Clozapine

Why have I been prescribed Clozapine?
Clozapine is an antipsychotic, used to treat schizophrenia. It is often effective where other antipsychotics have not helped or one had to stop them due to serious side effects. In schizophrenia, many people hear voices of people talking to them or about them. They may also become suspicious or paranoid. Some people have problems with their thinking and feel that other people can read their thoughts. These are usually called “positive” symptoms. Many people with schizophrenia also experience “negative symptoms”. They feel tired and lacking in energy and can become quite inactive and withdrawn. Clozapine can help both positive and negative symptoms.

What exactly is Clozapine?
Clozapine is an antipsychotic. Sometimes it is also known as an atypical or newer generation antipsychotic, because it tends not to cause some of the side effects that older generation antipsychotics do (like shaking and other strange movements). Clozapine works in a different way and has other side effects. The brand or trade name of Clozapine, available in India is Sizopin, Skizoril, Lozapine, Chrozep among others.

Is clozapine safe to take?
Before the patients start taking Clozapine, their blood has to be tested, and they will continue to have regular blood tests. This is because, very rarely, Clozapine can lower the number of white cells in the blood. White cells are very important in the blood as they fight infection. If you have too few white cells, it will be harder for your body to fight off cells in your blood. Only one or two in every hundred have this bad reaction. It is not related to the dose of Clozapine that you are taking. If your blood shows that your white cells are falling down, then Clozapine is stopped.
It is usually safe to have Clozapine regularly as prescribed by your psychiatrist, but it doesn’t suit everyone. You should always tell your doctor if you have:

• Epilepsy or glaucoma, or suffer from liver, heart, kidney or prostrate trouble
• If you are taking any other medication, especially antidepressants, or anti convulsants
• If you are taking medication from the pharmacy for colds or ulcers, especially antihistamines or cimetidine (Tagamet)
• If you are pregnant, breast feeding, or wish to become pregnant

What is the usual dose of clozapine?
The starting dose is usually 12.5mg per day, which is increased slowly over a few weeks. The usual dose can be anything 300mg and 600mg a day, with the maximum dose being 900mg a day.

What should I do if I miss a dose?
If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses. If you miss 2 or more days of clozapine doses, talk to your doctor before you start taking it again. You may need to restart this medicine at a lower dose than you were taking before.

How long will it take before I can see it work?
Clozapine does not work straight away. It may take several days or even weeks for some of the symptoms to reduce. To begin with, many people find that this medication will help them feel more relaxed and calm. Later, after two or three weeks, other symptoms should begin to improve. Unfortunately, you might get some side effects before you start to feel any better. Most side effects should go away after a few weeks.

Are there any side effects of taking clozapine?
Along with its needed effects, a medicine may cause some unwanted effects. Some side effects may not have signs or symptoms that you can see or feel. Clozapine can cause some very serious blood problems. Your doctor will watch for these by doing blood tests every week for 18 weeks, every two weeks for another 18 weeks and then every four weeks for as long as you are taking clozapine and for 4 weeks after you stop taking it. Please note that not all patients will get all the side effects listed. There may be possibly other side effects. Always consult your psychiatrist about the side effects.

The most serious adverse reactions experienced with clozapine are agranulocytosis (lowering of white cell count in the blood), seizure, cardiovascular effects and fever. The most common side effects are drowsiness, excessive salivation, tachycardia and sedation.

Contact your doctor as soon as possible if you develop unusual tiredness or weakness, fever, sore throat, or other symptoms of infection. These can be symptoms of a very serious blood problem.

Contact your doctor as soon as possible if you have chest pain or discomfort, a fast heartbeat, trouble breathing, or fever and chills. These can be symptoms of a very serious problem with your heart.

Check with your doctor immediately if any of the following side effects occur:

More common
   Fast or irregular heartbeat; fever; low blood pressure
   
Less common
   High blood pressure (severe or continuing headache)
   
Rare
   Chest pain or discomfort; chills; convulsions (seizures); cough; difficult or fast breathing or sudden shortness of breath; fainting; increased sweating;    
   loss of bladder control; muscle stiffness (severe); sore throat; sores, ulcers, or white spots on lips or in mouth; swelling or pain in leg; trouble breathing;   
   unusual bleeding or bruising or any other change in blood count, and any unusual tiredness or weakness; unusually pale skin

Check with your doctor as soon as possible if any of the following side effects occur:
   
More common
   Dizziness, especially when getting up from a lying or sitting position
   
Less common
   Blurred vision; confusion; restlessness or need to keep moving; unusual anxiety, nervousness, or irritability
   
Rare
   Absence of or decrease in movement; decreased sexual ability; high blood sugar    (increased appetite, increased thirst, increased urination, weakness);
   lip smacking or puckering; liver problems (dark urine, decreased appetite, nausea, vomiting, yellow eyes or skin); mental depression; puffing of cheeks; rapid or 
   worm-like movements of tongue; trembling or shaking; trouble in sleeping; trouble in urinating; uncontrolled chewing movements; uncontrolled movements of arms 
   and legs

Symptoms of overdose
   Convulsions (seizures); dizziness or fainting; drowsiness (severe) or coma; fast, slow, or irregular heartbeat; hallucinations (seeing, hearing, or feeling    
   things that are not there); increased watering of mouth (severe); slow, irregular, or troubled breathing; unusual excitement, nervousness, or restlessness
  
   Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine.   
  However, check with your doctor if any of the following side effects continue    or are bothersome:
   
More common
   Constipation; dizziness or light headedness (mild); drowsiness; headache (mild);    increased watering of mouth; nausea or vomiting; unusual weight gain
   
Less common
   Abdominal discomfort or heartburn; dryness of mouth

Will clozapine interact with any other medication I am taking?
   Some medications may interact with clozapine while they are being metabolised in the body. It is always safer to inform your psychiatrist about any other    
  drugs you may be taking, especially if you are taking antidepressant medication, anti convulsants to control seizures/epilepsy, lithium or if you are taking    
  medication from the pharmacy for colds or ulcers, especially antihistamines    or cimetidine (Tagamet)

What about alcohol?
It is officially recommended that people taking clozapine should not drink alcohol. This is because both alcohol and clozapine can cause drowsiness, which can lead to falls or accidents. Alcohol can also make your psychosis worse.

What about driving?
For the above reasons of drowsiness, it is safer you do not drive while you are taking clozapine.

When I feel better, can I stop the medication?
No. If you stop taking clozapine, your original symptoms may return, although sometimes it may not happen until 2-3 months after you stop clozapine. You and your psychiatrist should decide together when you can stop your medication. Most people need to be on clozapine for a long time, even several years. If you need to stop it, it should be done gradually unless it is urgent that it be stopped abruptly.
For more information on clozapine, click on the following links: