Peripheral side effects | Central side effects
The peripheral side effects of trihexyphenidyl result from
parasympathetic muscarinic blockade, and they occur in a consistent
hierarchy among different organs. They are qualitatively similar
to the side effects of atropine and other anticholinergic drugs,
but they are quantitatively less because of the reduced peripheral
activity of trihexyphenidyl (Brown 1990).