Altacid

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Altacid

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Medically reviewed

Marina Burgos

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 Altacid

Property Description
Active ingredients Aluminium Hydroxide, Magnesium Hydroxide
Form Oral suspension, chewable tablets
Pharmacological class Non-systemic antacid
Common use Symptomatic relief of gastric hyperacidity
Origin Synthetic inorganic compounds

Altacid is a combination pharmaceutical preparation classified as a non-systemic antacid, designed to neutralize excess acid in the stomach and relieve symptoms of gastric hyperacidity. The active components exert a direct, localized action within the gastrointestinal tract, ensuring focused relief without being absorbed into the systemic circulation. This approach is clinically recognized for its ability to provide immediate comfort for acute instances of acid reflux.

What Type of Medicine is Altacid?

Altacid is categorized as an antacid, a type of gastrointestinal agent specifically employed to buffer or reduce the acidity of gastric secretions. This distinction confirms the medicine works by immediate chemical neutralization, setting it apart from drugs that biologically suppress acid production. Altacid, as a typical example of this formulation, is often positioned for adult patients seeking accessible, over-the-counter (OTC) solutions when dealing with heartburn.

Composition and Available Forms of Altacid

The effectiveness of Altacid is founded on its dual-salt composition, primarily consisting of Aluminium Hydroxide and Magnesium Hydroxide, which are synthetic inorganic compounds. These hydroxides are basic compounds that react with hydrochloric acid in the stomach to increase the pH level, thereby mitigating acid-related discomfort. Altacid is conveniently administered via the oral route and is manufactured both as a viscous oral suspension and in the form of chewable tablets, offering patients a choice in consumption method.

General Benefit of Altacid’s Dual-Salt Mechanism

The general benefit of Altacid is to provide prompt symptomatic relief from the burning and distress caused by hyperacidity. This is achieved through a dual mechanism involving immediate acid buffering from the magnesium component, which promotes rapid relief, balanced by the protective adsorption provided by the aluminium component, which aids in sustaining the effect. This balanced dual-action defines the medicine's role in the acute management of acid-related discomfort, such as the temporary flare-up of indigestion experienced after a meal.

Regulatory References

  1. Antacids - StatPearls

What side effects are possible with Altacid?

Possible Side Effects and Safety Information

The safety profile of Altacid, a non-systemic antacid containing Aluminium Hydroxide and Magnesium Hydroxide, is characterized by effects primarily localized within the Gastrointestinal System in most individuals.


Official Adverse Reaction Listings and Frequencies

Official regulatory documents classify the primary adverse reactions based on frequency and system-organ class:

  • Gastrointestinal Disorders: The opposing effects of diarrhea (linked to magnesium) and constipation (linked to aluminium) are listed as Uncommon (0.1% to 1%). Abdominal pain is also documented under the Frequency Not Known category.

  • Metabolism and Nutrition Disorders: Risks of electrolyte imbalance, including hypermagnesemia, hyperaluminemia, and hypophosphatemia, are documented, often associated with prolonged or high-dose use.

  • Immune System Disorders: The label includes listings for hypersensitivity reactions, such as pruritus or urticaria.


Safety Constraints for Specific Populations

Regulatory information highlights critical safety considerations based on patient health status and duration of use:

  • Renal Impairment: Patients with kidney disease are at increased risk for the accumulation of aluminium and magnesium. Prolonged exposure in this population is associated with severe adverse reactions, including encephalopathy and osteomalacia (bone softening), and must be avoided.

  • Long-Term Exposure: Excessive or long-term use, even with normal renal function, increases the risk of phosphate depletion due to the aluminium component binding to phosphate in the gut.

  • Drug Absorption Interference: The high-level safety profile notes that Altacid may decrease the absorption of various other orally administered medications by altering gastric pH or binding, which can affect the co-administered drug's therapeutic outcome.

Overdose and Emergency Response

An overdose of Altacid (a combination of Aluminium Hydroxide and Magnesium Hydroxide) is primarily associated with symptoms ranging from acute gastrointestinal distress to severe systemic toxicity. Documented presentations include diarrhoea, vomiting, abdominal pain, and severe constipation. Regulatory information notes that in certain high-dose or prolonged exposure scenarios, the accumulation of aluminium and magnesium ions can lead to complications such as intestinal obstruction or ileus (bowel hypomotility).

The most severe outcomes are linked to systemic magnesium accumulation, or hypermagnesemia, which can progress to life-threatening conditions. Clinical signs of severe toxicity, as described in official labeling, include a significant drop in blood pressure (hypotension), loss of deep tendon reflexes, respiratory paralysis, circulatory collapse, and cardiac arrest.

Immediate medical attention must be sought straight away if any overdose is suspected. Regulatory guidance outlines specific emergency treatment procedures, including the use of Intravenous Calcium Gluconate as an antidote for severe magnesium toxicity, alongside supportive measures like rehydration and forced diuresis to enhance ion elimination. In cases of severe toxicity or renal function deficiency, haemodialysis or peritoneal dialysis is required.

Population-specific regulatory warnings highlight that individuals with renal impairment face a significantly higher risk of systemic accumulation, hypermagnesemia, and hyperaluminemia. Additionally, elderly patients are noted to be at an increased risk of developing intestinal obstruction following large doses.

Therapeutic Uses of Altacid

Quick Facts: Altacid Therapeutic Uses

  • Addresses: Heartburn and acid indigestion.
  • Relieves: Sour stomach and related upset stomach.
  • Mechanism: Neutralizes existing stomach acid to provide temporary relief of symptoms.

Altacid is indicated for the symptomatic management of occasional heartburn, acid indigestion, and sour stomach. These uses align with its primary function of neutralizing excess stomach acid. By reducing the concentration of acid in the stomach, this medication helps to alleviate the associated discomfort, including the burning sensation in the chest or stomach.

The therapeutic benefit of Altacid is the rapid, temporary relief of symptoms of hyperacidity, which may also be associated with an upset stomach. It is considered appropriate for mild, infrequent occurrences of these symptoms. Antacids are typically used for the relief of these common digestive complaints, though long-term, continuous use of such products without clinical consultation is generally avoided to ensure that the underlying cause of frequent or persistent symptoms is determined.

Eligibility and Restrictions for Use

Population Eligibility Profile

Official regulatory documents define strict criteria for the use and non-use of Altacid (Aluminium Hydroxide/Magnesium Hydroxide). Use under standard labeled conditions is permitted for adults and adolescents 12 years of age and older.

Absolute Non-Eligibility

Altacid is contraindicated and must not be used by specific patient groups. These include individuals with severe chronic kidney disease or those undergoing dialysis, due to the critical risk of aluminum and magnesium accumulation. Use is also strictly prohibited in patients with known hypersensitivity to any ingredient, intestinal obstruction disorders, or medical conditions such as hypophosphatemia.

Conditional and Restricted Use

Official labeling mandates professional consultation for certain groups. Children under 12 years of age must consult a physician before use, as self-medication is not established in this population. Similarly, pregnant or breastfeeding individuals must “Ask a health professional before use.” Use requires caution for older adults with compromised renal function, and patients on magnesium-restricted diets must seek professional guidance prior to use.

What should I know about interactions with other medicines?

The official interaction profile for Altacid (Aluminium Hydroxide, Magnesium Hydroxide) is structured around its composition as a polyvalent cation product and its effect on gastric acidity.

Contraindicated and Restricted Combinations

Classification Interacting Product or Substance
Contraindicated Specific medicines, including Eltrombopag and Pazopanib, are formally prohibited for co-administration in regulatory documentation.
Avoid/Restricted Citrate-containing products (in foods, drinks, or medications) must be avoided in renally impaired patients due to the severe risk of enhanced aluminum absorption (hyperaluminemia).

Exposure and Timing Constraints

Altacid's effect on gastrointestinal pH and its capacity for chelation lead to reduced systemic exposure for numerous co-administered drugs.

  • Decreased Absorption: The levels of many oral drugs are reduced, including Tetracyclines, Fluoroquinolones (e.g., Ciprofloxacin, Moxifloxacin), Digoxin, Rosuvastatin, and Levothyroxine. This reduction stems from the antacid forming non-absorbable complexes or altering the environment necessary for drug uptake.
  • Administration Timing Separation: To mitigate decreased absorption, regulatory labels mandate specific timing separation. Most oral medicines should not be taken within 1 to 2 hours of the antacid. More restrictive schedules exist for specific drugs; for example, Rosuvastatin must be administered at least two hours after the antacid.

Additive and Population-Specific Risks

  • Additive Pharmacodynamic Risk: Co-administration with other magnesium-containing preparations presents an additive risk of magnesium toxicity (hypermagnesemia), which is a key regulatory concern, particularly in cases of renal impairment.
  • Population Note: Due to impaired elimination, renally impaired patients carry a heightened risk of both hypermagnesemia and hyperaluminemia when these interactions occur.

Mechanism of Action

Altacid functions as a prodrug that is activated by the acidic environment of the secretory canaliculi within gastric parietal cells. The activated compound then initiates an irreversible, covalent binding to specific cysteine residues on the extracellular domain of the H^+/ K^+- ATPase enzyme. This enzyme, commonly known as the proton pump, is solely responsible for the final step of acid secretion into the stomach lumen. The covalent interaction permanently inactivates the enzyme molecule, halting the exchange of potassium ions for hydrogen ions ( H^+). This mechanism of action directly modulates the acid secretory pathway by significantly limiting the number of functional proton pumps available in the parietal cell membrane. The reduction in the transport of hydrogen ions results in a sustained decrease in gastric acid secretion. This systemic physiological consequence modulates the biochemical environment of the stomach and esophagus by reducing acid exposure. The restoration of acid secretion depends entirely on the synthesis and insertion of new H^+/ K^+- ATPase molecules into the cell membrane.

Dosage and Administration Information

Altacid is strictly administered via the oral route and is officially available in two primary formulations: an oral suspension and chewable tablets. This medicine is intended for short-term, as-needed (PRN) use for symptomatic relief and the maximum daily dosage should not be used continuously for more than two weeks unless specifically directed by a healthcare professional.

The standard adult dosing regimen, defined for individuals aged 12 years and older, permits a single dose ranging from 10 to 20 millilitres (mL) of the suspension or one to four tablets, depending on the specific product strength. Administration frequency is generally limited to four times a day (QID) and is typically scheduled for between meals and at bedtime.

Proper administration requires specific preparation steps tied to the dosage form. The oral suspension must be shaken well immediately prior to measurement, and the dose must be accurately measured using a suitable device. Conversely, the chewable tablets must be thoroughly chewed before swallowing to ensure proper release of the active ingredients. A critical constraint on usage is the necessity to space the dose of Altacid at least two hours apart from certain other oral medications to prevent interference with their absorption. Furthermore, official labeling states that children under 12 years of age or individuals with known kidney conditions have specific administration rules that require consultation with a healthcare provider.

Recent Clinical Evidence

Research Evidence Overview for Altacid (Combination Antacids)

This overview describes the research landscape for Altacid, a combination antacid containing Aluminum Hydroxide and Magnesium Hydroxide, by summarizing its clinical evaluation from authoritative sources and peer-reviewed literature. The evidence base is primarily composed of short-term clinical trials relevant in trials assessing short-term or episodic symptom patterns.


Evidence Supporting Rapid Symptom Change for Hyperacidity

Research explored the role of Altacid in settings related to symptoms of gastric hyperacidity, including occasional heartburn and acid indigestion. The key research includes short-term Randomized Controlled Trials (RCTs) and subsequent systematic reviews.

These short-term RCTs involved adult patients and monitored outcomes related to physical discomfort. Research explored the measured time until patients reported a change in their symptoms and the duration of that change. Findings describe patterns observed in the studies where participants receiving the antacid reported a rapid symptom change that was often measured sooner than the change reported by those receiving placebo. Furthermore, studies reported how symptoms evolved in the observed populations over brief observation periods, noting that the reported change in symptoms was generally short-lived.

Evidence Quality and Limitations

Most clinical research conducted on this type of antacid is relevant in trials assessing short-term or episodic symptom patterns. The research so far suggests a consistency in trials exploring the rapid-onset characteristics of combination antacids. Comparative evidence to other types of acid-reducing agents was observed in some studies.

Long-term effects are not fully established for continuous use. The follow-up durations were limited in the primary RCTs, meaning that evidence provides limited insight into long-term outcomes, such as how symptoms evolve over many months or years. Research primarily examined short-term symptom changes and does not provide information about outcomes related to the healing of underlying mucosal damage or structural issues in the digestive tract. Data for certain groups remain insufficient, with limited controlled studies dedicated to evaluating outcomes related to physical discomfort in children or patients with complex co-existing conditions.

Key Studies & References

  1. Meta-analysis: the efficacy of over-the-counter gastro-oesophageal reflux disease therapies (Tran et al., 2007)
  2. Antacids (StatPearls - NIH, updated 2023)
  3. Aluminum Hydroxide and Magnesium Hydroxide: MedlinePlus Drug Information (NLM)

Frequently Asked Questions (FAQ)

Common questions about Altacid (FAQ)

Q: How quickly does Altacid usually start working?

Research evidence for this class of antacids describes a pattern of rapid symptom change for hyperacidity, which was observed sooner in participants receiving the antacid compared to those receiving placebo. This finding is consistent with the medicine's immediate mechanism of acid neutralization.

Q: How long can the effects of Altacid last?

Studies examining the pattern of symptom relief indicate that the observed relief was generally short-lived. The product is generally classified as a medicine intended for short-term, as-needed relief of acute symptoms, which aligns with these findings.

Q: What are the most common side effects of Altacid?

Official product information states that the effects of diarrhea (linked to magnesium) and constipation (linked to aluminum) are documented as uncommon (occurring in 0.1% to 1% of users). Abdominal pain is also listed, but its frequency is not known from the official documentation.

Q: Is Altacid considered an over-the-counter medicine in some countries?

Official documentation often positions Altacid as part of a class of medicines intended for use as over-the-counter (OTC) solutions, making it a non-prescription option for adults seeking accessible heartburn relief.

Q: Does Altacid have any food restrictions?

While general food restrictions are not typically listed, regulatory documents state that patients with impaired kidney function are cautioned to avoid citrate-containing products (in food or medicine). The combination can significantly increase aluminum absorption in this specific population, posing a critical risk.

Q: Can elderly patients use Altacid?

Altacid is permitted for adults, but the official eligibility profile describes that caution should be exercised for older adults with existing compromised renal function (kidney issues). This is due to the potential for accumulation of the active ingredients, aluminum and magnesium, in this specific group.

Q: Does Altacid contain ingredients that are common allergens?

Official product documents list the active ingredients and note the possibility of hypersensitivity reactions (allergic-type responses). Because a comprehensive list of non-active ingredients (excipients) is not detailed in the core safety summary, individuals should always review the product packaging for a complete ingredient list.

Q: Can I take Altacid if I'm already taking multiple prescriptions?

Regulatory labels require Altacid to be taken separately from many other oral medicines to prevent interference with absorption. For many co-administered drugs, specific timing separation, often 1 to 2 hours, is necessary. The product information describes these requirements.

Q: What does the term 'contraindication' mean for Altacid?

In official drug information, a contraindication describes a condition or factor that renders the use of a medication inadvisable due to a significant risk of harm. Altacid's regulatory documentation identifies conditions such as severe kidney disease and known hypersensitivity to its ingredients as contraindications.

Q: What happens if I miss taking Altacid?

Official drug information generally states that if a dose is missed, the next scheduled dose should be taken at the recommended time. Regulatory labels indicate that doubling the dose to make up for the missed one is generally not recommended.

Q: Is Altacid safe to take with common pain relievers?

Official regulatory sources indicate that antacids may interact with some common pain relievers, including aspirin and certain non-steroidal anti-inflammatory drugs (NSAIDs). The antacid may interfere with the absorption of these medicines, and in the case of aspirin, regulatory sources describe an increased risk of bleeding.

Q: Can Altacid interact with vitamins or supplements?

Antacids can interfere with the body's absorption of certain minerals (like iron and zinc) and vitamins (such as folic acid). Regulatory labels describe the necessity of administering Altacid at least 2 hours apart from these supplements to minimize the interaction risk.

Q: Are there different strengths or versions of Altacid?

Altacid's active ingredients are widely available in various formulations, including both oral suspension and chewable tablets. Regulatory data confirms that these products are offered in multiple strengths or dosages, indicating different levels of antacid content.

Q: Can taking Altacid cause changes in my sleep?

While sleep changes are not a commonly listed direct side effect, official documents note that excessive use can lead to high magnesium levels (hypermagnesemia). Systemic effects associated with hypermagnesemia include drowsiness or confusion.

Q: Does Altacid affect my ability to drive or operate machinery?

Official product information usually includes warnings about the 'Effects on the ability to drive and use machines.' If systemic side effects such as drowsiness occur (often associated with high magnesium levels from misuse), caution is generally required.

Q: Is Altacid known to cause dependence?

Altacid is categorized as a non-dependence-producing substance in official classifications. However, medical coding systems do include a diagnosis for the abuse of antacids when high dosages are used outside of labeled instructions.

Q: Is it normal to feel a bit tired when first starting Altacid?

Feeling tired (malaise or drowsiness) is not listed as a common side effect of normal use. However, these effects can occur if high magnesium levels (hypermagnesemia) develop due to excessive use or impaired kidney function.

Q: What should I know about taking Altacid with herbal teas?

Official regulatory labels include statements noting the importance of informing healthcare providers about all medicines, supplements, and herbal products being taken. This is necessary because antacids can potentially affect the absorption and effectiveness of co-administered substances.

Q: What if I take Altacid and feel no change?

Official product warnings state that if symptoms of heartburn or acid-related issues persist for more than two weeks, the official label indicates that use must be discontinued. A persistent lack of relief may be described as potentially indicating a more serious underlying condition.

Q: Is it possible for Altacid to stop working after I've used it for a while?

Medical literature on this drug class sometimes describes the development of tolerance, where the body may become less responsive over time. If the medication appears to be losing its effectiveness, professional re-evaluation of the treatment is indicated.

Q: Are there any specific medical tests required before starting Altacid?

Official guidance on labeling suggests that information regarding dosage adjustment based on laboratory investigations, such as kidney function tests, may be included for patients with renal insufficiency. This is due to the risk of accumulation of the active ingredients.

Q: Can Altacid affect blood pressure measurements?

Reports of severe overdose involving the magnesium component have been associated with hypotension (low blood pressure), especially in patients with severe kidney disease. This effect is a documented, systemic consequence of accumulation of the active ingredients.

Q: What are the general rules for stopping Altacid?

Since Altacid is typically used as an as-needed (PRN) medication, it is usually stopped when the acid symptoms resolve. For continuous use, official warnings specify that the maximum dosage is not indicated for use for more than two weeks without consulting a health professional.

Q: Is there a generic version of Altacid available?

Antacids containing this combination of aluminium and magnesium hydroxide are widely available in numerous preparations and generic equivalents under different brand names. These generic products contain the same active ingredients as Altacid.

Q: How is the safety of Altacid monitored after it has been approved?

Regulatory agencies monitor drug safety after approval through a process called pharmacovigilance. This involves reviewing spontaneous adverse experience reports, using databases for signal detection, and requiring manufacturers to submit Periodic Safety Update Reports.

How should Altacid be stored and disposed of?

How to Store and Dispose of Altacid

The storage and disposal of Altacid (Aluminium Hydroxide/Magnesium Hydroxide) must follow mandatory conditions detailed in regulatory labeling to maintain stability and ensure safety.

Official Storage Requirements

Condition Regulatory Requirement
Temperature Store at controlled room temperature, typically 20 C to 25 C (68 F to 77 F). Do not store above 25 C.
Handling Mandatory to protect from freezing. The container must be kept tightly closed.
Container Integrity Do not use the product if the tamper-evident seal is broken or missing.
Child Safety Keep out of reach of children.

Disposal Instructions

Unused or expired Altacid must be disposed of in accordance with applicable laws and regulations. The official instruction is to ask a pharmacist how to dispose of medicines no longer required. This helps prevent disposal via wastewater or household trash.

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

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