Action and mechanism

Non-absorbable antacid. Derived from aluminum and magnesium. It acts by neutralizing hydrochloric acid in the stomach, increasing gastric pH, which also reduces the formation and activity of pepsin. It also adsorbs the pepsin formed and adsorbs and neutralizes bile acids when they reflux into the stomach.

Pharmacokinetics

- Absorption: The absorption of aluminum and magnesium cations is minimal from a standard dose of antacid. Only the portion corresponding to the soluble compounds formed and the excess not precipitated in the intestine is absorbed.

- Elimination: Unabsorbed magnesium and aluminum are mostly eliminated in the feces as insoluble salts. The absorbed portion (minimal) is eliminated in the urine.


- Renal failure: In cases of renal failure, a decrease in the elimination of magnesium and aluminum may occur, with the consequent risk of hypermagnesemia and hypophosphatemia.

Indications

- Symptomatic treatment of processes that present with [GASTRIC HYPERACIDITY], such as [GASTRITIS], [DYSPEPSIA], [PEPTIC ULCER], [GASTROESOPHAGEAL REFLUX DISEASE] or [HIATAL HERNIA].

Posology

- Adults, oral:
* Chewable tablets: 2 tablets (1 g)/8 h.
* Oral suspension: 7.5 ml (1 g)/8 h.
* Envelopes: 1 envelope (1.5 g)/8 hours.
Preferably administer 0.5-1 hour after meals. In certain cases, an additional dose may be necessary before bedtime. Maximum dose: 8 g/24 h.

- Children and adolescents under 18 years of age, oral:
* Adolescents > 12 years: Same as adults.
* Children between 6-12 years: Half the adult dose.
* Children < 6 years: Safety and efficacy have not been evaluated.

- Elderly, oral: Same as adults.
Missed dose: Take as soon as possible if the missed dose has been missed. Otherwise, wait until the next dose or skip it if symptoms are bothersome. Do not double the dose at the next dose.

Rules for correct administration

- Chewable tablets: Chew or let dissolve in the mouth.

- Oral suspension: Shake the bottle vigorously before removing the dose. The suspension can be taken directly or mixed with half a glass of water.

- Oral suspension sachets: Press the sachet several times before opening. The suspension can be taken directly or mixed with half a glass of water.

Contraindications

- Hypersensitivity to any component of the medication.

- Situations in which gastrointestinal transit is difficult or impeded, such as [INTESTINAL OBSTRUCTION], [ILEUS] or [FECAL IMPACTION]. Due to the laxative effects of magnesium and the astringent effects of aluminum, the obstruction could be aggravated.

- [ABDOMINAL PAIN] of unknown origin. Treatment with a medication that can alter intestinal transit should not be started in patients with abdominal pain until the cause has been identified, as this could mask the symptoms of a more serious condition.

- Pathologies in which increased intestinal peristalsis is dangerous, such as [APPENDICITIS] or [INTESTINAL PERFORATION]. The use of drugs with a potential laxative action could aggravate the condition.

- [CHRONIC DIARRHEA]. Antacids containing magnesium may cause diarrhea.

Precautions

[KIDNEY FAILURE]. In cases of kidney failure, aluminum may accumulate in the body, leading to osteomalacia, osteodystrophy, or encephalopathy. Due to the magnesium content in almagate, hypermagnesemia may also occur.
[GASTROINTESTINAL HEMORRHAGE].
[HYPOPHOSPHATEMIA]. Due to the aluminum content of this medication, decreased phosphate absorption may occur, creating a risk of hypophosphatemia, which may cause anorexia, malaise, and muscle weakness. This condition occurs especially in patients on a low-phosphate diet, with diarrhea, malabsorption, or kidney transplant recipients. Bimonthly serum phosphate determinations are recommended, especially in patients undergoing hemodialysis.
[HYPERMAGNESEMIA]. Prolonged administration of almagate may result in magnesium accumulation.

Patient Advice

- Should not be used by patients with intestinal obstructions.

- When used as an antacid, it is recommended to take this medication after meals or when discomfort occurs.

- Shake the bottle (suspension) vigorously before use.

- Tablets and soft pills should be chewed thoroughly before swallowing. Then, drink a glass of water.

- Do not take with milk.

- If this preparation is used to relieve indigestion symptoms, it should not be taken for more than two weeks without the consent of a doctor.

- It is advisable to promptly report symptoms such as loss of appetite, weakness, or unexplained general malaise, as well as any symptoms indicating bleeding, such as black stools.

Special warnings

- Monitoring: During prolonged treatment, periodic monitoring of phosphate and calcium levels is recommended. Hypophosphatemia may increase serum calcium levels.

- It is important to monitor for possible signs of hypophosphatemia (anorexia, muscle weakness, and general malaise).

Interactions

- Ulipristal acetate-based emergency contraceptive: Increased gastric pH may reduce plasma concentrations of the contraceptive, decreasing its effectiveness. Concomitant use is not recommended.

- NSAIDs (flufenamic or mefenamic acid, indomethacin): there are studies with some antacids (algeldrate, magnesium oxide, calcium carbonate) in which a decrease in their absorption has been recorded.

- Antiulcer drugs (cimetidine, famotidine, ranitidine): there are studies in which a possible decrease in their serum levels has been recorded, due to a decrease in their absorption.

- Atorvastatin: there are studies in which a possible decrease in its absorption has been recorded.

- Beta-blockers (atenolol): There are studies in which decreased absorption has been recorded due to a decrease in the dissolution of the beta-blocker, so it is recommended to space out its administration.

- Chlorpromazine: there are some studies in which a possible decrease in its absorption has been recorded.

- Digitalis (digoxin, digitoxin): there are studies with some antacids (algeldrate, magnesium hydroxide) in which a decrease in the absorption of digitalis has been recorded, so it is recommended to space its administration 2 or 3 hours apart.

- Eltrombopag: Possible reduction in eltrombopag absorption due to the formation of insoluble chelates with polyvalent cations. Administer eltrombopag at least 4 hours before or after this medicinal product.

- Erlotinib: Possible reduction in erlotinib levels due to reduced absorption. Antacids increase gastric pH, which could decrease erlotinib solubility, absorption, and therapeutic effects. It is recommended to administer at least 4 hours before or 2 hours after the daily dose of the antineoplastic agent.

- Fosinopril: There is a study that describes a possible reduction in its absorption.

- Gabapentin: Some decreases in gabapentin levels have been observed when administered concomitantly with or within two hours of taking other antacids, due to an increase in pH. It is recommended that gabapentin be administered two hours before an antacid.

- Ketoconazole: There are studies in which a possible decrease in the absorption of ketoconazole has been recorded, due to the increase in pH, which causes less solubilization of the drug.

- Lansoprazole: There are studies in which a possible decrease in the absorption of lansoprazole has been recorded.

- Penicillamine: There are studies in which a decrease in penicillamine absorption has been recorded, due to the possible formation of poorly soluble complexes.

- Prednisone: there are studies in which a possible decrease in its absorption has been recorded.

- Iron chelators (deferasirox, deferiprone, deferoxamine): possible reduction of the antacid effect due to the formation of insoluble complexes with aluminium.

- Quinidine: there are studies in which a possible increase in its toxicity has been recorded due to a decrease in its excretion due to alkalinization of urine.

- Quinolones (ciprofloxacin): there are studies in which a decrease in their absorption has been recorded due to the formation of insoluble, non-absorbable complexes at the intestinal level, so it is recommended to separate their administration by 2 or 3 hours.

- Iron salts (iron sulfate): there are studies in which a decrease in absorption has been recorded due to the formation of poorly soluble complexes, so it is recommended to space administration by 2 or 3 hours.

- Salicylates (acetylsalicylic acid): Studies have shown decreased salicylate levels due to increased excretion caused by alkalinization of urine, especially at high doses of salicylate. The administration of aluminum-derived antacids alone seems advisable, given their likely reduced effect.

- Tetracyclines (chlortetracycline, demeclocycline, doxycycline): there are studies with some antacids (algeldrate, aluminum hydroxide) in which the possible formation of non-absorbable complexes at the gastrointestinal level has been recorded, thus decreasing their absorption, so it is recommended to space administration by 2 or 3 hours.

Pregnancy

FDA Category B. Some preliminary studies with aluminum, magnesium, and calcium hydroxides had observed a possible two-fold increase in the incidence of various types of birth defects in children; however, subsequent studies have not confirmed these observations. However, isolated cases of hypercalcemia and hyper- and hypomagnesemia have been reported in association with chronic antacid use during pregnancy. Likewise, isolated cases of increased tendon reflexes in fetuses and newborns have been reported. Excessive use and prolonged use are recommended.

Lactation

With the use of antacids in general, small amounts of magnesium and aluminum may be excreted in breast milk, although these amounts do not appear to be sufficient to cause adverse effects in the newborn. This is an accepted use, but chronic and/or excessive use is recommended to be avoided.

Children

Uncontrolled use of antacids is not recommended in children under 6 years of age, as they may mask serious symptoms (appendicitis, etc.). Furthermore, magnesium antacids carry a risk of hypermagnesemia in young children, especially if they show symptoms of dehydration or suffer from kidney failure.

Seniors

The prolonged use of aluminum antacids in the elderly can lead to systemic absorption of aluminum, producing organic accumulation. This could worsen the osteoporosis present in almost all elderly patients due to phosphorus and calcium depletion and the inhibition of digestive fluoride absorption. A possible accumulation of magnesium should also be taken into account, which could cause hypermagnesemia and diarrhea. Chronic and/or excessive use is not recommended in the elderly, especially in patients with Alzheimer's disease, as a potential etiological role of aluminum in this disease has been suggested.

Adverse reactions

Almagate's adverse effects are generally mild and transient. The most common adverse reactions are:
-Exceptionally (<<1%): [CONSTIPATION] or [DIARRHEA] when high doses are used. In prolonged treatments with high doses or in patients on low phosphate diets, it may induce [HYPOPHOSPHATEMIA] and cause [OSTEOMALACIA].

Overdose

- Symptoms: Unknown. Intestinal absorption is minimal, so overdose is very rare. In patients with severe renal impairment, there may be increased toxicity from aluminum and/or magnesium, manifesting in the brain, bones, and parathyroid glands.

Conservation

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- It is advisable to keep them in a cool, dry place, away from light and heat sources. Preferably at a temperature no higher than 30°C.