monitored.

Regular blood tests are necessary while you are on clozapine. Initially, these tests are conducted every week. After 18 weeks of treatment, the frequency is reduced to once every four weeks. These blood tests are vital because clozapine can sometimes cause a rare side effect known as neutropenia or agranulocytosis. Less than 0.5% of patients taking clozapine may develop agranulocytosis. This condition affects your white blood cells, which are crucial for fighting infections. Monitoring your white blood cell count helps ensure your safety while taking clozapine.

Smoking

Let your doctor know if you change your smoking habits because this can affect how much clozapine you need. If you smoke, you might need a higher dose, or if you switch to vaping or decide to quit, it could increase the risk of side effects.

Alcohol 

Combining alcohol with clozapine can increase feelings of drowsiness and unsteadiness, particularly when you first start taking the medication. While on clozapine, it can be challenging to predict how strongly alcohol will affect you. 

Substance use   

Clozapine blocks the effects of dopamine, which may result in a weaker "high" from substances than you have experienced before. Increasing the dose of substances to try to achieve a stronger effect is extremely dangerous and can lead to serious health consequences. 

Caffeine and caffeinated drinks 

Consuming a lot of coffee, cola drinks, or other caffeinated drinks can increase your clozapine levels, which isn't safe. If you suddenly cut back on caffeine, it might drop your clozapine levels too much. It's important to talk to your doctor before making any big changes to what you normally drink. 

Most people can drive normally while taking clozapine.

When you start taking clozapine or if your dose increases, you may feel sleepy or dizzy during the first few days or weeks. It's advised to avoid driving or riding a bike during this time until you understand how the medication affects you and until your dose is stabilised.

Please talk to your doctor or pharmacist if you have any concerns or questions.

Most people continue to play sports and exercise as normal while taking clozapine. However, it is important to take some time to see how it may impact you in the first few days or weeks of taking it.

For example, initially, it may cause you to feel tired and dizzy or affect your eyesight. This could be dangerous in some sports, so assess how you are feeling and whether or not you can participate in them for the first few days or weeks of taking the medication.

If you are worried that taking clozapine might make doing the sports you enjoy more difficult, discuss this with your doctor.

Most people can complete exams or study normally while taking clozapine.

Consider the timing of starting the medication, as when you first take clozapine, you may feel tired, dizzy and restless. You should talk to your doctor about any future exams or commitments if you are starting clozapine, and formulate a plan based on their advice.

Clozapine may also improve your motivation and ability to study if timed correctly.

Clozapine may affect your sex drive, leading to changes in sexual desire or function. This is uncommon. If changes in sex drive are impacting your quality of life or relationships, speak with your doctor.

Clozapine can help you recover and has positive effects, including improving your desire for, experience with, and enjoyment of intimate relationships again.

Fertility

From the limited studies available, there is currently no evidence to suggest that clozapine has any direct effect on fertility.

Talk to your doctor about your clozapine if you are trying to get pregnant or planning a family.

If you are planning on becoming pregnant, notify your healthcare provider to manage your medications best. Discussing the risks and benefits of treatment with your doctor is important.

Clozapine can make you feel drowsy, affecting social activities like going out with friends or partying at night. Consider taking clozapine at a different time, planning social events earlier in the day or switching to non-alcoholic drinks.

One young person's description of how they socialised with friends while taking clozapine.

“My friends and I would socialise in different ways to make sure it worked for everyone. Sometimes, some of us stayed in while others went out so we could all have fun, and I wasn’t left out when I felt tired from my medication. We talked openly about what we wanted to do, and my medication was just part of that conversation.

Always inform your pharmacist about any food allergies or intolerances you may have.

The tablets could contain lactose, which means they might not be appropriate for you if you have difficulties digesting certain sugars or dairy items.

Several companies produce clozapine, but you will typically be given the same brand. If there is ever a change, it’s important to consult with your pharmacist if you have any concerns about the ingredients in your medication.

If you want to steer clear of animal products, keep in mind that some inactive ingredients found in medications could come from animal sources. Don’t hesitate to consult your pharmacist if you have any inquiries regarding the ingredients.

For additional details regarding the practical aspects of medications for those who wish to avoid animal products, you can visit the Vegan Society website.

Before starting clozapine, inform your doctor or pharmacist about all other prescription and over-the-counter medications you're using, including any topical creams or ointments.

Some medications can change how your body processes clozapine, which might lead to higher or lower levels of the drug in your system. If you start or stop using combined hormonal contraceptives, they can raise the amount of clozapine in your body, so your doctor may need to check and adjust your dose.

Be careful with any medications that can cause constipation, like codeine. This can be a serious side effect when taking clozapine.

If you're taking other sedating medications along with clozapine, it can make you feel extra tired, and this might affect your ability to drive or ride a bike safely.

For more information about potential interactions with clozapine, refer to the leaflet inside your medicine box. If you're taking other medications, your doctor might need to adjust your clozapine dose. If you have any questions, please don't hesitate to ask your doctor or pharmacist.

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

It is also important to know that you do not have to tell others about the name of the medication or why you are taking it. 

There are various ways to initiate this conversation. Below are some example sentences you can use to start the conversation 

Starting Clozapine 

Person A: I just wanted to mention that I've started a new medication. While I'm getting used to it, I might end up feeling tired or have some different side effects. 

Person B: What's the medication for? 

Person A: It's for some health stuff I'm currently dealing with. I figured I should let you know because I might be tired when we hang out and could need to take a break. I also might not be able to drive. 

What's the medication for?       

Example sentence: I just wanted to mention that I've started a new medication. While I'm getting used to it, I might end up feeling more tired or have some different side effects that you may notice. 

Asking for Help (School and Work) 

Example sentence: I've started this new medication, and I'm feeling super tired and a bit out of it, so I'm having trouble concentrating. I need to take a break. 

Asking for Help (Medical) 

Example sentence: I'm feeling really unwell, and I think it might be because of the new medication. Can you help me contact my doctor or call an ambulance? 

Your family can be a great source of support. They may also feel uncertain about starting clozapine, and this is okay!

Stigma can increase the isolation faced by those experiencing psychosis. As a loved one, you can play a powerful role in challenging these misconceptions. Talking openly, providing facts, and sharing your experience can promote empathy and understanding. By doing this, you're supporting your loved one and promoting a more accepting society.

Peer support is available! Peer support is when people give or receive support based on shared experiences of mental health concerns.

• Peer work: If you are seeking additional information and resources about peer support you can find more information here.

• Hearing Voices (Peer Support Group): Hearing Voices is a mental health-based support group. The organisation is based on self-help, mutual respect, empathy, social support, and belonging rather than therapy or treatment. It also offers an opportunity for people to accept and live with their experiences in a way that helps them regain some power over their lives.

• @psychosis_understood: An Instagram community made by young people who have experienced psychosis, teaming up with researchers to share tips, stories, and resources about psychosis.

• Clozapine tends to lead to weight gain. Consistent exercise and a healthy diet are good ways to manage this side effect. An example of a balanced diet is fruits, vegetables, whole grains, and lean protein. Limiting unhealthy foods and reducing intake of sugary drinks, processed foods, and unhealthy fats are also important. One way to manage this is to eat homemade meals and practice portion control. Consistent exercise could include:
• Regular physical activity, aiming for at least 150 minutes of moderate-intensity aerobic exercise per week. This can be achieved by incorporating a variety of activities, such as walking, jogging, swimming, or cycling, to stay active.
• Increasing the number of steps you take in a day is also a good way to be active.
• Strength training exercises to help build muscle mass and improve metabolism.

When you arrive at an inpatient unit, the staff will provide you with an orientation of the unit. A doctor will meet you and begin your introduction to the unit.

During your time in the IPU, the hospital staff will work with your community GP, chosen carers or family, and other hospital staff to answer questions and discuss treatment and follow-up care.

Often, peer workers work within the IPU and can provide emotional support and resources to help you during this time. Please speak to a member of staff to be referred to a peer worker.

A peer worker is someone with lived experience of mental health challenges who provides support. They are there to help you during your time in the IPU and can connect you with resources that may be helpful.

Some things you may want to bring with you:

• Medicare Card, don't forget this!
• Health Care Card / Concession Card
• List of medications: Jot down any medications you're on, including over-the-counter items like vitamins and herbal supplements.
• Comfy clothes and shoes: You'll want something easy to move around in.
• Personal hygiene products include items such as shampoo, shaving cream, toothpaste, and deodorant. These items can also be supplied if needed.
• Quiet activities, bring along something you enjoy, like a book, journal, or tablet for music, movies, or podcasts.

It is advisable not to bring valuables, such as jewellery or watches.

Agranulocytosis

Agranulocytosis (caused by extreme neutropenia) is a rare side effect of taking clozapine and a serious health condition where your body has low levels of a type of white blood cell called neutrophils. These cells are important because they help your immune system fight infections. Without enough neutrophils, your body struggles to defend itself against germs, which can make you sick. Less than 0.5% of patients taking clozapine may develop a condition called agranulocytosis.

Neutropenia

Any deficiency in neutrophil count - an exceptionally low neutrophil count causes agranulocytosis.

Neutrophil

 A type of white blood cell

White blood cells

A crucial part of the immune system protects the body from infections and other diseases.

Antipsychotics

Are a type of drug that is primarily used to manage psychosis.

Clozapine clinics

Clinics that provide specialised care and management for individuals taking clozapine. Nurses and psychiatrists often run them. These clinics team up with general practitioners (GPs) to monitor patients closely, check blood tests, and ensure the treatment goes smoothly.

Myocarditis

Heart muscle inflammation and cardiomyopathy (enlarged heart). These side effects have been rarely reported, but it is a condition that could be fatal. Symptoms of these heart problems include shortness of breath, a racing heart, flu-like symptoms, or chest pain. Contact your healthcare provider right away if these symptoms occur.

Neurotransmitters

 Chemical messages that help nerve cells (neurons) communicate with each other and connect with other cells in the body.

Ultrasound

 An ultrasound test uses sound waves to create images of your organs, tissues, and other structures inside your body.

ECG

An electrocardiogram (ECG) acts like a detailed map of your heart's electrical activity, showing how fast and how regularly the heart is beating. This safe and painless test uses small stickers (electrodes) on your chest and arms to detect the heart's electrical signals. 

An inpatient unit (IPU)

 Where someone who needs a hospital stay for mental health reasons will be admitted.