Concomitant use w/ drugs known to prolong QT interval eg, class IA or III antiarrhythmics, TCAs, macrolides, antipsychotics. Reduced absorption w/ multivalent cation-containing drugs & mineral supplements (eg, Ca, Mg, Al, Fe), polymeric phosphate binders (eg, sevelamer or lanthanum carbonate), sucralfate or antacids, & highly buffered drugs (eg, didanosine tab) containing Mg, Al or Ca. Absorption may be reduced w/ dairy products or mineral-fortified drinks alone eg, milk, yoghurt, Ca-fortified orange juice. Increased serum conc w/ probenecid. Accelerated absorption w/ metoclopramide. Slight reduction in C
max & AUC w/ omeprazole. Increased serum conc of tizanidine; theophylline; clozapine. May increase plasma levels of MTX & risk of MTX-associated toxic reactions. Raised serum conc of other xanthine derivatives eg, caffeine or pentoxifylline (oxpentiphylline). May result in increased or reduced serum levels of phenytoin. Transient rise in serum creatinine conc of cyclosporin. May augment anticoagulant effects of vit K antagonist. May result in increase of AUC & C
max of duloxetine. Increased C
max & AUC of ropinirole; sildenafil. Reduced clearance of lidocaine IV. Increased exposure of agomelatine. May increase blood levels of zolpidem.