How levomepromazine works
Levomepromazine has a calming, sedative, pain-relieving, sleep-promoting and mildly antipsychotic effect. The active ingredient also helps against nausea and vomiting (antiemetic effect).
Levomepromazine develops these effects by inhibiting various docking sites (receptors) of the body’s own nerve messengers (neurotransmitters) serotonin, histamine, acetylcholine and dopamine. They transmit signals between the nerve cells.
In states of restlessness and agitation, the amount of dopamine in parts of the brain is often increased. Levomepromazine binds primarily to the dopamine receptors in the mesolimbic system in the brain. As a result, dopamine can no longer bind to it and exert its effect. This dampens the heightened perception of stimuli and impressions from the environment (for example in the form of hallucinations) that often occurs in mental illnesses. In this way, levomepromazine has an antipsychotic effect.
Levomepromazine is a low-potency antipsychotic. This means that the active ingredient binds less strongly to the dopamine receptors than more potent antipsychotics. It therefore only has a stronger antipsychotic effect at higher doses.
There are also histamine receptors in the brain through which the neurotransmitter histamine triggers wakefulness. By occupying these receptors, levomepromazine makes it easier to fall asleep and wake up less frequently.
Levomepromazine also blocks other binding sites of nerve messengers in the body, which primarily triggers the side effects of the active ingredient. These include
- Muscarinic receptors (binding sites of acetylcholine): By blocking these, levomepromazine inhibits the effect of acetylcholine. This results in anticholinergic effects (= effects directed against the action of acetylcholine) such as constipation.
- Alpha-1-adrenoceptors (binding sites of adrenaline and noradrenaline): their inhibition dilates the blood vessels and thus causes lowered blood pressure or dizziness.
You can read more about this in the side effects section below!
Levomepromazine: onset of action
The antiemetic, sleep-inducing, sedative-dampening and pain-relieving effects of levomepromazine usually set in within 30 minutes to a few hours. The antipsychotic effect develops a few days to weeks later.
How levomepromazine is used
Pay particular attention to the exact dosage when using levomepromazine drops. You will find instructions for correct use in the package leaflet for your levomepromazine medication. If you have any questions, ask your doctor or pharmacist.
Levomepromazine for anxiety and agitation
Depending on the country, preparations containing levomepromazine are commercially available in different dosages. As a rule, doctors initially prescribe a low dose to their patients. They then slowly increase this dose until the patient’s symptoms improve sufficiently.
In general, the exact dosage of levomepromazine in individual cases depends on several factors. For example, the patient’s illness and how they react to the active substance play a role.
Doctors also take age and any concomitant illnesses into account. For example, older patients and patients with impaired liver or kidney function often develop more side effects. The doctor may therefore reduce the dose of levomepromazine.
Levomepromazine for severe or chronic pain
Levomepromazine in palliative care
Doctors sometimes use levomepromazine off-label to treat nausea in palliative care. It is administered as a tablet or injection, for example. The exact dosage and number of doses per day is determined by the treating doctor in each individual case.
What side effects does levomepromazine have?
Patients’ blood pressure often drops when they get up quickly from a sitting or lying position, especially at the beginning of levomepromazine treatment. As a result, those affected feel dizzy or “black in the eyes”. Doctors refer to this as orthostatic dysregulation.
These symptoms are triggered by the inhibitory effect of levomepromazine on alpha-1 receptors, among other things. The feeling of a blocked nose that many patients develop is also caused in this way. These symptoms usually improve on their own after a while.
The active ingredient often increases the appetite. This is why patients often gain weight during treatment with levomepromazine.
The sedative and sleep-inducing effect of levomepromazine is responsible for other common side effects. Many patients are tired or sleepy, especially at the beginning of treatment.
By blocking the dopamine receptors, levomepromazine triggers symptoms of dopamine deficiency: Movement disorders occur, especially at high doses, which experts refer to as extrapyramidal motor disorders (EPMS). The symptoms are similar to those of Parkinson’s disease, which is also characterized by a dopamine deficiency.
The movement disorders often occur early during treatment (early dyskinesia). For example, those affected develop eye or tongue spasms (jerky sticking out of the tongue) or the back muscles stiffen. Such early dyskinesias are usually easy to treat and generally disappear.
This is not the case with movement disorders that only develop after long-term use of levomepromazine (or after its discontinuation). These so-called tardive dyskinesias mainly occur in the mouth area and are sometimes permanent. Women and older people are particularly susceptible.
If you notice symptoms that may indicate a malignant neuroleptic syndrome, you should not take another dose of levomepromazine and instead call a doctor immediately.
By blocking the muscarinic receptors, levomepromazine triggers anticholinergic side effects (i.e. effects directed against the action of acetylcholine): Patients often have increased intraocular pressure, dry mouth or suffer from constipation because the bowels work more slowly.
In rare cases, levomepromazine disrupts conduction in the heart muscle (prolongation of the QT time – a time interval in the ECG). As a result, the active substance occasionally triggers torsade de pointes tachycardia. This is a specific form of cardiac arrhythmia. Those affected often experience an irregular heartbeat or feel dizzy and nauseous.
Contact a doctor immediately if you suspect cardiac arrhythmia while taking levomepromazine.
The active substance may make the patient’s skin more sensitive to light. While using levomepromazine, patients should therefore ensure that they use adequate sun protection, avoid direct sunlight as far as possible and refrain from going to the solarium.
Additional information on possible undesirable side effects can be found in the package leaflet of your levomepromazine medication. Contact your doctor or pharmacist if you notice or suspect any other side effects.
When do doctors use levomepromazine?
In Germany, Austria and Switzerland, doctors sometimes use levomepromazine for various conditions in adult patients.
Use in Germany
The areas of application in Germany include
- severe restlessness and agitation in patients with mental illnesses
- manic phases in the context of bipolar disorders
- in combination with painkillers for the treatment of severe or chronic pain
In palliative care, doctors use levomepromazine to treat nausea when other medications are not effective enough. If patients are particularly restless or confused in the last days of their lives, they are also given levomepromazine to calm them down. The active ingredient is not approved for use in palliative care, so doctors use it in off-label use, i.e. outside of the approval.
Use in Austria
In Austria, doctors prescribe levomepromazine for:
- schizophrenic disorders
- short-term mental disorders, usually caused by traumatizing experiences, accompanied by anxiety and restlessness
Use in Switzerland
In Switzerland, patients receive levomepromazine for:
- psychomotor agitation: Disorders of movement, facial expressions or speech that are often associated with mental illness
- schizophrenic illnesses
- mental illnesses with hallucinations
- manic phases in the context of bipolar disorders
- Aggressiveness with mental disabilities
These interactions can occur with levomepromazine
If patients are taking anticholinergic agents at the same time, anticholinergic side effects may occur more frequently. Possible consequences include an attack of glaucoma (acute glaucoma), urinary retention or intestinal paralysis (paralytic ileus). One example of an anticholinergic agent is biperiden (a drug used to treat Parkinson’s disease).
If patients are taking centrally depressant drugs at the same time, the effects may be mutually reinforcing. These include, for example:
- Tranquilizers (sedatives)
- Painkillers from the opioid group
- Medication for the treatment of depression (antidepressants)
- Medication for the treatment of epilepsy (antiepileptic drugs)
- Antihistamines (medication against allergies) such as cetirizine
Alcohol also has a central depressant effect. Therefore, patients should not drink alcohol during levomepromazine therapy.
The simultaneous use of phenytoin (for epilepsy) or lithium (for mental illnesses) may cause severe side effects.
Levomepromazine inhibits a certain enzyme system in the liver (CYP-2D6 system). This may increase the amount of active substances in the blood that are broken down via this system. Stronger effects and side effects are then possible. Examples of these active substances are haloperidol (for psychoses) and codeine (for dry coughs).
Simultaneous intake with medicines or foods containing magnesium, aluminum and calcium (such as milk) impairs the absorption and thus the effect of levomepromazine. Patients should therefore ideally take levomepromazine at least two hours later.
When should levomepromazine not be used?
The contraindications for the use of levomepromazine vary depending on the preparation. Often mentioned are, for example
- Hypersensitivity to the active ingredient, related substances (phenothiazines or thioxanthenes) or other components of the medication
- Acute poisoning with alcohol, sleeping pills or painkillers or other drugs for the treatment of mental illnesses (antipsychotics, tranquilizers, antidepressants)
- coma
- Circulatory shock
- Agranulocytosis (severe deficiency or absence of granulocytes – a subgroup of white blood cells)
- Porphyria (group of metabolic diseases with impaired formation of the red blood pigment)
- Simultaneous use of so-called monoamine oxidase inhibitors (MAO inhibitors), for example tranylcypromine (active ingredient for the treatment of depression)
- concomitant use of so-called dopamine agonists such as amantadine (for the treatment of Parkinson’s disease, among other things), unless you suffer from Parkinson’s disease
- multiple sclerosis
For some pre-existing conditions, the doctor will decide on a case-by-case basis whether levomepromazine can be used. These include, among others
- Liver and kidney dysfunction
- Cardiovascular diseases such as congenital long QT syndrome
- Severe fluctuations in blood pressure
- damage to the brain or a history of seizures
- constricted or blocked sections of the intestine or urinary tract
- glaucoma
- concomitant use of medication that prolongs the QT interval, such as the antibiotics moxifloxacin or erythromycin
- Enlargement of the prostate
- Pheochromocytoma (tumor of the adrenal medulla)
Levomepromazine in children: What should be considered?
There is no experience with the use of levomepromazine in children and adolescents under the age of 16 or 18 (depending on the preparation). The active substance should therefore not be used in this age group.
In Austria, doctors use levomepromazine in exceptional cases in children if no other treatment options are available. The dosage is determined by doctors on a case-by-case basis.
In Germany, doctors occasionally use levomepromazine in children suffering from severe states of confusion (delirium). The active ingredient is also used to calm children in intensive care medicine. The exact dose is determined individually for each patient by the treating physicians.
Levomepromazine during pregnancy and breastfeeding
Doctors therefore mainly use better-studied active substances during pregnancy, such as promethazine or quetiapine. If levomepromazine is taken in the first trimester of pregnancy, doctors may recommend additional ultrasound examinations to ensure the correct development of the unborn child.
There is hardly any data available on the use of levomepromazine during breastfeeding. If a mother only takes the drug once, she does not have to stop breastfeeding. Breastfeeding is also possible while taking low doses of the active ingredient. Careful attention should be paid to possible side effects in the child. After a few weeks, the amount of active substance in the child’s blood can also be determined to rule out the possibility of excessive amounts of levomepromazine accumulating.
If you are using levomepromazine and are planning a pregnancy or become pregnant, you should contact your doctor immediately. He or she will discuss the next steps with you.
How to obtain medication containing levomepromazine
Medication containing levomepromazine is only available on prescription in Germany, Austria and Switzerland. Patients can therefore only obtain them from a pharmacy with a prescription.
Further important information on levomepromazine
Some patients use levomepromazine as a sleeping pill to help them fall asleep and stay asleep. Misuse by healthy patients can cause severe drowsiness and dizziness as well as serious side effects such as cardiac arrhythmia or breathing problems. Levomepromazine is therefore rarely used as a drug or to induce intoxication.
If the dose of levomepromazine is too high, those affected become confused, suffer from cardiac arrhythmia and even circulatory failure and coma. Breathing also decreases significantly. The patient’s mucous membranes dry out, constipation and urinary retention occur. In some cases, eye and tongue spasms also develop in the event of an overdose of the active ingredient.
An overdose of levomepromazine is always a medical emergency. In severe cases, too high a dose can lead to coma or respiratory arrest, which can be fatal. If you notice symptoms of an overdose, do not take another dose and call an ambulance immediately.
