Avoid concomitant use w/ dabigatran etexilate, methacholine, topotecan. May increase level/effect of α/β agonist (direct-acting), α1
-agonist, amifostine, antihypertensive, antipsychotic (phenothiazine), cardiac glycoside, colchicine, cyclosporin, dabigatran etexilate, digoxin, hypotensive agent, insulin, lidocaine (systemic & topical), methacholine, midodrine, P-glycoprotein substrate, rituximab, rivaroxaban, sulfonylurea, topotecan. Level/effect may be increased by acetylcholinesterase inhibitor, aminoquinoline (antimalarial), amiodarone, anilidopiperidine opioid, phenothiazine, non-dihydropyridine Ca channel blocker, cimetidine, CYP2C9 or CYP2D6 inhibitor (moderate/strong), darunavir, diazoxide, dipyridamole, disopyramide, dronedarone, herb (w/ hypotensive properties), MAOI, pentoxifylline, P-glycoprotein inhibitor, phosphodiesterase 5 inhibitor, propafenone, propoxyphene, prostacyclin analogue, quinidine, reserpine, SSRI. May decrease level/effect of β2
-agonist, theophylline derivative. Level/effect may be decreased by barbiturate, herb (w/ hypertensive properties), methylphenidate, NSAIDs, peginterferon α2b, P-glycoprotein inducer, rifampicin derivative, yohimbine.