Magnesium hydroxide Ibuprofen

NSAIDs ANTACIDS 1. Magnesium hydroxide T absorption of ibuprofen, flurbiprofen, mefenamic acid and tolfenamic acid 2. Aluminium-containing antacids l absorption of these NSAIDs Uncertain These effects are 1 by taking these drugs with food... 

Neuvonen PJ. The effect of magnesium hydroxide on the oral absorption of ibuprofen, keto-profen and diclofenac. BrJ Clin Pharmacol ( 99 ) 31,263-6. 

Information is very limited but it would appear that if rapid analgesia is needed with either mefenamic acid or tolfenamic acid, magnesium hydroxide can be given concurrently but aluminium hydroxide should be avoided. However, note that this applies to the fasted state, whereas NSAIDs are usually taken with or after food. Also note that magnesium hydroxide increased the endoscopically-detected gastric toxicity of ibuprofen in one study, see NSAIDs Ibuprofen and related drugs -i- Antacids , below. Aluminium hydroxide markedly reduces the speed of absorption. Sodium bicarbonate does not interact. Consider also NSAIDs Miscellaneous + Antacids , p.l42. 

Magnesium hydroxide increased the initial absorption of ibuprofen and flurbiprofen, but had no effect on ketoprofen. Unexpectedly, a pharmacodynamic study showed increased gastric erosions when ibuprofen was formulated with magnesium hydroxide. 

A small reduction in ketoprofen absorption occurred with aluminium-magnesium hydroxide, but dexketoprofen, ibuprofen and flurbiprofen were not affected, and naproxen showed a slight increase in rate and extent of absorption. Aluminium phosphate had no effect on ketoprofen absorption. 

Magnesium hydroxide appears to improve the rate of absorption of some acidic NSAIDs (which become more soluble as the pH rises) such as ibuprofen and flurbiprofen. Why this increased the gastric toxicity of ibuprofen in the one pharmacodynamic study is unclear. Sodium bicarbonate appears to have a similar effect on rate of absorption. Aluminium antacids do not produce soluble salts with these NSAIDs, and may therefore reduce the rate/extent of absorption. 

The absorption of raloxifene is reduced by colestyramine, and their concurrent use is not recommended. No clinically relevant changes in raloxifene pharmacokinetics occur with alumini-um/magnesium hydroxide, amoxicillin, ampicillin or calcium carbonate. Raloxifene does not alter digoxin or methylprednisolone levels. Oral antibacterials, antihistamines, aspirin, benzodiazepines, H2-receptor antagonists, ibuprofen or paracetamol (acetaminophen) were used in clinical studies without any obvious effect on raloxifene levels. Smoking does not appear to alter the efficacy of raloxifene. 

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