Action and mechanism

Non-absorbable antacid. Aluminum and magnesium derivative. It works by neutralizing hydrochloric acid in the stomach, increasing gastric pH, which also reduces the formation and activity of pepsin. In addition, it adsorbs pepsin that has 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 whose excess has 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 insufficiency: In cases of renal insufficiency, a decrease in the elimination of magnesium and aluminum could occur, with the consequent risk of hypermagnesemia and hypophosphatemia.

Instructions

- Symptomatic treatment of processes that involve [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.
Administer preferably 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 it hasn't been long. Otherwise, wait until your next scheduled dose or take it earlier if symptoms are bothersome. Do not double the dose at the next scheduled dose.

Guidelines for proper administration

- Chewable tablets: Chew or allow to dissolve in the mouth.

- Oral suspension: Shake the bottle vigorously before withdrawing the dose. The suspension can be ingested directly or in half a glass of water.

- Oral suspension sachets: Press the sachet several times before opening. The suspension can be ingested directly or in 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 drug that may alter intestinal transit should not be initiated in patients suffering from abdominal pain until the cause has been identified, as it could mask the symptoms of a more serious condition.

- Conditions in which increasing intestinal peristalsis is dangerous, such as appendicitis or intestinal perforation. The use of drugs with a potential laxative effect could worsen the condition.

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

Precautions

[RENAL INSUFFICIENCY]. In cases of renal insufficiency, aluminum may accumulate in the body, potentially leading to osteomalacia, osteodystrophy, or encephalopathy. Due to the magnesium content of almagate, hypermagnesemia may also occur.
[GASTROINTESTINAL HEMORRHAGE].
[HYPOPHOSPHATEMIA]. Due to the aluminum content of this medication, decreased phosphate absorption may occur, with a risk of hypophosphatemia, which presents with anorexia, malaise, and muscle weakness, appearing primarily in patients with a low-phosphate diet, diarrhea, malabsorption, or kidney transplant. Bimonthly monitoring of serum phosphate levels is recommended, especially in patients undergoing hemodialysis.
[HYPERMAGNESEMIA]. In case of prolonged administration of almagate, an accumulation of magnesium may occur.

Advice to the patient

- It 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 (the suspension) vigorously before use.

- Tablets and softgels 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 a doctor's consent.

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

Special warnings

- Monitoring: During prolonged treatment, periodic monitoring of phosphate and calcium levels is advised. Hypophosphatemia can 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): studies have shown decreased absorption due to reduced dissolution of the beta-blocker, so it is recommended to space out its administration.

- Chlorpromazine: there are some studies that have recorded a possible decrease in its absorption.

- 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 h.

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

- Erlotinib: possible reduction in erlotinib levels due to decreased absorption. Antacids increase gastric pH, which could decrease erlotinib solubility, absorption, and therapeutic effects. It is recommended to administer antacids 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: A decrease in gabapentin levels has been observed when administered concurrently with or within two hours of taking other antacids, due to an increase in pH. It is recommended to administer gabapentin 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 the absorption of penicillamine 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 aluminum.

- Quinidine: there are studies in which a possible potentiation of its toxicity has been recorded due to decreased excretion caused by alkalinization of the urine.

- Quinolones (ciprofloxacin): studies have shown a decrease in their absorption 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 (ferrous sulfate): studies have shown a decrease in absorption due to the formation of poorly soluble complexes, so it is recommended to space out administration by 2 or 3 hours.

- Salicylates (acetylsalicylic acid): Studies have shown a decrease in salicylate levels due to increased excretion resulting from urine alkalinization, especially at high salicylate doses. It seems advisable to administer only aluminum-based antacids, given their likely reduced effect.

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

Pregnancy

FDA Pregnancy Category B. Some preliminary studies with aluminum, magnesium, and calcium hydroxides observed a possible doubling of the incidence of various types of congenital anomalies in children; however, subsequent studies have not confirmed these observations. Nevertheless, 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 described. Excessive use and prolonged use should be avoided.

Lactation

With the use of antacids in general, small amounts of magnesium and aluminum may be excreted in breast milk, which do not appear to be sufficient to cause adverse effects in the newborn. Use is acceptable, although chronic and/or excessive use should be avoided.

Children

The uncontrolled use of antacids in children under 6 years of age is not recommended, as they could mask serious symptoms (appendicitis, etc.). Furthermore, magnesium-based antacids carry a risk of hypermagnesemia in young children, especially if they are dehydrated or have kidney failure.

Seniors

Prolonged use of aluminum-containing antacids in the elderly can lead to systemic absorption of aluminum, resulting in its accumulation in the body. This could exacerbate osteoporosis, which is present in almost all elderly individuals due to phosphorus and calcium depletion, as well as the inhibition of fluoride absorption in the digestive system. A possible accumulation of magnesium, which could cause hypermagnesemia and diarrhea, should also be considered. 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

The adverse effects of almagate are generally mild and transient. The most characteristic 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 aluminum and/or magnesium toxicity, 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.