Pharmacology Of Biperiden

Indication	For use as an adjunct in the therapy of all forms of parkinsonism and control of extrapyramidal disorders secondary to neuroleptic drug therapy.
Pharmacodynamics	Biperiden is a weak peripheral anticholinergic agent. It has, therefore, some antisecretory, antispasmodic and mydriatic effects. In addition, biperiden possesses nicotinolytic activity. The parenteral form of biperiden is an effective and reliable agent for the treatment of acute episodes of extrapyramidal disturbances sometimes seen during treatment with neuroleptic agents. Akathisia, akinesia, dyskinetic tremors, rigor, oculogyric crisis, spasmodic torticollis, and profuse sweating are markedly reduced or eliminated. With parenteral biperiden, these drug-induced disturbances are rapidly brought under control.
Mechanism of action	Parkinsonism is thought to result from an imbalance between the excitatory (cholinergic) and inhibitory (dopaminergic) systems in the corpus striatum. The mechanism of action of centrally active anticholinergic drugs such as biperiden is considered to relate to competitive antagonism of acetylcholine at cholinergic receptors in the corpus striatum, which then restores the balance.
Absorption	87% bioavailability
Volume of distribution	Not Available
Protein binding	60%
Metabolism	The metabolism of biperiden is not completely understood, but does involve hydroxylation.
Route of elimination	Not Available
Half life	Not Available
Clearance	Not Available
Toxicity	LD50=760 mg/kg (Orally in rats). Signs of overdose include dilated and sluggish pupils, warm, dry skin, facial flushing, decreased secretions of the mouth, pharynx, nose, and bronchi, foul-smelling breath, elevated temperature, tachycardia, cardiac arrhythmias, decreased bowel sounds, urinary retention, delirium, disorientation, anxiety, hallucinations, illusions, confusion, incoherence, agitation, hyperactivity, ataxia, loss of memory, paranoia, combativeness, and seizures.