Formation of non-absorbable complexes w/ alendronate, ciprofloxacin, doxycycline. Reduced GI absorption w/ antacids. Enhanced GI absorption w/ ascorbic acid. May increase serum Fe levels w/ chloramphenicol. May reduce GI absorption w/ cimetidine. Decreased serum levels of levodopa. May result in decreased efficacy of methyldopa. Decreased GI absorption of quinolones & penicillamine. Decreased absorption of both tetracycline & Fe salts. Eggs & milk inhibit Fe absorption. Administration of Ca & Fe supplementation reduces ferrous sulfate absorption by 1
/3. Folic acid:
Decreased effects of anticonvulsants eg, amobarbital, aprobarbital, butabarbital, dihydroquinidine barbiturate, heptabarbital, hexobarbital, methohexital, methylphenobarbital, pentobarbital, primidone, quinidine barbiturate. May decrease levels of phenytoin.