Avomine

Quick links to important sections

Medically reviewed

Marina Burgos

Last updated on 10/01/2026

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Avomine

Property Description
Active ingredient Promethazine Theoclate
Form Tablet
Pharmacological class First-generation H1 Antagonist, Anti-emetic agent
General purpose Motion sickness and balance disturbances
Origin Synthetic, Phenothiazine derivative

Avomine: Definition and Pharmacological Classification

Avomine is a synthetic medicinal preparation primarily containing the single active substance, Promethazine Theoclate, administered orally in a tablet dosage form. The compound is chemically categorized as a Phenothiazine derivative, which establishes its structural origin and synthetic nature.

The drug is universally classified as a First-generation H1 Receptor Antagonist and, critically, an Anti-emetic agent. This classification is clinically recognized for defining its ability to influence the central nervous system (CNS), which is essential for its primary function. The H1 receptor antagonism is a fundamental mechanism of action for this compound, helping to stabilize the body’s reaction to stimuli that cause motion sickness. Avomine is specifically known for its use as a preventive measure, such as before a long journey.

Composition, Form, and General Therapeutic Purpose

The preparation is a single-ingredient product where Promethazine Theoclate is combined with standard solid pharmaceutical excipients necessary for its compressed tablet form. This medication is fundamentally designed to provide relief from symptoms associated with motion sensitivity and balance disturbances.

Its general therapeutic purpose is directly linked to its dual pharmacological profile, as it acts on the receptors responsible for both allergic responses and the sensation of nausea. By targeting the brain centers controlling the emetic response, such as nausea and vomiting, and by modulating signals originating from the inner ear, Avomine helps stabilize the body's reaction to disruptive movements. The drug’s therapeutic focus is therefore to alleviate the acute discomfort and dizziness typically associated with motion sickness and related labyrinthine disorders.

Regulatory References

  1. Antihistamines - StatPearls
  2. Promethazine - StatPearls - NIH
  3. Promethazine: MedlinePlus Drug Information
  4. Promethazine: Uses & Side Effects - Cleveland Clinic
  5. Labyrinthitis and vestibular neuritis - NHS

What side effects are possible with Avomine?

Possible Side Effects and Safety Information

The official regulatory safety profile for Avomine (Promethazine Theoclate) is defined by a set of adverse reactions categorized by frequency and the body systems they affect.

Adverse Reaction Classification

Side effects are most frequently associated with effects on the Nervous System and secondary Anticholinergic properties. Drowsiness and sedation are generally classified as common or very common adverse reactions, often being most noticeable at the start of treatment. Less common effects include dry mouth, blurred vision, and constipation.

Officially documented reactions span several System-Organ Classes, including Gastrointestinal Disorders, Eye Disorders, and Vascular Disorders (e.g., hypotension). The drug is also associated with photosensitivity (increased skin sensitivity to sunlight).

Serious Adverse Reactions and Safety Constraints

The regulatory labels specify the potential for serious adverse reactions, although these are rare. Documented serious risks include certain Blood and Lymphatic System Disorders, such as agranulocytosis, and Neuroleptic Malignant Syndrome ( NMS).

Safety data notes specific considerations for certain patient populations. Older adults are considered to have an increased risk of confusion, sedation, and hypotension. Pediatric patients may exhibit paradoxical reactions, such as excitement or restlessness. The medication is officially contraindicated in individuals with severe central nervous system depression or a comatose state.

Overdose and Emergency Response

Overdose and When to Seek Help

The official regulatory documentation for Promethazine Theoclate describes specific manifestations of overdose, primarily affecting the Central Nervous System (CNS) and the cardiovascular system. CNS presentation can be biphasic, ranging from excitement, agitation, hallucinations, and seizures to severe drowsiness, respiratory depression, and coma. Documented anticholinergic effects include fever, blurred vision, urinary retention, and dilated pupils.

Overdose is associated with severe or life-threatening outcomes, including potentially fatal respiratory depression and serious cardiac conduction abnormalities (dysrhythmias) and hypotension. Regulatory guidance explicitly notes the risk of sudden death in pediatric patients with excessive dosages and the possibility of developing Neuroleptic Malignant Syndrome (NMS). The elderly are noted to be particularly susceptible to pronounced anticholinergic effects and confusion.

Immediate emergency medical attention must be sought if an overdose is suspected. Urgent services must be contacted if the individual has collapsed, is seizing, has trouble breathing, or is unable to be awakened. Management is defined as symptomatic and supportive, requiring measures such as airway support and cardiac monitoring. The official labeling strictly mandates that epinephrine must not be used to treat associated low blood pressure.

Therapeutic Uses of Avomine

What Avomine Treats: Main Uses and Benefits

Avomine (promethazine teoclate) is a medication that is commonly used across conditions presenting with acute episodes where symptomatic relief is needed, primarily due to its anti-sickness and sedative properties. The core therapeutic domain of Avomine is in the prevention and management of motion sickness, which involves symptoms related to systemic imbalance such as nausea, vomiting, and dizziness.

The active ingredient is also applied across domains where additional symptomatic support is needed. These uses may include the management of nausea and vomiting from various causes, as well as providing short-term symptomatic assistance for certain allergies and for sedation. This supportive relief is applied in scenarios where additional management of discomfort is required. This action contributes to improved comfort during periods of heightened physiological activity and assists with maintaining functional stability when symptoms that interfere with daily functioning become more noticeable.

“This drug is considered relevant when supportive symptom management is appropriate and may help patients cope more steadily with symptom fluctuations.”

Quick Fact: Relief for Motion Sickness and Nausea

Regulatory References

  1. NIH MedlinePlus Drug Information on Promethazine

Eligibility and Restrictions for Use

Eligibility Map: Who Can and Cannot Use Avomine

Official regulatory documents strictly define the patient populations eligible for Avomine (Promethazine Theoclate) use. The criteria are categorized by absolute contraindications, age restrictions, and pre-existing medical conditions.

Absolute Contraindications

Avomine must not be used in the following populations:

  • Pediatric patients less than two (2) years of age due to the serious risk of fatal respiratory depression.
  • Patients in a comatose state or suffering from severe Central Nervous System (CNS) depression.
  • Individuals with known hypersensitivity to promethazine, other phenothiazines, or any excipients.
  • Patients being treated for Lower Respiratory Tract Symptoms (LRS), including asthma.
  • Patients who have used Monoamine Oxidase Inhibitors (MAOIs) within the previous 14 days.

Age-Related Eligibility and Restrictions

Age Group Regulatory Status
Infants/Toddlers (under 2 years) Contraindicated (absolute prohibition)
Children (2 to 5 years) Use with caution or not recommended (varies by region)
Adults Eligible under standard labeled conditions
Older Adults (Geriatric) Use with caution due to increased susceptibility to anticholinergic effects

Condition-Specific Restrictions

Use requires caution in patients with conditions such as seizure disorders, narrow-angle glaucoma, bladder-neck obstruction, pyloroduodenal obstruction, or hepatic (liver) impairment.

Pregnancy and Lactation

Use is not recommended in breastfeeding patients and should be avoided during the last two weeks of pregnancy.

What should I know about interactions with other medicines?

Interaction Map: Interactions with other medicines and products — official regulatory information for Avomine

Property Description (Strictly Regulatory Information)
Medicinal product categories with documented interactions CNS depressants, Anticholinergic agents, Monoamine Oxidase Inhibitors (MAOIs), QTc-prolonging agents, Ototoxic medications, and specific CYP2D6 inhibitors.
Mechanistic basis of interactions (only if stated in label) Pharmacodynamic potentiation (e.g., additive CNS depression); Pharmacokinetic inhibition (reduced clearance via inhibition of the hepatic enzyme CYP2D6).
Interaction-related restrictions Prohibited co-administration with alcohol and alcohol-containing medicines; Contraindicated with strong CYP2D6 inhibitors (e.g., Mavorixafor).

Interaction Classifications (High-Level)

Classification Description (Strictly Regulatory Information)
Interaction severity classification (as defined in official documents) Contraindicated (e.g., MAOIs, QTc-prolonging agents, large doses of CNS depressants). Clinically significant (e.g., Ototoxic medications).
Interaction-context constraints (as defined in official documents) Interference with immunologic urine pregnancy tests (false results) and inhibition of the histamine response during allergy skin tests.

Resulting Interaction Structure

Official Interaction Statements:

  • Co-administration with Monoamine Oxidase Inhibitors (MAOIs) is contraindicated due to increased risk of extrapyramidal effects and requires a 14-day washout period.
  • The use of Promethazine with QTc-prolonging agents (e.g., pimozide, sotalol) is officially prohibited.
  • Promethazine potentiates the sedative action of all co-administered CNS depressants (e.g., narcotics, barbiturates, tranquilizers).
  • The drug may mask the warning signs of ototoxicity caused by co-administered ototoxic agents.
  • Promethazine must be discontinued at least 72 hours prior to allergy skin testing to prevent diagnostic interference.

Connection to the overall interaction profile (2–4 sentences):

The regulatory documents specify that the product’s interaction structure is based on critical contraindications due to severe risk, such as with MAOIs and QTc-prolonging agents. The most common interaction pattern is the additive effect with other CNS depressants, alongside mandated timing requirements for diagnostic procedures to prevent false or misleading results.

Mechanism of Action

Avomine's action is defined by a multi-target receptor blockade within the central nervous system (CNS), which functionally dampens neural signaling pathways that process motion and equilibrium. This mechanism relies on high affinity for specific neural targets, resulting in modulation of system responsiveness.

Central Multi-Receptor Blockade

The active component, Promethazine, functions as an antagonist, binding primarily to the Histamine H1 receptors and muscarinic acetylcholine receptors ( M) in the brain. This multi-receptor blockade directly suppresses the binding and signaling of the body's natural transmitters (Histamine and Acetylcholine), which are key mediators of both central arousal and equilibrium signaling. This molecular step achieves broad dampening across sensitive CNS structures.

Suppression of Vestibular and Emetic Centers

The antagonistic effect occurs in two critical brainstem areas: the Vestibular Nuclei and the Chemoreceptor Trigger Zone (CTZ). By blocking H1 and M receptors in the Vestibular Nuclei, the drug reduces the excitability and transmission of neural signals originating from the labyrinthine apparatus (inner ear). Concurrently, antagonism in the CTZ (a key sensory area in the brainstem) increases the stimulus intensity required for activation of the involuntary emetic reflex.

Mechanistic Basis for Physiological Modulation

This multi-faceted mechanism results in two core physiological effects: the modulation of Vestibular Pathway responsiveness and a general depression of the CNS. The combined suppression of both the signal input and the central processing command center adjusts the physiological response to incoming vestibular signals, contributing to a modulated signal output from these pathways. The mechanism is dependent on reaching these targets before the relevant pathways become highly activated by the stimulus.

Dosage and Administration Information

Official Administration Guidelines for Avomine (Promethazine Theoclate)

Avomine tablets are intended for oral administration and should be used as directed for safety and efficacy. The tablet should be swallowed whole with water; it must not be crushed or chewed. It may be taken with or without food.

Dosage Timing for Motion Sickness

  • Prevention (Long Journeys): Take a single 25 mg tablet at bedtime the night before travel begins.
  • Prevention (Short Journeys): Take a single 25 mg tablet 1 to 2 hours before the journey commences.
  • Treatment: Take 25 mg as soon as symptoms start, repeating the same dose in the evening and once on the following evening if required. It is seldom necessary to repeat a dose in less than 8 hours, and the maximum dose is 100 mg (four tablets) in a 24-hour period.

Population-Specific Dosing

Age Group Recommended Dose
Adults and Children over 10 years 25 mg (one tablet).
Children 5 to 10 years Half the adult dose (half a tablet).
Children 2 to 5 years Tablets are generally not suitable; an oral liquid form is recommended.
Children under 2 years Do not use.

Administration Conditions

If the medicine is taken for a treatment course, it should generally not be used for longer than 7 days. The product must also be discontinued for a period of 72 hours before certain allergy skin testing to avoid interference with test results. If a dose for motion sickness is missed, take it as soon as it is remembered. Do not take a double dose to make up for a missed one.

Recent Clinical Evidence

Research Evidence: Overview of Studies for Avomine (Promethazine Theoclate)

The research record for Promethazine Theoclate is primarily built upon studies that examine its use in motion-related disturbances and outcomes related to acute nausea. The available evidence, largely from controlled laboratory settings and specific clinical trials, describes the type of research conducted and what outcomes researchers have monitored.

Evidence for Use in Motion Sickness Prevention and Treatment

Research exploring the effects of Avomine in conditions associated with systemic imbalance was conducted in Randomized Controlled Trials (RCTs), where healthy adult volunteers were observed in controlled settings. These studies, often double-blind and placebo-controlled, were used to examine patient-reported experiences related to specific motion challenges. Researchers primarily examined outcomes related to systemic or functional imbalance, such as motion sickness tolerance. Findings describe patterns observed in the studies regarding measured duration of exposure under certain testing conditions. This contributes to the understanding of symptom patterns.

Evidence for Use in Acute Nausea and Vomiting Management

Promethazine Theoclate was evaluated in RCTs and systematic reviews, particularly focused on Postoperative Nausea and Vomiting (PONV) in adult and some pediatric patients. These studies examined outcomes related to physical discomfort, specifically the frequency of vomiting and retching episodes and the scoring of nausea severity using patient-reported outcomes. Research explored short-term symptom changes following administration, and studies monitored outcomes related to episodic or acute changes such as the need for additional treatment. These study results reflect the specific conditions under which they were conducted.

Duration of Evidence: Acute and Long-Term Follow-up

The majority of the evidence is derived from short-term, acute observation periods, often focusing on effects within the first 4 to 24 hours post-administration or post-procedure. There is limited information for long-term outcomes describing the effects or durability of response for individuals using the medicine routinely over extended periods. Research exploring short-term changes provides context, but evidence describing maintenance data or prolonged use in observational settings evaluating outcomes reflecting daily functioning or activity level is not fully established.

Key Studies & References

  1. Promethazine - NIH StatPearls
  2. Promethazine: MedlinePlus Drug Information
  3. A Comparison of Two Differing Doses of Promethazine for the Treatment of Postoperative Nausea and Vomiting (PONV) - NYSPANA

Frequently Asked Questions (FAQ)

Common questions about Avomine (FAQ)

Q: How long does it usually take for Avomine to start working?

A: Official information indicates that the active substance in Avomine is generally well absorbed after it is taken by mouth. Clinical effects may begin to appear between 20 minutes and 2 to 3 hours after the tablet is ingested.


Q: How long do the effects of Avomine last after taking it?

A: According to official regulatory sources, the primary effects of the medicine often last for approximately four to six hours. However, the clinical effects may last longer, sometimes persisting for as long as 12 hours in some individuals.


Q: Is it normal to feel a bit dizzy after taking Avomine?

A: Yes, regulatory safety data lists dizziness or feeling unsteady on the feet as a possible side effect of the medicine. This is related to the way the drug works within the central nervous system. Dizziness is a factor that may affect daily activities.


Q: Does Avomine affect blood pressure?

A: Official safety data for Avomine notes the potential for hypotension (low blood pressure) as a possible cardiovascular side effect. This is particularly noted as a risk for older adults. Monitoring blood pressure is a safety consideration noted in official documents.


Q: Can I take Avomine if I have glaucoma?

A: Official drug labels state that conditions such as angle-closure glaucoma require caution and discussion before use. This is because Avomine has anticholinergic effects that may impact the eye. Official labeling indicates that conditions related to the eye, such as glaucoma, require caution and professional consideration before use.


Q: Are there warnings about Avomine and liver function?

A: Regulatory documents state that caution should be used if a patient has liver disease or hepatic impairment. This is because the liver plays a role in breaking down the medicine in the body. The status of liver function is a factor that requires professional consideration when using the medicine.


Q: Does Avomine affect fertility?

A: Official regulatory sources report that there is no evidence indicating that the active ingredient in Avomine affects fertility in either men or women.


Q: What should I do if I forget a dose of Avomine?

A: For the prevention of motion sickness, the official guidance states that a forgotten dose should be taken as soon as it is remembered. Official guidance advises against taking a double dose to make up for a forgotten dose.


Q: How is Avomine generally disposed of?

A: Official environmental guidelines strictly state that unused or expired medicines should not be disposed of via wastewater or household waste. Disposal requires consulting with a pharmacist to determine the appropriate method, such as a designated collection program.


Q: What kind of studies have been done on Avomine for its main uses?

A: Research on Avomine's effects has utilized controlled settings, including Randomized Controlled Trials (RCTs) and systematic reviews. These studies have primarily monitored patient-reported outcomes related to motion sickness tolerance and the severity of nausea and vomiting episodes.


Q: Is Avomine the same as other motion sickness tablets?

A: Avomine contains Promethazine Theoclate, which is classified as a First-generation H1 Receptor Antagonist and an Anti-emetic agent. This is one of several drug classes used to manage motion sickness, meaning it has a different chemical composition and mechanism of action compared to other types of motion sickness medicines.


Q: Can Avomine be taken for sickness that isn't travel-related?

A: Yes, official regulatory documents include the use of this medicine for the treatment of nausea and vomiting due to other causes beyond just motion sickness. The drug's anti-emetic action is applied to various sources of nausea.


Q: Are there different strengths of Avomine available?

A: While Avomine tablets are typically available in a 25 mg strength, the active substance, promethazine, is available in other strengths and dosage forms. These may include 12.5 mg and 50 mg tablets, or liquid forms, depending on the regulatory approval in your region.


Q: Are there restrictions on driving or operating machinery while taking Avomine?

A: Official product instructions advise caution regarding driving or operating machinery. Due to side effects such as dizziness, sleepiness, and confusion, patients are advised not to perform these tasks until they know they are not affected by the medicine's effects.


Q: Does Avomine contain gluten or lactose?

A: Official excipient lists for promethazine tablets often indicate the presence of lactose monohydrate as a non-active ingredient. Patients should check the specific patient information leaflet for details regarding gluten content in the excipients.


Q: Why is Avomine sometimes used as a sleep aid?

A: Avomine's mechanism involves sedative properties due to its action on certain brain receptors. Official labels note that a dose taken at bedtime can be used to induce a quiet sleep and relieve apprehension.


Q: Is there a risk of dependence or addiction with Avomine?

A: Regulatory sources address the general concern that misuse of sedative medicines can lead to psychological dependence. The potential for dependence is a topic requiring professional consideration.


Q: What is the legal classification of Avomine (e.g., prescription-only or over-the-counter)?

A: The availability of Avomine varies depending on the country. In some regions, official patient leaflets confirm the product is available to purchase without a prescription (over-the-counter), while in others, it may require a prescription.


Q: Can Avomine be split in half if the tablet is scored?

A: Official administration guidelines for children's dosing mention using half a tablet, suggesting that the tablet form is designed to be divided. Some regulatory labels confirm that promethazine products are scored to allow for breaking.


Q: Does taking Avomine prevent vomiting?

A: Yes, Avomine is officially described as an anti-emetic drug, which means it works to prevent and treat nausea and vomiting. Its mechanism is to raise the threshold required to activate the body’s involuntary vomiting reflex.


Q: Is it true that Avomine is sometimes used for vertigo?

A: Yes, official prescribing information explicitly states that the medicine is used to help prevent and treat symptoms including vertigo (a sensation of spinning or giddiness). It addresses this by modulating signals related to balance.


Q: What is the maximum number of days I can continuously take Avomine for travel sickness?

A: Official regulatory guidelines specify that the medicine should generally not be taken for more than seven days when it is used for travel sickness. Use beyond this timeframe is a topic requiring professional consideration.


Q: Can I take Avomine if I have a history of seizures?

A: Official labels advise that Avomine may lower the seizure threshold and should therefore be used with caution in individuals who have a history of seizure disorders. The use of Avomine in persons with seizure disorders is a safety factor requiring professional consideration.


Q: What are the official recommendations on taking Avomine for sea sickness?

A: Official recommendations for Avomine are provided for general motion sickness, and these guidelines are typically applied to specific environments like sea or air travel. The drug should be taken ahead of time, as described in the administration instructions.


Q: Is Avomine known to affect sleep quality?

A: Because the drug's primary side effect is sedation and it is sometimes used to induce a quiet sleep, it will affect sleep patterns. These sedative properties are directly related to its classification as a potent CNS depressant.

How should Avomine be stored and disposed of?

How to Store and Dispose of Avomine (Promethazine Theoclate)

Official regulatory guidelines strictly define the necessary storage and disposal procedures for Avomine to maintain its quality and ensure safety.

Storage Requirements

  • Temperature and Light: Avomine tablets must be stored below 30 C and protected from light. Always keep the medicine in its original container.
  • Child Safety: It is mandatory to keep this medicine out of the sight and reach of children.
  • Stability: Do not use the tablets after the expiry date printed on the pack.

Disposal Instructions

  • Waste Route: Medicines should not be disposed of via wastewater or household waste as defined by official environmental standards.
  • Procedure: To dispose of unused or expired Avomine, you must consult your pharmacist, as returning the medicine to a designated collection point helps protect the environment.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

Available in countries:

Equivalent of Avomine found in:

A-Z Index: