Naproxen Magnesium oxide

Figure 10.3 Mean plasma concentrations ( [ g cm of naproxen in 14 male volunteers with and without intake of sodium bicarbonate, magnesium oxide or aluminium hydroxide.

Naproxen is absorbed fully when administered orally. Food delays the rate but not the extent of absorption. Peak concentrations in plasma occur within 2 to 4 hours and are somewhat more rapid after the administration of naproxen sodium. Absorption is accelerated by the concurrent administration of sodium bicarbonate but delayed by magnesium oxide or aluminum hydroxide. Naproxen also is absorbed rectally, but more slowly than after oral administration. The half-life of naproxen in plasma is variable. It is about 14 hours in the young, but it may increase about twofold in the elderly because of age-related decline in renal function. 

Magnesium Hydroxide Magnesium Oxide Magnesium Silicate Hydroxide Magnesium Sulfate Menthol Methyl Alcohol Methyl-t-butyl Ether Monosodium Glutamate N,N-Diethyl-3-Methyl-benzamide Naproxen Niacin Nitric Acid Nitric Oxide Nitrogen Dioxide Nitroglycerin Nitrous Oxide Nylon 6 and Nylon 66 Oxalic Acid Pectin Penicillin Perchlorates Petroleum Phenol... 

With respect to concomitant antacid administration past studies have shown that sodium bicarbonate enhances the rate of naproxen absorption, magnesium carbonate caused a slight reduction, and a mixture of magnesium oxide and aluminium hydroxide gave a clear reduction in the rate of naproxen absorption (17). 

Sodium bicarbonate increased the rate of naproxen absorption, and aluminium hydroxide and magnesium oxide decreased it. Dimeticone did not affect ketoprofen bioavailability. 

Sodium bicarbonate 700 mg or 1.4 g increased the rate of absorption of a single 300-mg dose of naproxen in 14 healthy fasted subjects, whereas magnesium oxide or aluminium hydroxide 700 mg had the opposite effect, and reduced the rate of absorption. Magnesium carbonate had little effect. On the other hand when 15 or 60 mL of aluminium/magnesium hydroxide (Maalox) was given, the rate and extent of absorption of naproxen were slightly increased. ... 

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