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Pronunciation: by-PURR-ih-den
Class: Anticholinergic

Trade Names:
- Tablets 2 mg (as hydrochloride)
- Injection 5 mg/mL (as lactate)


Biperiden is a weak peripheral anticholinergic agent and possesses nicotinolytic activity.



29% bioavailable; C max is 4 to 5 mcg/L; T max is 1 to 1.5 h.


The t ½ is 18.4 to 24.3 h.

Indications and Usage

Treatment of all forms of parkinsonism; control of extrapyramidal disorders secondary to neuroleptic drug therapy.


Narrow angle glaucoma; bowel obstruction; megacolon.

Dosage and Administration


PO 2 mg 3 times daily to 4 times daily to max 16 mg/day. Dosage must be individualized.

Drug-Induced Extrapyramidal Disorders

PO 2 mg every day to 3 times daily. IM/IV 2 mg repeated every 30 min until symptoms resolve, but not more than 4 consecutive doses (or 8 mg) per day.

General Advice

  • May be given IM or IV in acute dystonic reactions. When given IV, have patient remain recumbent during administration and for 15 min afterward.

Drug Interactions


May increase anticholinergic adverse reactions.


May increase digoxin serum levels, especially with slow-dissolution oral digoxin tablets.


May worsen schizophrenic symptoms; may decrease haloperidol serum levels; tardive dyskinesia may develop. May decrease action of phenothiazines. May increase incidence of anticholinergic adverse reactions.

Laboratory Test Interactions

None well documented.

Adverse Reactions


Mild transient orthostatic hypotension; bradycardia; tachycardia.


Blurred vision; narrow-angle glaucoma; pupillary dilation.


Drowsiness; euphoria; disorientation; agitation; memory loss; disturbed behavior.


Skin rash.


Dry mouth; constipation; GI irritation.


Urinary retention.


Hyperthermia; heat stroke.



Category C .




Safety and efficacy not established.


Patients over 60 yr of age may have increased adverse reactions; dosage reduction and observation may be needed.

Special Risk Patients

Use with caution in patients with glaucoma, prostatic hypertrophy, epilepsy, cardiac arrhythmias, hypertension, hypotension, tendency toward urinary retention, liver or kidney disorders, obstructive disease of GI or GU tract, tachycardia or those who are taking other drugs with anticholinergic activity.

Heat illness

Fatal hyperthermia has occurred. Use with caution during hot weather.


Narrow-angle glaucoma may occur.



Characterized by adverse reactions. Also: Circulatory collapse, cardiac arrest, respiratory depression or arrest, CNS depression preceded or followed by stimulation, intensification of mental symptoms or toxic psychosis in mentally ill patients treated with neuroleptic drugs (eg, phenothiazines), shock, coma, stupor, seizures, convulsions, ataxia, anxiety, incoherence, hyperactivity, combativeness, anhidrosis, hyperpyrexia, fever, hot/dry/flushed skin, dry mucous membranes, dysphagia, foul-smelling breath, decreased bowel sounds, dilated and sluggish pupils.

Patient Information

  • Explain that doses will be tapered gradually before stopping to avoid withdrawal reaction.
  • Advise patient that increasing fluid intake will help decrease dry mouth and constipation.
  • Instruct patient to pay particular attention to dental hygiene because of problems associated with decreased salivation (eg, increased risk of caries).
  • Tell patient that stool softeners may be used if constipation occurs. Small doses of milk of magnesia may be helpful.
  • Warn patient to drink plenty of fluids and take precautions against hyperthermia in hot weather.
  • Instruct patient to obtain periodic eye exams during long-term treatment to monitor for glaucoma.
  • Advise patient that wearing sunglasses outdoors will help to minimize photophobia.
  • Tell patient that vision may be blurry during first 2 to 3 wk of treatment.
  • Instruct patient to take sips of water frequently, suck on ice chips or sugarless hard candy or chew sugarless gum if dry mouth occurs.
  • Caution patient to avoid sudden position changes to prevent orthostatic hypotension.
  • Instruct patient to avoid intake of alcoholic beverages or other CNS depressants.
  • Advise patient that drug may cause drowsiness, and to use caution while driving or performing other tasks requiring mental alertness.