Drug interactions
Potentially hazardous interactions with other drugs
Adrenergic neurone blockers: antagonise hypotensive
effect.
Anaesthetics: increased risk of arrhythmias with
volatile general anaesthetics.
Antidepressants: tricyclics may cause hypertension
and arrhythmias; MAOIs and moclobemide may
cause hypertensive crisis.
Beta-blockers: can cause severe hypertension.
Clonidine: possibly increased risk of hypertension.
Dopaminergics: effects possibly increased by
entacapone; avoid with rasagiline.
Sympathomimetics: effects possibly enhanced by
dopexamine.
Metabolism
Extensively metabolised by catechol-O-methyltransferase
(COMT), and monoamine oxidase (MAO).
Up to 16% of an intravenous dose is excreted unchanged
in the urine with methylated and deaminated metabolites
in free and conjugated forms.
