Methotrimeprazine (Nozinan)

Jill Sensenig
Author: Jill Sensenig Medical Reviewer: Amy Shelby Last updated:

Methotrimeprazine, also known as Levomepromazine, is an antipsychotic medication that is part of the phenothiazine drug class and is primarily used in the treatment of schizophrenia and manic phases of bipolar disorder. [12] Levomepromazine can increase the risk of severe adverse effects, including heart failure, a fast or irregular pulse, and pneumonia, which can be fatal in older adults with dementia. [9]

Methotrimeprazine brand names

Some brand names for methotrimeprazine include Nozinan®, Nosinan®, Levoprome® [8], and Neurocil®. [12] Two common generic names are Levomepromazine hydrochloride and Levomepromazine HCI. [12]

What is methotrimeprazine prescribed for?

Methotrimeprazine is primarily used to treat severe mental disorders such as psychosis and schizophrenia and the manic phases of bipolar disorder. It is also commonly used to treat pain, nausea, and vomiting and to ease other symptoms of end-of-life care, like delirium (confused thinking, being unaware of one’s surroundings) and agitation. [6]

Methotrimeprazine may be used to treat other mental and emotional health disorders, such as:

  • Personality Disorders [12]
  • Post-Traumatic Stress Disorder (PTSD)-associated sleep problems [2]
  • Depressive Disorder  [12}
  • Hallucinations (seeing or hearing something that doesnot exist) [12}
  • Agitation associated with acquired brain injury (ABI)[10]

Methotrimeprazine may be used to treat physical conditions, such as: 

  • Drug-induced Dyskinesia (involuntary, uncontrollable movements) [12]
  • Sciatica and back pain (therapeutic) [12]
  • Medicationu2010overuse headache as supportive treatment during detoxification [4]
  • Pre-operative sedative (sedatives help calm) [3]
  • Post-operative pain control [3]
  • Alleviating bronchoconstriction [3]

How does methotrimeprazine work?

Phenothiazine medications, like Levomepromazine, decrease the transmission of dopamine in the brain, which provides a quieting effect [5][12] and helps calm brain activity, reducing pain, nausea, and vomiting. Patients experience a detachment from their symptoms, and they are said to be less bothered by them. [11]

How is methotrimeprazine usually taken?

Methotrimeprazine is typically taken orally in tablet or liquid form. It is available as an intramuscular or intravenous injection (normally used in end-of-life care). 

It is always important to follow your doctor’s directions. Methotrimeprazine should not be crushed or chewed, only swallowed with a glass of water. [9] You may take it with food, but it is not required. 

Your doctor will determine the dosage and form of medication based on age, symptoms, and pre-existing medical conditions. Tablet form doses range from 2 mg to 50 mg. Oral solutions are available in 5 mg/mL, and intramuscular and intravenous solutions are available in 25 mg/mL strength.

Adults with schizophrenia typically start on 1-3 pills per day, divided into three doses. Individuals confined to bed may receive 4-8 tablets daily, divided into three doses. To determine the best dose for you, your doctor may change these doses. In general, children should not take more than 1-½ pills daily. [9]

Adults and the elderly typically receive ½ to 2 tablets every 4-8 hours for pain, but your doctor may change the dosage to achieve the desired results. Methotrimeprazine is not used to treat pain in children. [9]

If you miss a dose, take your tablets as soon as you remember. Do not take two doses to make up for a missed dose. If you are unsure, contact your doctor or pharmacist.

How long does methotrimeprazine stay in your system?

Methotrimeprazine remains in the body for 3-5 days on average [12] and about eight days in the brain. [7] Most drugs can be detected in urine from 1-3 days after last use [14] and in blood for about four days. [13] Most medications can remain in hair cells for around 90 days. [1]

Methotrimeprazine side effects

Medications can provide many benefits to improve symptoms and conditions, but side effects are possible. Drugs can have varying effects on different people, but the advantages often outweigh the risks, so it’s important to talk to your health provider about what options might work best for you. 

Methotrimeprazine can cause a variety of mild to severe physical and mental side effects.

Common side effects may include: [9]

  • Sleepiness
  • Dry mouth
  • Low blood pressure, especially in elderly patients or when quickly moving from lying down or sitting to standing
  • Heat stroke
  • Weakness 

Other side effects that are less common may include: [9] 

  • Musclestiffness or rigidity 
  • Constipation
  • Dizziness
  • Sensitivity, skin irritation, or burning due to sunlight
  • Priapism (unwanted erection lasting a long time)
  • Weight gain
  • Increase in the size or growth of breasts in men
  • Impotence (inability to achieve an erection or orgasm)
  • Lack of periods in women 

You may experience one or more of these common symptoms shortly after starting Methothrimeprazine. With time, your body will likely adjust, and the side effects may disappear. If symptoms worsen or continue, talk to your doctor.

Severe side effects are less likely, but may still happen. If you show any signs of allergic reaction such as severe skin itching, red rash or hives (red bumps), swelling of face, lips, tongue, or throat, or you have difficulty breathing, seek emergency help immediately.

A syndrome of inappropriate antidiuretic secretion (SIADH) can occur. You should call your doctor immediately if you or someone taking Methothrimeprazine has the following symptoms: [9]

  • Feeling unwell
  • Is confused or weak
  • Fatigue
  • Nausea
  • Loss of appetite
  • Feeling irritable 

You should call your medical provider if you experience severe side effects [9] such as:

  • Irregular heartbeat, heart palpitations, fast heartbeat, or chest pain
  • Jaundice (yellow skin or eyes)
  • Seizures
  • Swelling, pain, or redness in legs
  • Difficulty breathing or rapid breathing
  • Looking unusually pale
  • Fever or sweating
  • Difficulty passing urine, dark urine, or bloody stool
  • Confusion or anxiety
  • Trouble walking or unbalanced walking
  • Extreme weakness or sleepiness
  • Involuntary shaking or muscle movements
  • Rolling of the eyes
  • Abdominal pain
  • High blood sugar (hyperglycemia)
  • Vision problems or changes, such as problems with seeing close up or far away, or if you notice brown-like deposits in your eye[9]

Methotrimeprazine precautions

Don’t take Methotrimeprazine if you are allergic to it or its ingredients, [9] if you have a history of constipation, stomach bloating, or pain or if you have had a blocked intestine (paralytic ileus). [9] 

Talking to your doctor about all your medications and health conditions is important. You should speak with your doctor before taking Methotrimeprazine if you have any of the following health conditions: [9]

  • Liver or kidney problems
  • You are elderly with dementia or heart disease or have problems with dizziness or feeling faint when you move from lying or sitting to standing due to low blood pressure. Methotrimeprazine can make you feel faint or lightheaded. If prescribed a large starting dose, you will need to stay in bed and should not attempt to get up quickly without assistance.
  • A history of slow or irregular heartbeats, palpitations (torsades de pointes), heart issues, or blood clots
  • High blood pressure, high blood sugar, or high cholesterol. Methotrimeprazine can cause strokes or increase the risk of strokes, especially if you have one of these conditions.
  • Diabetes or you are at high risk for developing diabetes. Your doctor will need to monitor your blood sugar levels carefully.
  • Hypokalemia or Hypocalcemia (low levels of potassium or calcium in the blood)
  • Magnesium deficiency (low levels of magnesium in your blood)
  • Constipation or difficulty eating
  • If you have problems with alcohol or you are an alcoholic
  • Epilepsy or have experienced convulsions
  • Enlarged prostate or an adrenal gland tumor
  • Hypothyroidism (your body doesn’t produce enough thyroid hormone)
  • Eyelid drooping, double vision, difficulty speaking or swallowing, or muscle weakness in your arms or legs (myasthenia gravis)[9] 

Your health provider will order tests before prescribing Nozinan while on it or if you are taking other drugs for your heart, anti-depressants, or other mental health conditions. [9] These tests include: [9] 

  • Blood tests to check your liver function white blood cell, counts
  • Electrocardiogram (ECG) to check to ensure you don’t have any problems with your heart and its functioning

You should tell your doctor if you need to go to the dentist. [9] Talk to your doctor before starting methotrimeprazine if you could become pregnant and are not using effective birth control, if you are pregnant, or plan to become pregnant. Methotrimeprazine taken during pregnancy can harm the baby and impact fertility. Don’t breastfeed while on Methotrimeprazine. [9]

Methotrimeprazine can make you sleepy, confused, disoriented, lightheaded, and dizzy, so avoid operating machinery or a vehicle while taking it. [9] 

It is important to keep scheduled appointments with your healthcare provider and take your medication as prescribed. Do not stop Methotrimeprazine or start a new medication without talking to your healthcare provider.

Methotrimeprazine interactions

Do not take Methotrimeprazine tablets, and tell your health provider or pharmacist if you are taking any of the following medications: [9]

Keep a list that includes all prescription, non-prescription, supplement, and herbal products, and share it with your doctor.

Before you start taking Methotrimeprazine, tell your health provider or pharmacist if you are taking any of the following: [9]

  • Parkinson’s medications
  • Cabergoline or quinagolide
  • Medications that contain alcohol
  • Desferrioxamine
  • Epinephrine
  • Heart medications
  • Anti-depressantor antipsychotic drugs
  • Anxiety medications or other sedatives
  • Anti-parasitics(used to treat diseases caused by parasites)
  • Antibiotics
  • Mizolastine
  • Cancer medications
  • Dolasetron
  • Vincamine
  • Diphemanil
  • Prucalopride
  • Mequitazine
  • Methadone

Do not drink alcohol while you are taking Methotrimeprazine. Avoid drinking black tea or coffee since they reduce Methotrimeprazine absorption. [8][9]

Methotrimeprazine storage

Methotrimeprazine should be stored in its original container, in a cool dark place, and away from high humidity. It should be stored at temperatures under 25º C (77º F) and away from light. [9]

Keep Methotrimeprazine out of reach of children and in a secure location. Do not share or give prescription medication to anyone else. It is illegal to share or sell prescription drugs with others. Failing to keep medications away from children or others can cause severe medical problems and may be fatal.

Do not flush unused medication or throw it away in the trash. Check with your local pharmacy or health provider’s office about methods to safely dispose of unused prescriptions or for information on drug-takeback programs.

What to do if you overdose on methotrimeprazine

A deliberate or accidental overdose of Methotrimeprazine is dangerous and can be fatal. If you or a child accidentally swallow too many tablets, call your doctor or the nearest hospital emergency department immediately.

It is important to seek medical attention immediately if someone shows any signs of overdose [9], such as: 

  • Drowsiness
  • Convulsions
  • Low blood pressure
  • Irregular heartbeat
  • Hypothermia (low body temperature)
  • Involuntary movements [9]

You should immediately contact your healthcare provider or the poison control center for additional treatment information if a drug overdose is suspected. The number for the poison control center is 1-800-222-1222. 

If someone has collapsed, is unconscious, has a seizure, or has problems breathing, immediately call 911 for emergency services. Delaying treatment of severe symptoms can cause long-term damage or even death.

  1. Arnold, A. (2018). How long do drugs stay in your hair? US Drug Test Centers. Retrieved from
  2. Aukst-Margetić, B., Margetić, B., Tosić, G., & Bilić-Prcić, A. (2004). Levomepromazine helps to reduce sleep problems in patients with PTSD. European Psychiatry: The Journal of the Association of European Psychiatrists, 19(4), 235–236.
  3. Green, B., Pettit, T., Faith, L., & Seaton, K. (2004). Focus on levomepromazine. Current Medical Research and Opinion, 20(12), 1877–1881.
  4. Højlund, M., Pottegård, A., Johnsen, E., Kroken, R. A., Reutfors, J., Munk-Jørgensen, P., & Correll, C. U. (2019). Trends in utilization and dosing of antipsychotic drugs in Scandinavia: Comparison of 2006 and 2016. British Journal of Clinical Pharmacology, 85(7), 1598–1606.
  5. Kapur S, Agid O, Mizrahi R, Li M. How antipsychotics work-from receptors to reality. NeuroRx. 2006 Jan;3(1):10-21. doi: 10.1016/j.nurx.2005.12.003. PMID: 16490410; PMCID: PMC3593357.
  6. Kidron A, Nguyen H. Phenothiazine. [Updated 2022 May 29]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan. Available from:
  7. Kornhuber, J., Wiltfang, J., Riederer, P., & Bleich, S. (2006). Neuroleptic drugs in the human brain: Clinical impact of persistence and region-specific distribution. European Archives of Psychiatry and Clinical Neuroscience, 256(5), 274–280.
  8. (n.d.). Levomepromazine. Retrieved from
  9. Manufacturer’s PIL, Nozinan® 25 mg tablets; Sanofi, The Electronic Medicines Compendium. Retrieved from
  10. Maryniak, O., Manchanda, R., & Velani, A. (2001). Methotrimeprazine in the treatment of agitation in acquired brain injury patients. Brain Injury, 15(2), 167–174.
  11. Mizrahi, R., Bagby, R. M., Zipursky, R. B., & Kapur, S. (2005). How antipsychotics work: The patients’ perspective. Progress in Neuro-Psychopharmacology & Biological Psychiatry, 29(5), 859–864.
  12. National Center for Biotechnology Information (2022). PubChem Compound Summary for CID 72287, Levomepromazine. Retrieved November 1, 2022, from
  13. Schoretsanitis, G., Kane, J. M., Correll, C. U., et al. American Society of Clinical Psychopharmacology, & Pharmakopsychiatrie, T. (2020). Blood levels to optimize antipsychotic treatment in clinical practice: A joint consensus statement of the American Society of Clinical Psychopharmacology and the Therapeutic Drug Monitoring Task Force of the Arbeitsgemeinschaft für Neuropsychopharmakologie und Pharmakopsychiatrie. The Journal of Clinical Psychiatry, 81(3), 19cs13169.
  14. Wilkening, G. L., Hale, G. M., & Ross, C. (2016). Urine drug screens: Considerations for the psychiatric pharmacist. The Mental Health Clinician, 6(1), 42–47.
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Jill Sensenig
Author Jill Sensenig Writer

Jill Sensenig is a medical writer with 16+ years experience in the healthcare industry as a writer, editor, and author.

Published: Nov 22nd 2022, Last edited: Feb 21st 2024

Amy Shelby
Medical Reviewer Amy Shelby M.S. Counseling Psychology

Amy Shelby is a medical reviewer with a B.A. in Psychology from Northwestern and an M.S. in Psychology from Chatham University.

Content reviewed by a medical professional. Last reviewed: Nov 23rd 2022