Denzapine Side Effects

Generic name: clozapine

Medically reviewed by Drugs.com. Last updated on Nov 19, 2024.

Note: This document provides detailed information about Denzapine Side Effects associated with clozapine. Some dosage forms listed on this page may not apply specifically to the brand name Denzapine.

Applies to clozapine: oral suspension, oral tablet, oral tablet disintegrating.

Precautions

Clozapine can cause some very serious blood problems that you will not be able to feel. Your doctor will check your blood at regular visits and it is important that you have your blood tests done when they are scheduled. The pharmacy will give you this medicine only if your blood tests show that it is safe for you to take it. Your doctor will make sure the medicine is working properly and change the dosage if needed.

Clozapine can temporarily lower the number of white blood cells in your blood, increasing the chance of getting an infection. If you can, avoid people with infections. Check with your doctor right away if you think you are getting an infection, or if you have a fever or chills, cough or hoarseness, lower back or side pain, or painful or difficult urination.

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

Clozapine may cause drowsiness, blurred vision, convulsions (seizures), or to have trouble with thinking or controlling body movements, which may lead to falls, fractures or other injuries. Do not drive, operate machines, swimming, climbing, or do anything else that could be dangerous until you know how this medicine affects you.

This medicine can cause changes in your heart rhythm, such as a condition called QT prolongation. It may cause fainting or serious side effects in some patients. Contact your doctor right away if you have fast, pounding, or uneven heartbeats.

Dizziness, lightheadedness, or fainting may occur, especially when you get up from a lying or sitting position suddenly. These symptoms are more likely to occur when you begin taking this medicine, or when the dose is increased. Getting up slowly may help. If this problem continues or gets worse, check with your doctor.

Clozapine may cause stomach or bowel problems (eg, gastrointestinal hypomotility). Tell your doctor right away if you have severe constipation, nausea, vomiting, or stomach pain or swelling.

This medicine may increase your risk for anticholinergic effects, especially when used with other medicines (eg, benztropine, cyclobenzaprine, or diphenhydramine). Check with doctor right away if you have blurred vision, dizziness, drowsiness, confusion, delirium, or hallucinations, nausea, vomiting, constipation, difficult urination, eye pain, dry eyes, mouth, nose, or throat, flushing or redness of the face, troubled breathing, or fast heartbeat.

This medicine may cause serious skin reaction, including drug reaction with eosinophilia and systemic symptoms. Check with your doctor right away if you have black, tarry stools, chest pain, chills, cough, fever, painful or difficult urination, sore throat, sores, ulcers, or white spots in the mouth or on the lips, swollen glands, trouble breathing, unusual bleeding or bruising, or unusual tiredness or weakness.

For diabetic patients: This medicine may increase the amount of sugar in your blood. Check with your doctor right away if you have increased thirst or urination. Diabetic patients should check their blood and urine sugar levels more often than normal while taking this medicine.

In some patients, clozapine (the active ingredient contained in Denzapine) may cause increased watering of the mouth. Other patients, however, may get dryness of the mouth. For temporary relief of mouth dryness, use sugarless gum or candy, melt bits of ice in your mouth, or use a saliva substitute. However, if your mouth continues to feel dry for more than 2 weeks, check with your medical doctor or dentist. Continuing dryness of the mouth may increase the chance of dental disease, including tooth decay, gum disease, and fungus infections.

Check with your doctor right away if you are having convulsions (seizures), difficulty with breathing, fast heartbeat, high fever, high or low blood pressure, increased sweating, loss of bladder control, severe muscle stiffness, unusually pale skin, or tiredness. These could be symptoms of a serious condition called neuroleptic malignant syndrome (NMS).

This medicine may cause tardive dyskinesia (a movement disorder) among the elderly, especially elderly women. Check with your doctor right away if you have any of the following symptoms while taking this medicine: lip smacking or puckering, puffing of the cheeks, rapid or worm-like movements of the tongue, uncontrolled chewing movements, or uncontrolled movements of the arms and legs.

Check with your doctor right away if you have pain or tenderness in the upper stomach, pale stools, dark urine, loss of appetite, nausea, unusual tiredness or weakness, or yellow eyes or skin. These could be symptoms of a serious liver problem.

If you have been using this medicine regularly, do not stop taking it without first checking with your doctor. Your doctor may want you to gradually reduce the amount you are taking before stopping it completely. This is to help prevent the illness from suddenly returning and to decrease the chance of having symptoms such as headache, nausea, vomiting or diarrhea.

Check with your doctor right away if you have anxiety, chest pain, cough, dizziness or lightheadedness, fainting, fast heartbeat, pain, redness, or swelling in the arm or leg, or sudden trouble breathing. These maybe symptoms of serious blood clotting problems (eg, pulmonary embolism and deep vein thrombosis).

This medicine will add to the effects of alcohol and other central nervous system (CNS) depressants, which are medicines that slow down the nervous system and possibly cause drowsiness. Some examples of CNS depressants are antihistamines or medicine for hay fever, other allergies, or colds, sedatives, tranquilizers, or sleeping medicine, prescription pain medicine or narcotics, medicine for seizures or barbiturates, muscle relaxants, or anesthetics, including some dental anesthetics. Check with your doctor before taking any of the above while you are using this medicine.

Make sure any doctor or dentist who treats you knows that you are using this medicine. You may need to stop using this medicine several days before having surgery or medical tests.

Tell your doctor if you smoke or drink products that contain caffeine.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal (eg, St. John's wort) or vitamin supplements.

Serious side effects of Denzapine

Along with its needed effects, clozapine may cause some unwanted effects. 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 while taking clozapine:

Other side effects of Denzapine

Some side effects of clozapine 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:

For healthcare professionals

Applies to clozapine: oral suspension, oral tablet, oral tablet disintegrating.

General adverse events

The most commonly reported side effects included salivary hypersecretion, somnolence, and weight gain.^[Ref]

Gastrointestinal

• Very common (10% or more): Salivary hypersecretion/hypersalivation (up to 48%), salivation (up to 31%), constipation (up to 25%), nausea (up to 17%), vomiting (up to 17%), dyspepsia (up to 14%)
• Common (1% to 10%): Abdominal discomfort/dyspepsia/heartburn, diarrhea, dry mouth
• Rare (0.01% to 0.1%): Acute pancreatitis, Dysphagia, ileus impaction, pancreatitis
• Very rare (less than 0.01%): Fecal impaction/intestinal obstruction/paralytic ileus, parotid gland enlargement
• Frequency not reported: Colitis, swallowing difficulty, tongue protrusion
• Postmarketing reports: Intestinal infarction/ischemia/fatal intestinal infarction/ischemia, megacolon/fatal megacolon, salivary gland swelling^[Ref]

Nervous system

• Very common (10% or more): Somnolence (up to 46%), drowsiness/sedation (up to 39%), dizziness (up to 27%), vertigo (up to 19%), headache (up to 10%)
• Common (1% to 10%): Akathisia, akinesia, convulsions/myoclonic jerks/seizures, dysarthria, extrapyramidal symptoms, hypokinesia, syncope, tremor
• Uncommon (0.1% to 1%): Neuroleptic malignant syndrome
• Very rare (less than 0.01%): Tardive dyskinesia
• Frequency not reported: Dystonia
• Postmarketing reports: Abnormal EEG, cholinergic syndrome, clozapine-induced seizures, EEG changes, motor instability, myasthenic syndrome, myoclonus, paresthesia, pleurothotonus, possible cataplexy, post-discontinuation cholinergic rebound adverse reactions, sensory instability, status epilepticus^[Ref]

The cumulative incidence of seizure at 1 year is approximately 5% based on pre-marketing testing. The risk is dose-related.

Extrapyramidal symptoms that occur appear to be milder and less frequent than other antipsychotic drugs. There have been no reports of tardive dyskinesia directly attributable to clozapine (the active ingredient contained in Denzapine) however, the syndrome has been reported in a few patients who were treated with other antipsychotics prior to receiving clozapine. A causal relationship can neither be established nor excluded.

Cholinergic syndrome occurred after abrupt withdrawal.^[Ref]

Metabolic

• Very common (10% or more): Increased weight/weight gain (up to 31%)
• Common (1% to 10%): Anorexia
• Rare (0.01% to 0.1%): Aggravated diabetes, diabetes mellitus, hyperosmolar coma, impaired glucose tolerance, ketoacidosis, severe hyperglycemia
• Very rare (less than 0.01%): Hypercholesterolemia, hypertriglyceridemia
• Frequency not reported: Pseudopheochromocytoma
• Postmarketing reports: Hypernatremia, hyperuricemia, obesity, weight loss^[Ref]

Diabetes mellitus occurred in patients without a history of hyperglycemia or diabetes mellitus.

Pooled data from 8 studies in patients with schizophrenia found the mean change in fasting blood glucose in clozapine (the active ingredient contained in Denzapine) treated patients was +11 mg/dL; pooled data from 10 studies revealed clozapine treatment was associated a mean increase of 13 mg/dl in total cholesterol; pooled data from 11 studies showed a weight gain of 7% or greater relative to baseline body weight occurred in 35% of patients with a mean weight gain of 3.7 kg.^[Ref]

Cardiovascular

• Very common (10% or more): Tachycardia (up to 25%), hypotension (up to 13%), hypertension (up to 12%)
• Common (1% to 10%): ECG changes, postural hypotension
• Rare (0.01% to 0.1%): Arrhythmias, circulatory collapse, myocarditis, pericardial effusion, pericarditis, thromboembolism, ventricular arrhythmia, ventricular fibrillation, ventricular tachycardia
• Very rare (less than 0.01%): Cardiac arrest, cardiomyopathy/clozapine-related cardiomyopathy, QT prolongation, skin reactions, Torsade de pointes
• Frequency not reported: Angina pectoris/chest pain, myocardial infarction/fatal myocardial infarction, pigmentation disorder, venous thromboembolism
• Postmarketing reports: Atrial fibrillation, deep vein thrombosis, mitral valve incompetence, palpitations^[Ref]

Isolated cases of cardiac arrhythmias, pericarditis/pericardial effusion, and myocarditis have been reported. Postmarketing, very rare events of ventricular tachycardia, cardiac arrest, and QT prolongation which may be associated with Torsades de pointes have been observed, although there is no conclusive causal relationship to use of this drug.^[Ref]

Psychiatric

• Very common (10% or more): Insomnia (up to 20%)
• Common (1% to 10%): Agitation, confusion, disturbed sleep/nightmares, restlessness
• Uncommon (0.1% to 1%): Dysphemia
• Rare (0.01% to 0.1%): Delirium, dream activity intensification
• Very rare (less than 0.01%): Obsessive compulsive disorder/symptoms
• Frequency not reported: Neonatal drug withdrawal syndrome^[Ref]

Other

• Very common (10% or more): Fever/hyperthermia (up to 13%)
• Common (1% to 10%): Benign hyperthermia, fatigue, temperature regulation disturbance
• Very rare (less than 0.01%): Sudden unexplained death
• Postmarketing reports: Falls, polyserositis, sepsis^[Ref]

Hematologic

• Common (1% to 10%): Decreased white blood cells, eosinophilia, leukocytosis, leukopenia, neutropenia
• Uncommon (0.1% to 1%): Agranulocytosis
• Rare (0.01% to 0.1%): Anemia
• Very rare (less than 0.01%): Thrombocythemia, thrombocytopenia
• Postmarketing reports: Elevated hematocrit, elevated hemoglobin, granulocytopenia, increased erythrocyte sedimentation rate, mild leukopenia, moderate leukopenia, severe leukopenia, thrombocytosis^[Ref]

During pre-marketing testing, the cumulative incidence of agranulocytosis at one year was reported to be 1.3%. Based on Clozaril National Registry (US patients) data collected up to April 1995, a hematologic risk analysis found the incidence of agranulocytosis rises steeply during the first 2 months, peaks at approximately the third month, and decreases at 6 months of therapy; after 6 months, the incidence decreases further, however, it never reaches zero. Individuals with an initial episode of moderate leukopenia (WBC of at least 2000/mm3 and less than 3000/mm3) are at an increased risk of having a subsequent episode of agranulocytosis.

In the UK, agranulocytosis occurred within the first 18 weeks in approximately 70% of patients who developed the condition.

In clinical trials, eosinophil counts of greater than 700/mm3 occurred in approximately 1% of patients. Eosinophilia has been co-reported with some cases of myocarditis (approximately 14%) and pericarditis/pericardial effusion, although it is unknown whether eosinophilia is a reliable predictor of carditis.^[Ref]

Genitourinary

• Common (1% to 10%): Urinary abnormalities, urinary incontinence, urinary retention
• Very rare (less than 0.01%): Dysmenorrhea, ejaculation change, impotence, priapism
• Postmarketing reports: Nocturnal enuresis, retrograde ejaculation^[Ref]

Dermatologic

• Common (1% to 10%): Rash, sweating/sweating disturbance
• Frequency not reported: Leukocytoclastic vasculitis
• Postmarketing reports: Erythema multiforme, photosensitivity, skin pigmentation disorder, Stevens-Johnson syndrome^[Ref]

Ocular

• Common (1% to 10%): Blurred vision, visual disturbances
• Postmarketing reports: Narrow angle glaucoma, periorbital edema^[Ref]

Hepatic

• Common (1% to 10%): Elevated liver enzymes
• Rare (0.01% to 0.1%): Cholestasis, cholestatic jaundice, hepatitis
• Very rare (less than 0.01%): Fulminant hepatic necrosis
• Postmarketing reports: Cholestatic injury, hepatic cirrhosis, hepatic fibrosis, hepatic injury, hepatic necrosis, hepatic steatosis, hepatotoxicity, jaundice, liver failure, liver transplant, mixed injury^[Ref]

Musculoskeletal

• Common (1% to 10%): Rigidity
• Rare (0.01% to 0.1%): Creatine phosphokinase elevation
• Frequency not reported: Muscle pain, muscle spasms, muscle weakness, neck muscle spasm, systemic lupus erythematosus
• Postmarketing reports: Rhabdomyolysis^[Ref]

Respiratory

• Rare (0.01% to 0.1%): Aspiration of ingested food, lower respiratory tract infection/fatal lower respiratory tract infection, pneumonia, pulmonary embolism, respiratory arrest, respiratory depression, respiratory depression/arrest with/without circulatory collapse
• Very rare (less than 0.01%): Allergic asthma
• Frequency not reported: Difficulty breathing, nasal congestion, throat tightness
• Postmarketing reports: Pleural effusion, sleep apnea/sleep apnea syndrome^[Ref]

Aspiration of ingested food usually occurred in patients with dysphagia or in acute overdose.^[Ref]

Renal

• Very rare (less than 0.01%): Acute interstitial nephritis/interstitial nephritis
• Postmarketing reports: Renal failure^[Ref]

Hypersensitivity

• Frequency not reported: Angioedema
• Postmarketing reports: hypersensitivity reactions^[Ref]

Endocrine

• Postmarketing reports: Pseudopheochromocytoma^[Ref]

See also:

Further information

Denzapine side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

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