eTable. Selected drug interactions of relevance to the pediatric setting (modified from [11]).

Drug 1	Drug 2	Interaction
ACE inhibitor	Spironolactone	Increase in serum potassium concentration owing to additive effects on renal reabsorption
ACE inhibitor	Allopurinol	Increased risk of life-threatening skin reactions
Azathioprine/mercaptopurine	Allopurinol	Inhibition of xanthine oxidase by allopurinol inhibits the breakdown of azathioprine, dosage reduction required
Beta blocker	Insulin	Risk of hypoglycemia, as warning signs of hypoglycemia are lessened
Beta blocker	Beta mimetics, e.g. salbutamol	Mutual inhibition of effect
Carbamazepine, oxcarbazepine	Antiepileptic drugs e.g. lamotrigine, valproate	Increased breakdown of antiepileptic drugs owing to enzyme induction
Ciclosporin	Rifampicin	Drop in ciclosporin concentration owing to enzyme induction (CYP3A4)
Ciclosporin	Clarithromycin	Rise in ciclosporin concentration owing to enzyme induction (CYP3A4)
Lamotrigine	Oral contraceptives	Induction of lamotrigine breakdown
Ciprofloxacine/ofloxacine	Theophylline	Rise in plasma concentration of theophylline owing to enzyme induction (CYP1A2)
Meropenem	Valproate	Drop in plasma concentration of valproate
Phenobarbital	Antiepileptic drugs e.g. carbamazepine, lamotrigine	Increased breakdown of antiepileptic drugs owing to enzyme induction
Proton pump inhibitors e.g. omeprazole	Propranolol	Reduced resorption of propranolol
Combination of several QT interval prolonging substances, such as macrolide antibiotics (e.g. clarithromycin), quinolone antibiotics (e.g. ciprofloxacin), azole antibiotics (e.g. fluconazole), ondansetron		Additive effects on QT interval

ACE, angiotensin converting enzyme