Ethambutol Aluminium hydroxide

In 13 patients with tuberculosis, aluminium hydroxide significantly lowered serum ethambutol concentrations during the first 4 hours after a dose in healthy volunteers, both aluminium hydroxide and glycopyrrhonium, alone or in combination, reduced ethambutol absorption (26). 

Mattila MJ, Linnoila M, Seppala T, Koskinen R. Effect of aluminium hydroxide and glycopyrrhonium on the absorption of ethambutol and alcohol in man. Br J Chn Pharmacol 1978 5(2) 161-6. 

Aluminium hydroxide and aluminium/magnesium hydroxide can cause a small but probably clinically unimportant reduction in the absorption of ethambutol in some patients. 

A study in 13 patients with tuberculosis, given a single 50-mg/kg dose of ethambutol, found that when they were also given three 1.5-g doses of aluminium hydroxide gel (at the same time and 15 and 30 minutes later) their peak serum ethamhutol levels were delayed and reduced. The average uri nary excretion of ethamhutol over a 10-hour period was reduced hy about 15%, but there were marked variations between individual patients. Some showed no interaction, and others showed increased absorption. No interaction was seen in 6 healthy subjects similarly treated. A further study in 14 healthy subjects found that 30 mL of an aluminium/magnesi-um hydroxide antacid decreased the AUC and maximum serum levels of a 25-mg/kg dose of ethambutol by 10% and 29%, respectively. ... 

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