Gastrum

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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 Gastrum

Gastrum is a synthetic pharmaceutical preparation intended to manage conditions linked to excessive acidity in the stomach and digestive tract. Its identity is defined by the sole active chemical substance, Famotidine. This medicine belongs to the pharmacological class of histamine H2-receptor antagonists, commonly known as H2-blockers, which are acid-suppressing agents.


Quick Facts

Property Description
Active ingredient Famotidine
Pharmacological class Histamine H2-receptor antagonist
Forms Oral tablet, Oral suspension, IV solution
Common use Reduction of gastric acid secretion
Origin Synthetic organic compound

What Type of Medicine is Gastrum?

Gastrum is classified as a histamine H2-receptor antagonist (or H2-blocker) and is a single-ingredient product containing only the active compound Famotidine. Famotidine functions as a competitive inhibitor of histamine at the H2-receptors of the parietal cells. Gastrum is typically positioned as an over-the-counter (OTC) acid reducer, making it readily accessible for common, acute episodes of acid discomfort associated with self-care. Famotidine itself is a synthetic organic compound, ensuring its production is standardized and its pharmacological properties are predictable.


Understanding the Forms and Origin of Gastrum

The medicine is available in various pharmaceutical preparations to accommodate different patient needs and routes of administration. The most common form is the oral tablet, designed to be swallowed, which allows for convenient self-administration. Unlike certain prescription forms, Gastrum often utilizes a specific small, easy-to-swallow tablet design for the consumer market. For critical care or when oral administration is not feasible, the same active substance, Famotidine, is also prepared as a sterile intravenous (IV) solution for use under medical supervision. The use of both oral and intravenous forms ensures that treatment can be initiated flexibly, based on the urgency of the clinical situation.


What is the General Purpose of Famotidine?

The general purpose of Famotidine is to function as an acid suppressant by reliably and predictably reducing gastric acid secretion. This mechanism leads to a stabilization of the stomach environment. The primary benefit of this action is the relief of discomfort and irritation caused by overly corrosive acid levels in the upper digestive tract, such as that experienced after consuming trigger foods. Famotidine is designed to suppress both nocturnal and daytime acid production, distinguishing its action from less potent alternatives. The medication is intended for reliable, sustained acid control when needed.

Regulatory References

  1. Famotidine - MedlinePlus Drug Information

What side effects are possible with Gastrum?

Possible side effects and safety information

The safety profile of Gastrum (Famotidine) is formally documented by regulatory authorities, classifying documented adverse effects by frequency and the physiological system affected. The following summaries are strictly based on government-approved product information.

Officially Documented Adverse Reactions by Frequency

Adverse reactions are classified into frequency tiers derived from clinical trial data and post-marketing surveillance:

Frequency Classification Affected System-Organ Class Documented Effects
Common (ge 1/100 to <1/10) Nervous System, Gastrointestinal Headache, Dizziness, Constipation, Diarrhea
Uncommon (ge 1/1,000 to <1/100) Multiple Systems Nausea, Vomiting, Abdominal discomfort, Flatulence, Fatigue, Rash, Pruritus, Urticaria

Serious Adverse Reactions and Population-Specific Safety

Certain effects are classified as Very Rare (<1/10,000) and include serious events spanning multiple systems. Documented serious adverse reactions include severe hypersensitivity reactions (such as anaphylaxis), blood dyscrasias (like agranulocytosis), hepatitis, and severe dermatologic events (SJS/TEN). Effects on the heart, such as arrhythmias and QT prolongation, have also been reported.

Regulatory labeling highlights specific safety considerations for certain patient populations. Older adults and individuals with moderate to severe renal impairment are noted for an increased risk of Central Nervous System (CNS) adverse reactions, including confusion and delirium, due to reduced drug clearance. A fundamental safety constraint is the requirement to rule out gastric malignancy prior to use, as symptom relief may mask a serious underlying condition. The medicine is contraindicated in patients with a history of serious allergy to Famotidine or other H2-receptor antagonists.

Overdose and Emergency Response

Overdose and when to seek help

Official regulatory documents define the overdose profile of Famotidine by documenting specific risks and mandated emergency actions.


Documented Overdose Manifestations

Overdose may present with serious manifestations similar to known adverse reactions, primarily affecting the Central Nervous System (CNS) and Cardiovascular System. CNS effects include confusion, disorientation, agitation, hallucinations, and lethargy. Serious outcomes may involve seizures and cardiac abnormalities such as QT prolongation and arrhythmias.

Population-Specific Risk: Regulatory labeling specifies that patients with renal impairment are at a significantly higher risk for these severe CNS and cardiac events due to reduced drug clearance. Elderly patients are also noted to be more susceptible to CNS disturbances.


Required Emergency Actions

The most critical action mandated by regulatory authorities is to seek medical help right away in case of any suspected overdose. Specifically, contact a Poison Control Center immediately. Emergency services must be contacted if the affected individual has collapsed, is experiencing a seizure, or has difficulty breathing.

Official Management: No specific antidote is documented for Famotidine overdose. Management relies on symptomatic and supportive treatment, including clinical monitoring of vital signs and ECG, and employing measures to remove unabsorbed material from the gastrointestinal tract.

Therapeutic Uses of Gastrum

Therapeutic Indications and Benefits

Gastrum is a pharmaceutical formulation containing aluminum hydroxide and magnesium hydroxide. These active ingredients are categorized as antacids, which are primarily used to manage symptoms associated with gastric acidity and related gastrointestinal conditions.

Main Uses

Gastrum is indicated for the relief of symptoms in the following conditions:

  • Gastric and Duodenal Ulcers: It helps alleviate the discomfort and burning sensations associated with peptic ulcer disease.
  • Gastritis: It is used to manage acute or chronic inflammation of the stomach lining.
  • Gastroesophageal Reflux: The medication provides relief from heartburn and acid regurgitation.
  • Hiatal Hernia: It is used to manage the symptomatic acid reflux often associated with this structural condition.
  • Hyperchlorhydria: It treats excessive secretion of hydrochloric acid in the stomach.

Clinical Benefits and Mechanism of Action

The primary benefit of Gastrum is its ability to neutralize existing gastric acid. It works through a chemical reaction in the stomach that lowers the acidity level of the gastric juice. Unlike some other treatments, antacids like aluminum and magnesium hydroxide do not prevent the production of acid but rather act on the acid already present.

  • Symptom Relief: By raising the gastric pH, Gastrum helps reduce the irritation of the esophageal and gastric mucosa, leading to a decrease in pain and burning sensations.
  • Mucosal Protection: By neutralizing acid and partially inhibiting the activity of pepsin (a digestive enzyme), the medication helps create a more favorable environment for the natural healing of the stomach and intestinal lining.
  • Balanced Action: The combination of aluminum hydroxide and magnesium hydroxide is designed to balance gastrointestinal effects. Aluminum compounds alone may have a constipating effect, while magnesium compounds can have a laxative effect; when used together, they aim to maintain normal bowel function during treatment.

Regulatory References

  1. NIH MedlinePlus overview of H2 blockers

Eligibility and Restrictions for Use

Who can and cannot use Gastrum (Famotidine)

Famotidine is an acid-suppressing agent with strict population-eligibility rules defined by regulatory authorities.

The medicine is contraindicated for patients with a history of serious hypersensitivity reactions (allergy) to Famotidine or any other Histamine H2-receptor antagonist. Oral tablet forms containing lactose are also contraindicated in patients with rare hereditary problems such as galactose intolerance.


Population Status Eligibility Restriction
Age-Related Use Adults are approved for use. OTC use is approved for ages 12 years and older; use is not established in children under 12. Use in neonates may be restricted depending on the specific formulation.
Organ Function Use is restricted in patients with moderate to severe renal impairment (kidney disease) and requires adjustment to the daily dose due to the drug's elimination. Hepatic impairment does not typically require dosage change.
Conditional Use Pregnancy: Use is recommended only if clearly needed. Lactation: A decision must be made to discontinue nursing or the drug. The absence of gastrointestinal malignancy must be confirmed before treatment for gastric ulcers.

Older adults experiencing delirium should not be administered this medication.

What should I know about interactions with other medicines?

Interactions with other medicines and products

The interaction profile of Gastrum (Famotidine) is largely structured by its documented effects on gastric pH and drug clearance pathways. This section details interaction-related restrictions and requirements as stated in government regulatory documents.

Category Officially Documented Interaction Requirement
Formally Contraindicated Combination Co-administration is formally contraindicated with specific anti-retroviral regimens, such as Atazanavir/Ritonavir combined with Tenofovir, in some regulatory documents.
pH-Dependent Drug Exposure Famotidine's acid-reducing effect may significantly reduce the systemic exposure (AUC/Cmax) of certain co-administered drugs that require stomach acid for proper absorption (e.g., specific antifungals, HIV medications, and tyrosine kinase inhibitors).
Exposure-Altering Co-administration Co-administration with Tizanidine is advised to be avoided as it may lead to substantial increases in Tizanidine blood concentrations. The use of Probenecid is also avoided, as it inhibits Famotidine's renal tubular secretion, increasing Famotidine plasma concentrations.
Timing Requirements Sucralfate should not be administered within two hours of the Famotidine dose, as it inhibits Famotidine absorption. Specific acid-dependent medications may also require separation in administration timing.
Population-Specific PK Note Patients with moderate or severe renal impairment may experience a higher systemic exposure of Famotidine due to reduced clearance, which is associated with an increased risk of Central Nervous System adverse reactions.

Co-administration with food or alcohol is documented in regulatory sources as having no clinically significant effect on Famotidine blood levels.

Mechanism of Action

Gastrum operates through a selective pharmacodynamic mechanism targeting bone cells. The molecule exerts its primary action by binding with high affinity to the VAP-1 receptor, which is expressed specifically on the surface of active osteoclasts. This targeted molecular interaction acts as a downstream signal modulator. Specifically, the receptor occupancy initiates an intracellular cascade that results in a measurable reduction in the catalytic activity of the c-Src kinase pathway within the osteoclast. The diminished activity of this specific kinase pathway is mechanistically critical, as it directly impacts the cell's cytoskeleton organization and signaling required for bone degradation. Consequently, Gastrum effectively modulates the overall resorptive function of the osteoclast. This molecular action ultimately influences the physiological bone remodeling rate by shifting the balance between bone formation by osteoblasts and resorption by osteoclasts, achieving modulation at the cellular and tissue level.

Dosage and Administration Information

How to Use Gastrum (Famotidine) — Official Administration Guidelines

Gastrum is administered according to standardized regimens focusing strictly on the appropriate route, dose, and frequency.

Administration Scope

Category Official Administration Instructions
Approved Administration Routes The medication is approved for oral use, available as tablets or a reconstituted suspension, and for intravenous (IV) injection or infusion. IV administration is typically reserved for hospitalized adults unable to tolerate oral intake.
Standard Adult Dosing The typical dose for active gastrointestinal conditions is 20 mg twice daily or 40 mg once daily at bedtime. For pathological hypersecretory conditions, dosing may start at 20 mg every six hours, potentially increasing up to 160 mg every six hours.
Timing in Relation to Meals Oral doses of Famotidine may be taken with or without food. When used for the prevention of episodic heartburn (OTC dose), it should be administered 10 to 60 minutes before consuming a meal or beverage known to cause symptoms.
Course Duration Patterns Treatment duration varies by condition: acute treatment for ulcers or GERD is typically limited to 6 to 12 weeks. Self-treatment with over-the-counter strengths should not exceed 14 days without medical oversight.

Population-Specific Use and Preparation

Dosage adjustments are specifically mandated for patients with impaired renal function. For individuals with creatinine clearance of le 50 mL/min, the official instruction is to either reduce the dose by 50% or extend the dosing interval to 36 to 48 hours to prevent accumulation of the substance. Age alone does not typically require a dose change. The IV solution must be diluted with a compatible agent before being administered as a slow injection over at least two minutes or an infusion over 15 to 30 minutes.

These official instructions define the procedural steps for using Gastrum, ensuring that administration is performed regarding amount, timing, and patient-specific modifications.

Recent Clinical Evidence

The evidence base for Gastrum (Famotidine) has been developed through controlled scientific research, primarily focusing on what the studies observed in conditions characterized by acid-related discomfort. The research available includes Randomized Controlled Trials (RCTs), which compare the medicine against a placebo or another treatment, along with systematic reviews that combine the findings of multiple studies.


Evidence for Acute Heartburn and Indigestion Relief

Research exploring relief for episodic heartburn and acid indigestion symptoms often uses short-term RCTs. Researchers examined patient-reported outcomes, such as the time it took for participants to report complete relief from heartburn pain, and whether taking the medicine before a meal was observed in studies examining symptom prevention. Studies reported measurements showing patterns in symptom resolution when compared to a placebo. The results apply only to the populations studied and are primarily focused on the acute response.


Research on Gastroesophageal Reflux Disease (GERD) and Esophagitis

Gastrum was studied for its role in clinical contexts involving GERD and erosive esophagitis. The evidence is derived from intermediate-term clinical trials that utilized objective measures, such as endoscopy, to monitor physiological strain on the esophageal lining. Trials reported measurements showing the proportion of participants who achieved healing of esophageal erosions. Long-term effects are not fully established beyond the typical 8 to 12-week treatment protocols. Additionally, evidence comparing the medicine to all available treatment standards remains limited.


Key Uncertainties and Research Gaps

Despite the established research base, several key limitations are documented. The evidence contributes to understanding short-term changes and the initial observed response pattern. However, there is limited information for long-term outcomes regarding the continued effect or durability of response over many years. This pattern is a documented research limitation regarding the data available for long-term outcomes for this medicine.

Key Studies & References

  1. Meta-analysis: the efficacy of over-the-counter gastro-oesophageal reflux disease therapies (Cochrane Review)
  2. Famotidine - StatPearls - NCBI Bookshelf (Authoritative Clinical Review)

Frequently Asked Questions (FAQ)

Common questions about Gastrum (FAQ)


Q: Can Gastrum cause feelings of tiredness or fatigue?

According to official safety information, fatigue has been documented as an uncommon adverse reaction associated with Gastrum use. An uncommon reaction is defined as being reported in less than 1 in 100 people. This information is based on data collected during clinical trials and post-marketing surveillance, consistent with official product labeling.


Q: Can taking Gastrum make you more sensitive to the sun?

Official regulatory documents indicate that photosensitivity, which is a heightened skin reaction to sunlight, has been reported as a rare side effect of Gastrum. This is not a common reaction, but official information documents this potential for light sensitivity.


Q: Is it normal to feel a change in appetite while using Gastrum?

A diminished appetite has been reported as an adverse reaction in some drug safety data, although this is not described as a common effect. Regulatory safety documents mention this potential change based on collected reports.


Q: Can Gastrum cause dry mouth or changes in vision?

Official safety data includes blurred vision as a rare adverse reaction. Dry mouth has also been reported in post-marketing data. These are documented in regulatory sources but are not among the most frequently observed side effects.


Q: Does Gastrum have a risk of affecting kidney or liver function?

Hepatitis, a potential effect on the liver, is stated in official documents to be a very rare adverse reaction. Furthermore, regulatory prescribing information references the need for dose adjustments in individuals with moderate or severe renal impairment due to reduced drug clearance.


Q: Is there a maximum time recommended for continuous use of Gastrum?

Official prescribing information details specific treatment durations based on the condition being addressed. For example, over-the-counter use is generally limited to 14 days, while acute prescription treatments may last up to several weeks. The intended course of treatment varies widely and is detailed in the official product information.


Q: What happens if a person misses a dose of Gastrum?

Official patient instructions generally indicate that a missed dose is taken as soon as the person remembers. However, if it is almost time for the next scheduled dose, official instructions indicate that the missed dose is typically skipped to maintain the intended dosing interval.


Q: How long does it typically take for people to notice the effects of Gastrum?

Studies and official information indicate that the onset of the acid-suppressing effect is generally reported to occur within an hour after administration. This timeline refers to when the chemical action begins to predictably reduce stomach acid.


Q: Are there any common long-term concerns associated with Gastrum?

Official research summaries note that the available evidence is primarily focused on short-term use, typically up to 12 weeks. Because of this, regulatory documents acknowledge limitations regarding the availability of long-term outcome data and concerns related to outcomes beyond the documented study periods.


Q: Is it true that Gastrum can affect birth control pills?

Regulatory interaction studies have been conducted and found no clinically significant pharmacokinetic interaction between Famotidine (Gastrum's active ingredient) and commonly used hormonal contraceptives. Official documents do not indicate that Gastrum affects the efficacy of these medications.


Q: Do older adults typically need a different level of monitoring when using Gastrum?

Official safety information notes that older adults may be at increased risk of Central Nervous System (CNS) adverse reactions, such as confusion or delirium. This is due to the potential for reduced drug clearance in this population, a factor recognized in regulatory documentation.


Q: Is Gastrum appropriate for use in children under a certain age?

Over-the-counter use of Gastrum is approved for individuals 12 years of age and older. For children younger than 12, the use of this medicine is not generally established or is restricted, depending on the specific formulation.


Q: What is the current status of research regarding Gastrum's long-term safety?

Research summaries consistently indicate that the available evidence focuses on short-term use. Consequently, official documents note that there are documented limitations regarding the availability of data on long-term safety and efficacy beyond the typical treatment courses.


Q: Why do official documents sometimes list multiple uses for Gastrum?

Official drug documents describe multiple indications for use, such as the treatment of duodenal ulcers, gastroesophageal reflux disease (GERD), and pathological hypersecretory conditions. These distinct uses are listed because evidence supporting them has been presented to and approved by regulatory bodies.


Q: Are there specific times of day that Gastrum is generally intended to be taken?

Official dosing regimens allow for flexibility, including administration twice daily or once daily. The once-daily option is often specified as being taken at bedtime. The intended time may vary based on the reason the medicine is being used.


Q: Have any studies looked into Gastrum's impact on mood or sleep?

Official documentation lists Central Nervous System (CNS) effects, such as dizziness and confusion, as reported adverse reactions. These potential effects are a documented part of the drug's known safety profile.


Q: Why might a person need to get blood tests while taking Gastrum?

Blood dyscrasias (a rare disorder affecting blood cell formation) are documented as very rare adverse reactions associated with the drug. Additionally, blood tests may be performed to monitor kidney function, which is necessary because regulatory prescribing information references the need for dose adjustments in patients with renal impairment.

How should Gastrum be stored and disposed of?

How to Store and Dispose of Gastrum (Famotidine)

Gastrum (Famotidine) must be stored at controlled room temperature, defined as 20°C to 25°C (68°F to 77°F). The product should be kept in its original, tightly closed container and protected from moisture. It must not be frozen. To maintain child safety, the medication must be stored out of the sight and reach of children.

Disposal Instructions

For unused or expired product, a drug take-back program is the recommended disposal method. Famotidine should not be discarded in household trash or by flushing it down the toilet, unless the specific formulation is designated for flushing by official guidance. The reconstituted oral suspension is only stable for 30 days and must be discarded thereafter.

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

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