What is the recommended dose of Mylanta (aluminum hydroxide/magnesium hydroxide) for adults?

Mylanta Dosing for Adults

For adults using Mylanta (aluminum hydroxide/magnesium hydroxide) as an antacid, the recommended dose is 5 to 15 mL (1 to 3 teaspoonfuls) taken as needed, not exceeding the maximum daily dose in a 24-hour period. 1

Standard Antacid Dosing

• Adults and children 12 years and older: 5 to 15 mL (1 to 3 teaspoonfuls) per dose 1
• Shake well before use and can be taken with water 1
• Do not exceed the maximum recommended daily dose in a 24-hour period 1

Alternative Laxative Dosing (When Used for Constipation)

If using the magnesium hydroxide component specifically for laxative effect:

• Adults and children 12 years and older: 30 mL (2 tablespoons) to 60 mL (4 tablespoons) once daily 1
• Preferably taken at bedtime, in divided doses, or as directed by a physician 1
• Maximum daily dose: 60 mL in a 24-hour period 1
• Drink a full glass (8 oz) of liquid with each dose 1

Clinical Context from Guidelines

When magnesium hydroxide is used for opioid-induced constipation (a common clinical scenario), the National Comprehensive Cancer Network recommends:

• 30-60 mL daily as an add-on agent when first-line laxatives are insufficient 2
• This dosing is used after ruling out bowel obstruction and checking for impaction 2

Important Drug Interactions

• Fluoroquinolones: Mylanta significantly reduces absorption of moxifloxacin and other fluoroquinolones 3
• Administer Mylanta at least 4 hours after fluoroquinolone administration 3

Special Population Considerations

• Elderly patients: May require dose reduction due to increased risk of side effects with aluminum-containing antacids 3
• Renal impairment: Use caution, as aluminum can accumulate in the body with chronic use 3, 4
• Long-term use without medical supervision may lead to phosphate depletion 4