Barbiturates may decrease the effectiveness of oral contraceptives, certain antibiotics, quinidine, theophylline, corticosteroids, anticoagulants, and beta blockers.
<Barbiturates, effect, contraceptives>, <Barbiturates, effect, antibiotics>, <Barbiturates, effect, quinidine>, <Barbiturates, effect, theophylline>, <Barbiturates, effect, corticosteroids>, <Barbiturates, effect, anticoagulants>, <Barbiturates, effect, beta blockers>