eMJA: Norman et al., Benzodiazepines in anxiety disorders: Box 4

Norman et al,
Box 4

Drug interactions recorded for the benzodiazepines¹¹


Interacting drug	Mechanism of interaction	Clinical effect

Alcohol, other CNS depressants	Additive effect	Increased sedation
Antacids, anticholinergics	Decreased absorption	Delayed onset of acute clinical effects of benzodiazepine
Oral contraceptives, isoniazid	Reduction in metabolism	Prolongation of elimination half-life and effect of benzodiazepine
Cimetidine	Inhibition of metabolism	Increased toxic effects due to elevated plasma concentrations of diazepam
Rifampicin	Increased metabolism	Elimination half-life benzodiazepine shortened
Digoxin	Protein binding diazepam altered	Increased digoxin levels
L-dopa	Unknown	Exacerbation of parkinsonian symptoms
Disulfiram	Decreased metabolism	Increased effects of benzodiazepine

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