Usage
Magaldrate is an antacid used to treat symptoms caused by excess stomach acid, such as heartburn, upset stomach, sour stomach, and acid indigestion. It is also used to manage symptoms related to gastroesophageal reflux disease (GERD), peptic ulcers, gastritis, peptic esophagitis, and hiatal hernia. Additionally, magaldrate may be used to treat hyperphosphatemia (high phosphate levels in the blood) and magnesium deficiency. Its pharmacological classification is antacid.
Magaldrate works by neutralizing stomach acid, thereby increasing gastric pH. This chemical reaction reduces the irritant effect of the acid on the stomach lining and inactivates pepsin, a digestive enzyme that can contribute to mucosal damage. Additionally, magaldrate can enhance the integrity of the mucosal barrier and improve the tone of the lower esophageal sphincter.
Alternate Names
Magaldrate is also known as aluminum magnesium hydroxide. Some brand names for magaldrate or magaldrate-containing products include Riopan and Lowsium. Regional variations may exist. Some formulations combine magaldrate with simethicone, an anti-flatulent agent, and are marketed under brand names like Riopan Plus and Ron Acid Plus.
How It Works
Pharmacodynamics: Magaldrate neutralizes gastric acid, increasing gastric pH and inactivating pepsin. This reduces the irritant effect of acid on the stomach lining. The drug may also enhance the mucosal barrier and improve gastroesophageal sphincter tone.
Pharmacokinetics:
- Absorption: Aluminum and magnesium components can be absorbed systemically, although absorption is generally low and unrelated to the mechanism of action. The risk of magnesium absorption is a concern in patients with renal impairment. Some aluminum and magnesium may appear in breast milk.
- Distribution: Primarily local in the gastrointestinal tract.
- Metabolism: None.
- Elimination: Excreted primarily in feces.
Mode of Action: Magaldrate is a complex of aluminum and magnesium hydroxides. Upon contact with gastric acid (HCl), it undergoes a chemical reaction, producing aluminum chloride, magnesium chloride, and water, effectively neutralizing the acid and raising gastric pH.
Receptor Binding, Enzyme Inhibition, or Neurotransmitter Modulation: Magaldrate does not exhibit any significant receptor binding, enzyme inhibition, or neurotransmitter modulation properties. Its action is primarily based on chemical neutralization of gastric acid.
Elimination Pathways: Magaldrate and its byproducts are mainly eliminated through fecal excretion. Some aluminum and magnesium may be absorbed systemically and excreted renally.
Dosage
Standard Dosage
Children: Safety and efficacy have not been fully established in pediatric patients. Dosing should be determined by a physician and adjusted based on the child’s weight and age.
Special Cases:
- Elderly Patients: Dose adjustments may be needed based on renal function.
- Patients with Renal Impairment: Use cautiously in patients with renal impairment. Reduce dose to avoid aluminum and magnesium accumulation and toxicity.
- Patients with Hepatic Dysfunction: No specific dose adjustments are typically needed. However, use with caution in patients with severe hepatic impairment, especially if there is a risk of concomitant renal failure.
- Patients with Comorbid Conditions: Caution is advised in patients with heart failure, hypertension, or those on a sodium-restricted diet, as some formulations may contain sodium.
Clinical Use Cases
Magaldrate is not typically indicated for use in clinical settings like intubation, surgical procedures, mechanical ventilation, ICU, or emergency situations. It is primarily used for the management of dyspepsia and related conditions in a non-acute setting.
Dosage Adjustments
Dosage adjustments are primarily based on renal function. Monitoring of serum magnesium and aluminum levels may be necessary in patients with renal impairment.
Side Effects
Common Side Effects:
Constipation, diarrhea, nausea, and chalky taste.
Rare but Serious Side Effects:
Aluminum intoxication (in patients with renal impairment), hypermagnesemia (high magnesium levels), hypophosphatemia (low phosphate levels), osteomalacia (bone softening), and allergic reactions. Black, tarry stools, coffee-ground vomitus, or dark urine may indicate gastrointestinal bleeding and require immediate medical attention.
Long-Term Effects:
Osteomalacia and other bone-related complications can occur with prolonged use, especially in patients with renal impairment.
Adverse Drug Reactions (ADR):
Severe allergic reactions, including anaphylaxis, although rare, require immediate medical attention.
Contraindications
Magaldrate is contraindicated in patients with severe renal disease and hypersensitivity to magaldrate or its components. Use with caution in patients with mild to moderate renal impairment. It should be used carefully by those on a magnesium-restricted diet and with caution in those taking citrate salts found in calcium supplements, antacids, and laxatives.
Drug Interactions
Magaldrate can interfere with the absorption of several medications, including tetracyclines, quinolones, iron supplements, digoxin, and some oral antidiabetic medications. It can also interact with anticoagulants, antimuscarinics, chlordiazepoxide, diazepam, isoniazid, phenothiazines (especially chlorpromazine), phosphates, and vitamin A. Separate administration times by 1–2 hours to minimize interactions. Concurrent use with sodium polystyrene sulfonate can lead to serious complications.
Pregnancy and Breastfeeding
Magaldrate is classified as Pregnancy Risk Category C, which signifies that animal studies have shown adverse effects on the fetus, but there are no adequate and well-controlled studies in humans. Use during pregnancy only if the potential benefits outweigh the potential risks. Small amounts of aluminum and magnesium can be excreted in breast milk. Consult with a physician before using magaldrate while breastfeeding.
Drug Profile Summary
- Mechanism of Action: Neutralizes gastric acid, increasing gastric pH, inactivating pepsin, and potentially enhancing mucosal barrier integrity.
- Side Effects: Constipation, diarrhea, nausea, chalky taste. Rarely, aluminum intoxication or hypermagnesemia.
- Contraindications: Severe renal disease, hypersensitivity to magaldrate.
- Drug Interactions: Interferes with the absorption of numerous medications; separate administration times are necessary.
- Pregnancy & Breastfeeding: Pregnancy Category C; use with caution. Small amounts may be present in breast milk.
- Dosage: Adults: 5–10 mL (or 1-2 tablets) between meals and at bedtime. Pediatric dosing should be determined by a physician.
- Monitoring Parameters: Renal function, serum magnesium and aluminum levels (in patients with renal impairment).
Popular Combinations
Magaldrate is sometimes combined with simethicone for the relief of gas and bloating.
Precautions
Screen patients for renal impairment, history of drug allergies, and other gastrointestinal conditions before initiating treatment. Exercise caution in patients with any history of appendicitis, stomach pain, nausea, vomiting, diarrhea, blockage of the bowel, rectal bleeding of unknown cause, kidney problems, or have undergone recent bowel surgery, on a low-magnesium diet, who are taking other medications, any allergy, during pregnancy and breastfeeding.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Magaldrate?
A: Adults: 5-10 mL (1-2 teaspoonfuls or 540-1080 mg) between meals and at bedtime, not to exceed 80 mL (16 teaspoonfuls) in a 24-hour period. Pediatric dosing should be individualized based on the child’s weight, age, and medical condition.
Q2: How does Magaldrate work?
A: Magaldrate neutralizes stomach acid, increasing gastric pH and inactivating pepsin, thereby reducing the irritant effect of acid on the stomach lining.
Q3: What are the common side effects of Magaldrate?
A: Common side effects include constipation, diarrhea, nausea, and a chalky taste.
Q4: Is Magaldrate safe during pregnancy?
A: Magaldrate is Pregnancy Category C. It should only be used if the benefits outweigh the potential risks.
Q5: Can I take other medications with Magaldrate?
A: Magaldrate can interact with many medications, including tetracyclines, quinolones, iron supplements, digoxin, and some diabetes medications. Separate administration times by 1–2 hours. Consult a physician or pharmacist about potential drug interactions.
Q6: What are the contraindications for Magaldrate?
A: Severe renal disease, hypersensitivity to magaldrate or its components. Use with caution in patients with mild to moderate renal impairment.
Q7: What should I do if I miss a dose of Magaldrate?
A: If you miss a dose, take it as soon as you remember. If it is close to the time for your next dose, skip the missed dose and return to your regular dosing schedule. Do not double the dose.
Q8: What precautions should be taken when using Magaldrate?
A: Patients with kidney disease should use with caution. Monitor serum magnesium and aluminum levels, especially in patients with renal impairment. Consult with a physician about using magaldrate while breastfeeding.
Q9: What is the difference between Magaldrate and other antacids?
A: Magaldrate is a combination of aluminum and magnesium hydroxide, providing a balanced antacid effect with a relatively lower risk of causing constipation (associated with aluminum hydroxide) or diarrhea (associated with magnesium hydroxide).
Q10: How long can I take Magaldrate?
A: For occasional heartburn or indigestion, short-term use is generally sufficient. For chronic conditions, consult with a physician to determine the appropriate duration of treatment. Do not take magaldrate continuously for more than 14 days without medical supervision.
