acetaminophen + acetaminophen

limit acetaminophen from all sources to standard max acetaminophen doses: combo may incr. acetaminophen levels, risk of hepatotoxicity, other adverse effects (additive effects, duplicate therapy)

butalbital + dihydrocodeine

use alternative or monitor respiratory rate, withdrawal sx; consider decr. dose of one or both drugs, use lowest effective doses and shortest duration of concomitant tx: combo may decr. dihydrocodeine and active metabolite dihydromorphine levels, efficacy; may incr. risk of profound CNS and respiratory depression, psychomotor impairment (hepatic metabolism induced, may decr. production of active metabolite dihydromorphine; additive effects)