Clozapine (Oral Route)

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Side Effects

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 or two for as long as you are taking clozapine and for 4 weeks after you stop taking it. Although not all of these side effects may occur, if they do occur they may need medical attention.

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

• Blurred vision
• Confusion
• Dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
• Fainting
• Fast, pounding, or irregular heartbeat or pulse
• Fever
• Low blood pressure
• Shakiness in the legs, arms, hands, or feet
• Sleepiness or unusual drowsiness
• Sweating
• Trembling or shaking of the hands or feet
• Unusual tiredness or weakness

• Anxiety
• Black, tarry stools
• Chest pain
• Chills
• Convulsions
• Cough or hoarseness
• Decrease in frequency of urination
• Decrease in urine volume
• Difficult or labored breathing
• Difficulty in passing urine (dribbling)
• Discouragement
• Dry mouth
• Fear or nervousness
• Feeling sad or empty
• Fever with or without chills
• Frequent strong or increased urge to urinate
• General feeling of tiredness or weakness
• Headache
• Hyperventilation
• Irritability
• Lack of appetite
• Loss of bladder control
• Loss of interest or pleasure
• Lower back or side pain
• Mood or mental changes
• Muscle spasm or jerking of all extremities
• Painful or difficult urination
• Pounding in the ears
• Restlessness or need to keep moving
• Severe or continuing headache
• Shakiness and unsteady walk
• Shortness of breath
• Slurred speech
• Sore throat
• Sores, ulcers, or white spots on the lips or in the mouth
• Sudden jerky movements of the body
• Sudden loss of consciousness
• Swollen glands
• Throat discomfort
• Tightness in the chest
• Trouble concentrating
• Trouble sleeping
• Unsteadiness, trembling, or other problems with muscle control or coordination
• Wheezing

• Absence of or decrease in movement
• Dark urine
• Decreased appetite
• Decreased sexual ability
• Difficult or fast breathing or sudden shortness of breath
• Increased appetite
• Increased sweating
• Increased thirst
• Increased urination
• Lip smacking or puckering
• Loss of bladder control
• Mental depression
• Muscle stiffness (severe)
• Nausea
• Puffing of the cheeks
• Rapid or worm-like movements of the tongue
• Swelling or pain in the leg
• Trouble breathing
• Trouble in urinating
• Uncontrolled chewing movements
• Uncontrolled movements of the arms and legs
• Unusual bleeding or bruising
• Unusually pale skin
• Vomiting
• Weakness
• Yellow eyes or skin

• Abdominal or stomach pain
• Bloating
• Burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
• Clay-colored stools
• Confusion as to time, place, or person
• Constipation
• Darkened urine
• Diarrhea
• Epileptic seizure that will not stop
• Feeling that others are watching you or controlling your behavior
• Feeling that others can hear your thoughts
• Feeling, seeing, or hearing things that are not there
• Holding false beliefs that cannot be changed by fact
• Inability to move the eyes
• Increased blinking or spasms of the eyelid
• Indigestion
• Itching
• Joint pain
• Light-colored stools
• Muscle twitching
• Pains in the stomach, side, or abdomen, possibly radiating to the back
• Rhythmic movement of the muscles
• Severe mood or mental changes
• Skin rash
• Sticking out of the tongue
• Swelling around the eyes
• Swelling of the body or feet and ankles
• Trouble in breathing, speaking, or swallowing
• Uncontrolled twisting movements of the neck, trunk, arms, or legs
• Unpleasant breath odor
• Unusual behavior
• Unusual excitement, nervousness, or restlessness
• Unusual facial expressions
• Unusual weight gain
• Upper right abdominal or stomach pain
• Vomiting of blood
• Yellow eyes or skin

Get emergency help immediately if any of the following symptoms of overdose occur:

• Change in consciousness
• Drowsiness
• Increased watering of mouth (severe)
• Irregular, fast or slow, or shallow breathing
• Loss of consciousness
• Pale or blue lips, fingernails, or skin
• Pounding or rapid pulse

Some 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. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

• Acid or sour stomach
• Belching
• Feeling of constant movement of self or surroundings
• Heartburn
• Relaxed and calm sensation of spinning
• Sleepiness
• Sleeplessness
• Unable to sleep

• Blurred or loss of vision
• Change or problem with discharge of semen
• Disturbed color perception
• Double vision
• Halos around lights
• Inability to sit still
• Increase in body movements
• Muscle pain or ache
• Muscle weakness
• Night blindness
• Nightmares
• Overbright appearance of lights
• Pain in the back, neck, or legs
• Pain in the chest below the breastbone
• Severe muscle stiffness
• Sore tongue
• Stuffy nose
• Tunnel vision
• Unusual drowsiness, dullness, tiredness, weakness, or feeling of sluggishness

• Blistering, peeling, or loosening of the skin
• Difficulty with swallowing
• Hives
• Increased sensitivity of the skin to sunlight
• Painful or prolonged erection of the penis
• Red skin lesions, often with a purple center
• Red, irritated eyes
• Reddening of the skin, especially around the ears
• Severe stomach pain
• Severe sunburn
• Sores, welting, or blisters
• Swelling of the eyes, face, or inside of the nose
• Swelling of the salivary glands

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

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