Reduced effect of L-dopa when in concomitant w/ vit B
6. Decreased efficacy of vit B
6 w/ pyridoxine antagonists eg, INH, cycloserine, penicillamine, hydralazine. Reduced blood level of vit B
1 w/ loop diuretics eg, furosemide. Vit B
12 deficiency w/ long-term use of acid lowering agents. Potentiated effect of oral anticoagulant (eg, warfarin). Risk of paracetamol toxicity w/ other potentially hepatotoxic drugs or drugs that induce liver microsomal enzymes (eg, antiepileptics). Decreased effectiveness of lamotrigine. Hepatotoxicity w/ alcohol.