buprenorphine + dextromethorphan

use alternative or monitor serotonin syndrome sx, especially during initiation/titration: combo may incr. risk of serotonin syndrome (additive effects)

buprenorphine + promethazine

use alternative or monitor respiratory rate, BP; decr. buprenorphine by at least 25-50%, consider decr. promethazine dose, use lowest effective doses and shortest duration of concomitant tx: combo may incr. risk of profound CNS and respiratory depression, psychomotor impairment, seizures, severe hypotension (including orthostasis, syncope), severe constipation, paralytic ileus, urinary retention (additive effects)

promethazine + tetrabenazine

use alternative or monitor ECG, respiratory rate; decr. dose of one or both drugs: combo may incr. risk of QT prolongation, cardiac arrhythmias, CNS and respiratory depression, psychomotor impairment, extrapyramidal symptoms (additive effects)

buprenorphine + tetrabenazine

monitor respiratory rate, ECG; decr. dose of one or both drugs, use lowest effective doses and shortest duration of concomitant tx: combo may incr. risk of profound CNS and respiratory depression, psychomotor impairment, QT prolongation, cardiac arrhythmias (additive effects)

dasatinib + tetrabenazine

monitor ECG, electrolytes: combo may incr. risk of QT prolongation, cardiac arrhythmias (additive effects)