Benztropine side effects and drug information

Benztropine is a type of medication that can be used for various purposes. Among its functions is that it lessens the effects of some chemical imbalance in the body that results from the treatment from other drugs or a disease like Parkinson’s or some other causes.

Trade namesAdcirca, Revatio, Viagra etc
PubChem CID5212
ChEMBL Id192
ChemSpider ID56586
CAS ID171599-83-0
Molar Mass474.5764 g/mol

Overview

This drug can be used with other medicines as a treatment of Parkinson’s symptoms that include poor muscle control, muscle spasms, tremors, or stiffness. And it can also be used to prevent symptoms that are caused by other drugs such as chlorpromazine, fluphenazine, perphenazine, etc.

Important Information

Benztropine should not be prescribed to children below three years old, and older adults are more prone to experience its side effects.

Before taking this medicine

Before taking this drug, you must inform your doctor if you are: allergic to the drug or any of its components, pregnant or breastfeeding. 

Inform your doctor as well if you have the following conditions:

  • Mental illness
  • Severely ill
  • Glaucoma
  • History of alcoholism
  • Nerve muscle disorder
  • Issues in the kidney
  • Problem in urination
  • Obstruction in the bladder or bowel

Side Effects

Some possible common side effects that may be experienced while taking Benztropine are:

  • Increased light sensitivity
  • Vision problems
  • Confusion or disorientation
  • Appetite loss
  • Constipation
  • Memory problem
  • Depression
  • Nausea or vomiting
  • Dilated pupils
  • Nervousness
  • Paralytic ileus
  • Numbness in the fingers
  • Dizziness
  • Psychosis
  • Trouble sleeping
  • Dryness in the throat or mouth
  • Upset stomach
  • Hyperthermia
  • Urine retention
  • Excitability
  • Hallucinations
  • Fast heart rate
  • Headache

Indication and Dosage

Usual Adult Dose for Extrapyramidal Reaction

For acute dystonic reaction, the starting dosage is 1 to 2mg IM or IV then followed by 1 to 2mg of oral administration two times a day.

Drug-induced extrapyramidal disorders

The starting dose given is 1 to 2mg through oral administration or 2 to 3x daily of IM/IV. Dosage may be adjusted in 0.5mg increments at intervals of 5-6 days.

The average dosage is 1 to 4mg daily through oral administration, or two times daily in divided doses. The maximum dosage allowed is 6mg daily.

Comments:

  • If patients are not able to tolerate oral administration, this drug may be administered through IM or IV, though IM is more preferred given that there is not much difference in the effects between the two. Oral treatment should be given as soon as the patient can tolerate it.
  • If drug-induced extrapyramidal disorders occur following the use of neuroleptic medications, treatment using this drug should be stopped for 1 to 2 weeks to assess if there is a need to continue. If this condition recurs, Benztropine treatment should be started again.
  • To provide optimal relief, the smallest dose should be given to prevent side effects and also due to the drug’s cumulative toxicity.
  • Extrapyramidal disorders that slowly develop tend to not respond to this medication.

Usual Adult Dose for Parkinson’s disease

The initial dosage given is 0.5 to 2mg oral administration or once daily through IM/IV, while the average dosage is 1 to 2mg orally daily. Its effective dosage range is between 0.5 to 6mg daily, and the maximum dosage allowed is 6mg daily.

Comments:

  • Oral administration is the best method for this drug, but if the patient is unable to tolerate it orally, then IM or IV methods may be given, though IM is more preferred.
  • Dosage may vary according to age and the patient’s condition, but for the elderly, large doses must be given with caution as their bodies do not tolerate anticholinergics properly.
  • This drug may be taken once a day or in divided dosages throughout the day.

Usual Pediatric Dose for Extrapyramidal Reaction

Do not use this medicine for children younger than three years old, and use with caution for those who are three years old and up.

For younger children, the suggested dosage is 0.02 to 0.05mg/kg parenterally or orally once or twice a day, and the maximum dosage allowed is 4mg daily.

For adolescents, the recommended dose is 1 to 4mg parenterally or orally in divided dosages, or once or twice daily. The maximum dosage allowed is 4mg daily.

Comments:

  • Dosage for pediatric patients should be individualized and must be based according to the child’s condition and the severity of the symptoms.
  • IM or IV administration may be given if the patient does not tolerate oral administration. But IM is more preferred over IV.
  • If extrapyramidal disorders occur following the use of neuroleptic drugs, treatment with this drug should be discontinued for 1 to 2 weeks to check if treatment should be continued. Should extrapyramidal disorder recurs, Benztropine may be restarted.
  • There may be no response to this medication if drug-induced extrapyramidal disorders develop slowly.

Other Comments:

  • May be administered either through IM or IV or orally
  • IM is preferred over IV since there is no difference in the effect

General:

  • Not effective to treat tardive dyskinesia
  • Do not give a higher dosage to the elderly or the underweight
  • Initial dosage for pediatrics should be conservative

Monitoring:

Watch out for anticholinergic toxicity as this may happen if a higher dosage is given.

Patient Advice:

  • This medication may hinder physical and/or mental abilities, so avoid driving a vehicle or using machinery when under this treatment.
  • Patient may experience inadequate sweating
  • Consult your doctor before taking this drug

Drug Interaction

Benztropine may cause moderate interactions with about 73 other drugs, but has no serious confirmed interactions. 

Some mild interactions of this medication are:

  • Levodopa
  • Desipramine
  • Trazodone

Do not adjust your dosage, or start or stop this drug unless advised by the doctor.

Warnings and Precautions

Concerns related to adverse effects:

  • Weakness
  • Anticholinergic reactions
  • May cause effects in the CNS
  • Hyperthermia

Disease-related concerns:

  • Tachycardia
  • Obstruction in the gastrointestinal tract
  • Glaucoma
  • Urinary stricture or prostatic hyperplasia

Concurrent drug therapy issues:

May cause drug interactions resulting in dosage adjustment or change in therapy.

Special populations:

It must be used with great caution in children above three years old because of anticholinergic reactions.

Other warnings:

Do not use it for those with tardive dyskinesia.

Overdose and Contraindications

Do not use if hypersensitive to this drug or its components and children less than three years old.

Clinical Pharmacology

Pharmacology

It has antihistaminic and anticholinergic effects.

Metabolism

Hepatic

Onset of action

IM or IV: after a few minutes

Oral: about an hour

Medication Guide

This drug is for the treatment of Parkinson’s disease, also to treat side effects caused by other drugs, among others.

The commonly experienced side effects are nausea, dry mouth, and vomiting.

Other side effects may also be experienced. For any symptoms, consult your doctor immediately.