How does this medication work? What will it do for me?

Chlorpromazine belongs to the class of medications known as phenothiazines. It is used to treat mania and disorders with psychosis, such as schizophrenia. It is also used to prevent and treat nausea and vomiting. Chlorpromazine works by affecting the balance of chemicals in the brain.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are being given this medication, speak to your doctor. Do not stop using this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to use this medication if their doctor has not prescribed it.

What form(s) does this medication come in?

Chlorpromazine HCl Injection is no longer being manufactured for sale in Canada. For brands that may still be available, search under chlorpromazine. This article is being kept available for reference purposes only. If you are using this medication, speak with your doctor or pharmacist for information about your treatment options.

How should I use this medication?

The recommended dose of chlorpromazine for psychosis varies from 25 mg to 75 mg daily divided into 2 to 4 doses. It may take some time (weeks or months) to show the full effect of this medication. The usual maximum recommended daily dose of chlorpromazine is 1,000 mg.

To relieve nausea and vomiting, the recommended dose of chlorpromazine is 12.5 mg to 25 mg every 4 hours. The maximum daily dose is 150 mg per day.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are using the medication without consulting your doctor.

It is important to use this medication exactly as prescribed by your doctor. If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, protect it from light, and keep it out of the reach of children.

Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.

Who should NOT take this medication?

Chlorpromazine should not be used by anyone who:

  • is allergic to chlorpromazine or to any of the ingredients of the medication
  • is allergic to other phenothiazines
  • is in a coma
  • has a blood disorder
  • has brain damage
  • has decreased functioning of bone marrow
  • has severely decreased functioning of the central nervous system (e.g., brain, spinal cord) due to taking certain medications
  • has severely decreased liver function

What side effects are possible with this medication?

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent. The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

  • agitation
  • constipation
  • decreased interest in sexual activity
  • dizziness
  • drowsiness
  • dry mouth or dry eyes
  • headache
  • increased sweating
  • nasal congestion
  • nausea or vomiting
  • skin sensitivity to the sun
  • trouble sleeping
  • weight gain

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

  • breast swelling
  • confusion
  • difficulty swallowing
  • difficulty urinating
  • fast or irregular heartbeat
  • involuntary movements, mainly of your face or tongue
  • muscle stiffness
  • new or worsening constipation
  • production of breast milk
  • restlessness
  • sexual difficulties
  • signs of liver problems (e.g., nausea, vomiting, diarrhea, loss of appetite, weight loss, yellowing of the skin or whites of the eyes, dark urine, pale stools)
  • skin rash
  • symptoms of blood clots (e.g., swelling, pain, and redness in an arm or leg that can be warm to touch, or sudden chest pain and difficulty breathing)
  • symptoms of increased blood sugar (e.g., feeling very thirsty, feeling very hungry, needing to urinate more than usual, weakness or tiredness, feeling sick to your stomach, confusion, fruity-smelling breath)
  • symptoms of an infection (e.g., sore throat, fever, or weakness, shortness of breath)
  • symptoms of decreased blood pressure (e.g., lightheadedness or fainting when rising too quickly from a sitting or lying position)
  • vision changes

Stop taking the medication and seek immediate medical attention if any of the following occur:

  • long-lasting (greater than 4 hours in duration) and painful erection of the penis
  • seizures
  • signs of an allergic reaction (e.g., shortness of breath or difficulty breathing; fainting; hives; swelling of the eyes, mouth, lips, or throat)
  • signs of neuroleptic malignant syndrome (e.g., pronounced muscle stiffness or inflexibility with high fever, rapid or irregular heartbeat, sweating, confusion, or reduced consciousness)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Are there any other precautions or warnings for this medication?

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Blood cells: Chlorpromazine may lower white blood cell levels in the body. This usually occurs with longer treatment and appears about 4 to 10 weeks after starting treatment. If you have symptoms of an infection (e.g., sore throat, fever, weakness), contact your doctor as soon as possible.

Blood pressure: Chlorpromazine may lower blood pressure leading to dizziness. To help prevent this effect, get up slowly from a sitting position, or dangle your legs over the side of the bed when getting up from a lying down position. If you are taking medication to lower your blood pressure, you should have your blood pressure checked regularly.

Drowsiness/reduced alertness: Chlorpromazine may cause dizziness or drowsiness. Do not operate machinery or drive a car if the medication affects you in this way.

Glaucoma: If you have glaucoma, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Heart conditions: If you have heart disease or abnormal heart rhythms should discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Lab tests: While taking chlorpromazine, you will need to have your blood counts checked regularly by your doctor.

Liver disease: If you have impaired liver function or alcoholic liver disease, you should be closely monitored by your doctor while you are on this medication.

Lung disease or breathing problems: If you have lung disease or breathing problems, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Movement disorders: This medication is associated with a risk of developing tardive dyskinesia (TD), a condition involving repetitive, uncontrollable, and purposeless movements (such as grimacing; tongue protrusion; lip smacking; puckering; rapid eye blinking; rapid movements of the arms, legs, and body trunk). If you experience any of these symptoms, contact your doctor immediately.

Neuroleptic malignant syndrome (NMS): A risk of developing this condition has been associated with antipsychotic medication. If you experience increased sweating and sensations of warmth, muscle stiffness, emotional and behavioural changes, or irregular heartbeat, contact your doctor immediately. If you are taking this medication, you should take care to avoid becoming overheated or dehydrated.

Seizures: If you have a history of seizures, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Stopping the medication: Chlorpromazine is not addictive, but side effects may occur if stopped suddenly after taking high doses. Do not stop the medication without checking with your doctor first.

Sunlight: Chlorpromazine may make you more sensitive to sunlight. Protect your skin with clothing and a sunscreen with a sun protection factor (SPF) of at least 30 before going out into the sun.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately. Babies born to mothers that take this medication in the last 3 months of pregnancy may experience withdrawal symptoms after they are born, including breathing problems, difficulty feeding, or irritability. If you have been taking this medication during pregnancy, make sure that everyone involved in caring for you and your baby are aware.

Breast-feeding: This medication passes into breast milk. If you are breast-feeding and are taking chlorpromazine, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children under 18 years of age.

Seniors:  Seniors with dementia who take chlorpromazine or other similar medications are at an increased risk of dying. There may be a higher risk of liver, kidney, and heart problems, and a higher risk of drug interactions for seniors. Talk to your doctor about the risks and benefits of using this medication.

What other drugs could interact with this medication?

There may be an interaction between chlorpromazine and any of the following:

  • acetylcholinesterase inhibitors (e.g., donepezil, galantamine. rivastigmine)
  • aclidinium
  • alcohol
  • aldesleukin
  • alpha-agonists (e.g., clonidine, methyldopa)
  • alpha-blockers (e.g., alfuzosin, doxazosin, tamsulosin)
  • alfuzosin
  • amphetamines (e.g., dextroamphetamine, lisdexamfetamine)
  • angiotensin-converting enzyme inhibitors (ACEIs; captopril, enalapril, ramipril)
  • angiotensin receptor blockers (ARBs; e.g., candesartan, irbesartan, losartan)
  • antacids (e.g., aluminum hydroxide, calcium carbonate, magnesium hydroxide)
  • antiarrhythmics (e.g., amiodarone, dronedarone, flecainide, propafenone, quinidine)
  • antihistamines (e.g., bilastine, cetirizine, doxylamine, diphenhydramine, hydroxyzine, loratadine)
  • antimalarial medications (e.g. chloroquine, mefloquine, primaquine, proguanil)
  • anti-Parkinsons medications (e.g., amantadine, apomorphine, bromocriptine, levodopa, pramipexole, ropinirole)
  • antipsychotics (e.g., clozapine, lurasidone, olanzapine, quetiapine)
  • azelastine
  • "azole" antifungals (e.g., ketoconazole, fluconazole, itraconazole)
  • benzodiazepines (e.g., alprazolam, diazepam, lorazepam, midazolam)
  • beta-adrenergic blockers (e.g., atenolol, propranolol, sotalol)
  • beta-2 agonists (e.g. olodaterol, salbutamol, salmeterol, vilanterol)
  • botulinum toxin
  • brimonidine
  • bupropion
  • calcium channel blockers (e.g., amlodipine, diltiazem, verapamil)
  • cannabis
  • chloral hydrate
  • clonidine
  • conivaptan
  • diabetes medications (e.g., acarbose, canagliflozin, glyburide, insulin, linagliptin, lixisenatide, metformin, rosiglitazone)
  • diuretics (e.g., furosemide, hydrochlorothiazide)
  • domperidone
  • doxepin
  • efavirenz
  • eliglustat
  • eluxadoline
  • esketamine
  • eszopiclone
  • flibanserin
  • fingolimod
  • formoterol
  • glycopyrrolate
  • glycopyrronium
  • granisetron
  • guanfacine
  • HIV protease inhibitors (e.g., atazanavir, indinavir, lopinavir, nelfinavir, ritonavir)
  • ipratropium
  • lemborexant
  • linezolid
  • lithium
  • loperamide
  • macrolide antibiotics (e.g., clarithromycin, erythromycin)
  • methadone
  • methylene blue
  • metoclopramide
  • mifepristone
  • mirabegron
  • mirtazapine
  • monoamine oxidase inhibitors (MAOIs; e.g., moclobemide, phenelzine, rasagiline, selegiline, tranylcypromine)
  • muscle relaxants (e.g., baclofen, cyclobenzaprine, methocarbamol, orphenadrine)
  • nabilone
  • narcotic pain relievers (e.g., codeine, fentanyl, morphine, oxycodone, tramadol)
  • nitrates (e.g., nitroglycerin, isosorbide dinitrate, isosorbide mononitrate)
  • obinutuzumab
  • pentoxifylline
  • quinine
  • quinolone antibiotics (e.g., ciprofloxacin, moxifloxacin)
  • ondansetron
  • ozanimod
  • pasireotide
  • phosphodiesterase-5 inhibitors (e.g., sildenafil, tadalafil, vardenafil)
  • potassium chloride
  • protein kinase inhibitors (e.g., dasatinib, nilotinib, ribociclib, vandetanib)
  • riociguat
  • romidepsin
  • sacubitril
  • seizure medications (e.g., carbamazepine, gabapentin, levetiracetam, phenobarbital, phenytoin, topiramate, valproic acid)
  • selective serotonin reuptake inhibitors (SSRIs; e.g., citalopram, fluoxetine, paroxetine, sertraline)
  • serotonin-norepinephrine reuptake inhibitors (SNRIs; e.g., desvenlafaxine, duloxetine, venlafaxine)
  • siponimod
  • solifenacin
  • tacrolimus
  • tamoxifen
  • tamsulosin
  • tetrabenazine
  • tiotropium
  • trazodone
  • tricyclic antidepressants (e.g., amitriptyline, clomipramine, desipramine, trimipramine)
  • umeclidinium
  • valerian
  • zolpidem
  • zopiclone

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

  • stop taking one of the medications,
  • change one of the medications to another,
  • change how you are taking one or both of the medications, or
  • leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.

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