UK Clinical Pharmacy Association

Simeticone with aluminium hydroxide and magnesium hydroxide

Brands of simeticone with aluminium hydroxide and magnesium hydroxide

Maalox Plus®

Issues for surgery

Loss of symptomatic relief from dyspepsia and gastro-oesophageal reflux disease (GORD) if omitted.

Advice in the perioperative period

Elective and emergency surgery 

Omit dose(s) whilst fasting (including combination product).

Combination product:

  • Kolanticon (dicycloverine + aluminium hydroxide, magnesium hydroxide and simethicone) – see also Antispasmodics (antimuscarinics) drug records.

Perioperative considerations

For patients with increased risk factors for aspiration (e.g. pregnancy, obesity, non-fasted state in emergency surgery) consider administration of acid-suppressing medication (oral or intravenous) pre-operatively.

Post-operative advice

Restart post-operatively, when required.

Aluminium containing antacids should be used with caution in patients with renal impairment, particularly if also prescribed effervescent medications e.g. soluble paracetamol (see Further information).

For patients on enteral feeds – see Interactions with other common medicines used in the perioperative period.

Patients undergoing anti-reflux surgery or total gastrectomy

Review continued need for antacids following surgery.

Interactions with common anaesthetic agents


Interactions with other common medicines used in the perioperative period

Administration of antacids containing aluminium and magnesium might damage enteric coatings designed to prevent dissolution in the stomach and can impair absorption of other medications. If administering medication where a reduction in bioavailability could have a clinically significant effect on safety or efficacy (e.g. antimicrobials), administration of the medication should be separated from the antacid, to allow for appropriate absorption.


Common antimicrobials used in the perioperative period where a significant reduction in bioavailability has been shown or where there is a theoretical interaction include:

  • Quinolone antimicrobials (ciprofloxacin, levofloxacin)
  • Tetracycline antimicrobials (doxycycline)

Consult product literature for recommendations on separating doses to ensure absorption.


Administration of oral iron preparations should be separated from antacids to allow for appropriate absorption, consult product literature for recommended interval.


Large doses of some antacids can reduce the bioavailability of corticosteroids; however, it appears small doses do not interact. Given the uncertainty consider separating administration of oral corticosteroids and antacids by 2-3 hours.

Enteral feeds

Aluminium containing antacids have formed bezoars (relatively insoluble complexes) with the protein in enteral feeds which has resulted in blockage of enteral tubes.

Further information

Risk of aluminium toxicity

Absorption of aluminium from aluminium salts is enhanced by citrates which are found in many effervescent preparations e.g. soluble analgesia. Caution is needed in individuals with renal impairment as aluminium toxicity could occur.


Baxter K, Preston CL (eds), Stockley’s Drug Interactions (online) London: Pharmaceutical Press. [Accessed on 18th September 2021]

Joint Formulary Committee. British National Formulary (online) London: BMJ Group and Pharmaceutical Press. [Accessed on 18th September 2021]

Summary of Product Characteristics – Maalox Plus® (Simeticone with aluminium hydroxide and magnesium hydroxide) Suspension. SANOFI. Accessed via 18/09/2021 [date of revision of the text January 2021]