Classifications: anticholinergic; antiparkinson agent;
Therapeutic: antiparkinson agent

Prototype: Levodopa
Pregnancy Category: C


2 mg tablets


Synthetic tertiary amine, antimuscarinic. In common with other antiparkinsonism drugs has atropine-like (anticholinergic) action. Antiparkinsonism activity is thought to be caused by reducing central excitatory action of acetylcholine on cholinergic receptors in the extrapyramidal system.

Therapeutic Effect

This action helps to establish some balance between cholinergic (excitatory) and dopaminergic (inhibitory) activity in the basal ganglia with the result of controlling the effect of extrapyramidal symptoms.


Adjunct in all forms of parkinsonism, particularly postencephalitic and idiopathic parkinsonism (appears to be less effective in arteriosclerotic type). Also used to control drug-induced parkinsonism (extrapyramidal symptoms) associated with reserpine and phenothiazine therapy.


Narrow-angle glaucoma; GI or GU obstruction, megacolon; tardive dyskinesia; pregnancy (category C), lactation.

Cautious Use

Older adults or debilitated patients; prostatic hypertrophy; glaucoma; cardiac arrhythmias; epilepsy.

Route & Dosage

Adult: PO 2 mg 1–4 times/d
Geriatric: PO 2 mg 1–2 times/d


  • Give with or after meals to relieve GI disturbances.
  • Store in tightly closed, light-resistant containers at 15°–30° C (59°–86° F) unless otherwise directed.

Adverse Effects (≥1%)

CNS: Drowsiness, dizziness, muscle weakness, lack of coordination, disorientation, euphoria, agitation, confusion. CV: Mild, transient postural hypotension, tachycardia. Special Senses: Blurred vision, photophobia. GI: Dry mouth, nausea, vomiting, constipation.


Drug: Alcohol and other cns depressants increase sedation; haloperidol, phenothiazines, opiates, tricyclic antidepressants, quinidine increase risk of anticholinergic side effects.



Nursing Implications

Assessment & Drug Effects

  • Advise patient to make position changes slowly and in stages, particularly from recumbent to upright position.
  • Monitor for and report immediately: Mental confusion, drowsiness, dizziness, agitation, hematuria, and decrease in urinary flow.
  • Assess for and report blurred vision.
  • Monitor I&O ratio and pattern.
  • Note: Biperiden usually reduces muscle rigidity. In patients with severe parkinsonism, tremors may increase as spasticity is relieved.

Patient & Family Education

  • Do not drive or engage in potentially hazardous activities until response to drug is known.
  • Note: Patients on prolonged therapy can develop tolerance; an increase in dosage may be required.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

© 2006-2022 Last Updated On: 11/25/2022 (0)
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