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Brand Name: Apo-Methoprazine
Common Name: methotrimeprazine

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

Methotrimeprazine belongs to the class of medications called phenothiazines. It is used to treat mental and emotional disorders, including schizophrenia and other psychotic disorders. It can also be used in conditions associated with anxiety and tension, as a pain reliever (for certain types of pain), as a sedative, and for nausea and vomiting caused by certain conditions.

Your doctor may have suggested this medication for conditions other than the ones listed in these drug information articles. As well, some forms of this medication may not be used for all of the conditions discussed here. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking 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 take this medication if their doctor has not prescribed it.

How should I use this medication?

The dose of this medication varies widely depending on the condition being treated and the circumstances and age of the person being treated.

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 taking the medication without consulting your doctor.

It is important to take this medication exactly as prescribed by your doctor. If you miss a dose, contact your doctor or pharmacist for advice. Do not take a double dose to make up for a missed one.

Store this medication at room temperature, protect it from light and moisture, 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.

What form(s) does this medication come in?

This medication is available as 2 mg, 5 mg, 25 mg, and 50 mg tablets.

Who should NOT take this medication?

Do not take methotrimeprazine if you:

  • are allergic to methotrimeprazine, other phenothiazines (e.g., chlorpromazine)s, or any ingredient of this medication
  • are excessively sedated by alcohol, sleeping pills, tranquilizers, pain relievers, or narcotics
  • have a blood disorder
  • have liver problems

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.

  • Drowsiness may appear early in treatment but will gradually disappear during the first weeks or with an adjustment in the dosage.
  • Dryness of the mouth and, in older patients, occasional urinary retention, constipation, and fast heart rate may occur.

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

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

  • high blood sugar (symptoms include increased thirst, decreased appetite, nausea and vomiting)
  • low blood pressure (symptoms include dizziness, especially when moving to a standing position)

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

  • allergic reactions, such as skin rash, redness, or itching
  • fast or irregular heartbeat, high or low blood pressure
  • increased sweating, confusion, or reduced consciousness
  • muscle twitching or uncontrolled movements of the mouth, tongue, face, or jaw
  • pain, swelling , redness, or warmth in arms or legs, chest pain, anxiety, or coughing up blood
  • painful erection lasting more than 4 hours
  • respiratory infection, fever, flu-like symptoms, coughing, difficult or fast breathing
  • shaking, muscle stiffness, body spasm, impairment of voluntary movement, upward eye rolling, exaggeration of reflexes or drooling
  • sore mouth, gums, or throat; abdominal pain; or jaundice (yellow eyes or skin)

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.


June 15, 2011

Health Canada has issued information concerning the use of methotrimeprazine. To read the full Health Canada Advisory, visit Health Canada's web site at

Diabetes: If you have diabetes, your doctor should closely monitor your condition while you are taking methotrimeprazine, as it may affect blood sugar control.

Dizziness/lightheadedness: In high doses, dizziness or lightheadedness when getting up from a sitting or lying position may be experienced at the start of treatment.

Drowsiness/reduced alertness: Methotrimeprazine can cause drowsiness and reduce alertness, especially during the first few days of treatment. Do not drive or participate in activities requiring mental alertness if the medication affects you in this way.

Medical conditions: If you have arteriosclerosis, heart problems, glaucoma, or prostate 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.

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.

Breast-feeding: It is not known if methotrimeprazine passes into breast milk. If you are a breast-feeding mother and are taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

What other drugs could interact with this medication?

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

  • antihistamines (e.g., diphenhydramine)
  • barbiturates (e.g., phenobarbital)
  • dronedarone
  • metoclopramide
  • narcotics (e.g., codeine, morphine)
  • nilotinib
  • other phenothiazines (e.g., chlorpromazine)
  • pimozide
  • quinine
  • tamoxifen
  • tetrabenazine
  • ziprasidone

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.

All material copyright MediResource Inc. Terms and conditions of use. The contents herein are for informational purposes only. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.

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