Avomit

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Medically reviewed

Rosario Oropesa

Last updated on 22/12/2025

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 Avomit

Property Description
Active Ingredient Letrozole (INN)
Form Oral Tablet (Solid Dosage Form)
Pharmacological Class Aromatase Inhibitor (Third Generation)
General Purpose Systemic Hormonal Control
Origin Synthetic, Nonsteroidal Compound

Avomit is a prescription-only medication containing the active ingredient Letrozole, which is defined as a non-steroidal aromatase inhibitor and antineoplastic agent. The drug is used for systemic hormonal therapy, a strategy clinically recognized for its role in influencing hormone levels throughout the body. The active compound, Letrozole, is a bis-triazole derivative, a structure that distinguishes its specific and efficient targeting of the aromatase enzyme system.

Defining Avomit: Identity and Pharmacological Class

The core identity of this drug lies in its active component, Letrozole, which is categorized within the class of aromatase inhibitors. Letrozole belongs to the pharmacological group that suppresses estrogen synthesis. This indicates that the medication's primary function is to block the body’s pathway for producing estrogen. As a third-generation inhibitor, Letrozole is specifically recognized for achieving high selectivity in this therapeutic approach.

Composition, Origin, and Dosage Form

Avomit is formulated as a single-active-ingredient product using the synthetic compound Letrozole. This synthetic origin ensures chemical consistency, contrasting with medications derived from natural sources, a standard feature of modern pharmaceuticals. The drug is presented as a solid oral dosage form, specifically an oral tablet for ease of swallowing, establishing its route of administration. The composition necessarily includes the active ingredient alongside various solid oral dosage form excipients, such as binders and fillers, required for the tablet’s stability and controlled absorption.

General Purpose of Aromatase Inhibition

The overarching purpose of this pharmacological class is to provide systemic control over conditions reliant on estrogen for stimulation and progression. The primary function involves estrogen synthesis suppression, where the drug blocks the aromatase enzyme, which is responsible for converting androgen hormones into estrogen in tissues throughout the body. This action significantly reduces the level of circulating estrogen. By removing this significant hormonal stimulus, Avomit serves as a foundational component in strategies requiring hormonal control to stabilize hormone-sensitive processes, particularly in postmenopausal women.

Regulatory References

  1. NCI Hormone Therapy Fact Sheet

What side effects are possible with Avomit?

Possible side effects and safety information

The safety profile of Avomit (Letrozole) is established through regulatory documentation that strictly defines adverse reactions based on their frequency and the physiological systems affected.

Frequency-Classified Adverse Reactions

Adverse effects are categorized by occurrence rates observed in clinical settings, ranging from Very Common to Rare. Very Common effects (affecting more than 1 in 10 users) include hot flushes, fatigue (asthenia), arthralgia (joint pain), and hypercholesterolaemia. Common effects (1 to 10 in 100 users) often involve the nervous system (headache, dizziness), gastrointestinal system (nausea, constipation), and skin (rash, increased sweating), in addition to bone pain and weight increase.

System-Organ Classes and Serious Reactions

Side effects are officially grouped into System-Organ Classes, notably affecting Musculoskeletal and Connective Tissue Disorders, Metabolism and Nutrition Disorders, and General Disorders. Documented serious adverse reactions are generally uncommon or rare but include clinically significant events such as thromboembolic events (e.g., arterial thrombosis and pulmonary embolism).

Population and Duration Safety Constraints

Regulatory documentation establishes specific constraints on the use of this medication. Avomit is contraindicated in women with pre-menopausal status, during pregnancy, and while lactating. Safety considerations are also noted for patients with severe hepatic impairment. Furthermore, risks tied to duration of use are documented: effects related to prolonged oestrogen deprivation, such as an increased risk of osteoporosis and bone fracture, are associated with long-term exposure, while transient vaginal bleeding is noted to occur most frequently during the initial weeks of treatment.

Overdose and Emergency Response

When an overdose of Avomit (Letrozole) is suspected, immediate medical attention must be sought. Official regulatory information states that no specific antidote is known for this compound. Due to the absence of a reversing agent, the required management approach focuses entirely on providing symptomatic and supportive care.

Documented case reports indicate that acute single ingestions of the active ingredient, including doses up to 62.5 mg (equivalent to 25 standard tablets), have occurred without resulting in serious adverse reactions. While this level of exposure has been recorded, the official profile emphasizes the necessity of prompt medical observation for any overdose scenario.

During treatment, procedures may include the administration of activated charcoal or the controlled induction of emesis, provided the patient is alert. Continuous observation is mandatory, requiring the frequent monitoring of vital signs. For symptomatic patients, further medical assessment includes monitoring the complete blood count (CBC) and Liver Function Tests. Special consideration is given to monitoring the fluid and electrolyte status if the patient exhibits significant vomiting or diarrhea. This rigorous, regulator-mandated observation ensures all potential clinical changes are managed under professional medical supervision.

Therapeutic Uses of Avomit

Avomit (Letrozole) is commonly used in postmenopausal women for managing Hormone Receptor-Positive (HR-positive) breast cancer. Its therapeutic focus is on systemic disease control rather than addressing immediate, transient symptoms.

The medication is relevant across multiple therapeutic settings: it is applied as adjuvant therapy after primary local treatment to manage the risk of cancer recurrence, used for advanced or metastatic disease to control progression, and sometimes employed as neoadjuvant therapy before surgery to manage the size of the tumor.

The primary benefit supports the patient by easing the overall disease burden and supports general well-being during symptomatic phases in cases of hormone-sensitive malignancy. This medication is typically part of a long-term strategy, offering support that helps manage the systemic risks associated with a hormone-driven condition.


Quick Fact: Support for Systemic Disease Burden Avomit assists with managing conditions where symptoms are related to systemic imbalance and malignant disease progression, providing support that assists with maintaining functional stability during difficult episodes.

Eligibility and Restrictions for Use

Who Can and Cannot Use Avomit? (Letrozole)

The official eligibility criteria for Avomit (Letrozole) are strictly defined by regulatory documents, primarily restricting its use to adult women who are postmenopausal.


Eligibility Status

Classification Population Group Constraint Basis
Contraindicated Pregnancy; Lactation Risk of fetal harm; unknown risk to infant [NIH DailyMed; FDA Label]
Contraindicated Premenopausal Women Confined to postmenopausal endocrine status [Medsafe Data Sheet]
Restricted Use Severe Hepatic Impairment Requires dose modification and close supervision [FDA Label]
Not Recommended Pediatric Patients Safety and efficacy are not established in this age group [EMA SmPC]

Resulting Eligibility Structure

Official eligibility statements confirm the medicine is contraindicated for pregnant women, breastfeeding women, and those with premenopausal endocrine status. While use is permitted in older adults, it is not recommended for the pediatric population. Eligibility is conditional on the patient's physiological status, with restricted use applied in cases of severe hepatic impairment and caution advised for patients with existing osteoporosis [MHRA SmPC].

What should I know about interactions with other medicines?

Interactions with other medicines and products

The use of Avomit (Domperidone) with certain other medicines is contraindicated due to the risk of serious cardiac events, specifically the prolongation of the heart's QT interval, which can lead to ventricular arrhythmia. This risk is primarily managed through two key interaction categories:

Contraindicated Combinations

  • Strong CYP3A4 Inhibitors: Medicines that strongly inhibit the CYP3A4 enzyme should not be taken with Avomit. These drugs can significantly increase the concentration of Avomit in the bloodstream, leading to a heightened risk of heart rhythm problems. Examples include certain antifungal medicines (e.g., ketoconazole) and certain antibiotics (e.g., clarithromycin, erythromycin).
  • QT-Prolonging Medicines: Co-administration with any other medicinal product known to prolong the QT interval is also contraindicated. This includes specific antiarrhythmics, certain antipsychotics, some antidepressants (like citalopram), and certain antibiotics (like moxifloxacin).

Other Relevant Interactions

Concomitant use with other medications requires caution. For example, medicines with anticholinergic properties may counteract the prokinetic (movement-enhancing) effect of Avomit. Additionally, Avomit may interfere with the intended effects of dopaminergic ergot alkaloids, such as those used in Parkinson's disease treatment. The use of Avomit in patients with underlying cardiac conditions, electrolyte imbalances, or moderate to severe liver impairment is also subject to specific warnings and is often contraindicated.

Mechanism of Action

The drug Avomit (Domperidone) exerts its action by functioning as a selective Dopamine D2 and D3 receptor antagonist. Its primary mechanism involves two distinct anatomical areas.

Modulation of Chemoreceptor Trigger Zone

Avomit engages D2 and D3 receptors located in the chemoreceptor trigger zone (CTZ), a region of the brainstem outside the blood-brain barrier. Antagonism at this site blocks the effect of circulating dopamine. This initiates a signaling sequence that modulates the transmission of afferent signals toward the central vomiting center, thereby influencing the threshold for activation of the emetic reflex.

️ Enhancement of Gastrointestinal Peristalsis

Additionally, the drug interacts with peripheral D2 receptors within the walls of the upper gastrointestinal tract. This antagonism modifies localized molecular steps that facilitate the enhanced release of acetylcholine from myenteric neurons. This engagement results in altered gastrointestinal motility parameters, including increased esophageal peristalsis, enhanced lower esophageal sphincter pressure, and an accelerated rate of gastric emptying through augmented antral and duodenal movement.

Dosage and Administration Information

How to Use Avomit: Administration Guidelines

Avomit (Letrozole) is administered as an oral tablet and must be used according to standardized procedures. The established usage protocol ensures consistent systemic delivery of the active compound.

Standard Dosing and Administration

The standard and maximum recommended dose for Avomit across all approved indications is 2.5 mg. The drug is taken once daily as a continuous regimen and is structured for long-term use. The oral tablet must be swallowed whole; it should not be crushed or chewed.

Administration is flexible concerning mealtimes, as the tablet may be taken with or without food. The standard practice is to take the dose at approximately the same time every day to maintain a consistent schedule.

Duration and Special Dosing Conditions

The duration of treatment is context-dependent, typically continuing for five years in the adjuvant setting or continuing until disease progression in advanced cases.

For most patient groups, including older adults (65 years and older) and those with renal impairment (creatinine clearance ≥ 10 mL/min), no dose adjustment is required. A specific modification is recommended for patients with severe hepatic impairment (Child-Pugh C), where the dosage is reduced to 2.5 mg every other day.

If a dose is missed, it should be skipped if it is almost time for the next scheduled dose. Standard protocol indicates not to take a double dose to compensate for the missed administration.


Administration Scope Instruction or Pattern
Route of Administration Oral route only.
Frequency Pattern Once daily (continuous).
Missed-Dose Rule Skip the missed dose if the next dose is due soon; do not double dose.

Recent Clinical Evidence

Research evidence / Overview of Studies for Avomit

The research base for Avomit (Letrozole) consists primarily of large, international Randomized Controlled Trials (RCTs), the method relied upon for regulatory evaluation. These trials were designed to explore the use of the medicine across different stages of hormone receptor-positive breast cancer in postmenopausal women. The studies monitored specific outcomes, such as how long patients remain free of disease recurrence and overall survival time.


Evidence for Use After Initial Treatment (Adjuvant Setting)

Research was conducted using large-scale RCTs, such as the BIG 1-98 study, to compare five years of Letrozole treatment against five years of Tamoxifen or sequential regimens. The primary outcomes examined were long-term disease status measures, including Disease-Free Survival and Overall Survival. Studies reported measurements of a Disease-Free Survival outcome when comparing Letrozole with Tamoxifen monotherapy. Updated reports and adjusted analyses described measurements of Overall Survival across the comparison arms.

What remains uncertain is the long-term, pure comparison of Overall Survival between the two treatments. The initial trial design included a provision for patients to switch treatments (crossover), which complicates the statistical interpretation of the survival data.


Evidence for Extended Treatment (Extended Adjuvant Setting)

Studies were conducted in postmenopausal women who had completed about five years of initial hormonal therapy. The research involved large, randomized, placebo-controlled trials which compared taking an additional five years of Letrozole versus taking an inactive placebo. The outcomes monitored were Disease-Free Survival and Overall Survival over this extended treatment period. The trials reported measurements of Disease-Free Survival outcomes when comparing the Letrozole group versus the placebo group. Analysis reported measurements of the Overall Survival outcome in a specific subgroup: those who were initially diagnosed with node-positive disease.


What Research Gaps and Uncertainties Exist

Certainty remains low regarding the direct interpretation of Overall Survival in some trials due to the complexity introduced by patients switching treatment arms. Furthermore, there is limited information for long-term outcomes regarding non-cancer related effects, such as the cumulative impact on bone health and cardiovascular events. Subgroup findings are uncertain or lacking for certain specific comorbidities, and continuous monitoring is required to better understand the full range of effects in diverse patient groups.

Frequently Asked Questions (FAQ)

Common questions about Avomit (FAQ)

Q: How should I take this medication? With or without food?

Official product information states that Avomit can be taken orally with or without food. It is important to follow the specific administration instructions provided by your healthcare provider or included in the package leaflet.


Q: Can I drive or operate machinery while taking this?

According to regulatory documents, this medication may cause side effects such as dizziness and sleepiness. Regulatory information advises against driving a car or operating heavy machinery until you are aware of how Avomit affects your ability to perform these tasks.


Q: Will I gain weight from this medication?

Regulatory information indicates that weight gain is a reported side effect of this medication. It is listed among the common adverse reactions reported in adult clinical trials, occurring in 5% or more of patients at a rate higher than placebo.


Q: Can I drink alcohol while taking this?

Official safety information states that alcohol should not be consumed while taking this medication. Alcohol can interact with the drug and increase the risk of side effects such as excessive sleepiness and dizziness.


Q: What happens if I stop taking the medicine suddenly?

Regulatory safety information warns that abrupt or rapid discontinuation of Avomit may increase the risk for seizures in some patients, and withdrawal symptoms have also been observed. The product labeling states that the drug should be tapered, or gradually reduced, over a period of at least one week.


Q: What is the half-life of this drug?

Based on official pharmacokinetic data, the mean elimination half-life of Avomit in people with normal kidney function is 6.3 hours. The half-life is a measure of how long it takes for half of the drug to be removed from the body.


Q: Can children 2 years old use it?

Regulatory documents state that this medication is indicated for the treatment of partial-onset seizures in pediatric patients who are 1 month of age and older. Use for other conditions in children of this age falls outside the official indications.

How should Avomit be stored and disposed of?

How to Store and Dispose of Avomit

Avomit (Letrozole) tablets must be stored according to official regulatory specifications to maintain product integrity.


Storage Requirements

  • Temperature: Store at Controlled Room Temperature, typically 20 C to 25 C (68 F to 77 F). Do not store above 30 C (86 F) and do not refrigerate or freeze.
  • Protection: Keep the tablets protected from moisture and excess heat.
  • Packaging: The medicine must be kept in the original, tightly closed container or blister pack.
  • Child Safety: Avomit must be stored out of the sight and reach of children at all times.

Disposal Instructions

Unused or expired Avomit should be disposed of through a drug take-back program or returned to a pharmacy.

  • Prohibition: The medicine must not be thrown into household trash or flushed down the toilet or sink, as this prevents environmental contamination.

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

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