benzatropine

Action and Spectrum

Actions and Spectrum: 

Actions: 

It is evident from a comparison of the formulas for atropine and diphenhydramine that benzatropine mesilate contains the benzohydryl portion of diphenhydramine and the tropine portion of atropine. 

 Although only the anticholinergic properties of benatropine have been shown to be clinically significant in the treatment of parkinsonism, the drug also has antihistaminic effects. 

 The antihistaminic effect and duration of action in lab animals are similar to those of pyrilamine maleate. The anticholinergic activity of this medication is almost equivalent to atropine in the isolated guinea pig ileum; however, benzatropine is only roughly half as potent as atropine when given orally to unanesthetized cats. 

Spectrum: 

A centrally-acting antimuscarinic medication called benzatropine is used as a supplement to treat Parkinson’s disease. It can also be used to treat EPS (extrapyramidal symptoms) brought on by antipsychotics (e.g., phenothiazines), such as parkinsonism and dystonia. Decreases in dopaminergic activity lead to an imbalance between cholinergic and dopaminergic activity, which is the cause of extrapyramidal reactions and Parkinson’s disease symptoms.

It is believed that anticholinergic medication can help restore this balance, which can alleviate symptoms. Apart from its anticholinergic properties, benzatropine also prevents dopamine from being reabsorbed at nerve terminals through the dopamine transporter. Additionally, benzatropine inhibits the histamine H1 receptor. 

Drug Interaction

Adverse Reaction

Frequency not defined 

Nausea 

Tachycardia 

Vomiting 

Severe dry mouth 

Constipation 

Difficulty in speaking or swallowing 

Appetite loss 

Weight loss 

Toxic psychosis 

Disorientation 

Hallucinations (visual) 

Nervousness 

Dilated pupils 

Muscle weakness 

Little or no urination 

Arrythmias 

Severe skin rash 

Blurred vision 

Numbness in the fingers 

Memory impairment 

Nervousness 

Listless-ness 

Depression 

Dyscuria 

Fever 

Heartstroke 

Hyperthermia 

Black Box Warning

Black Box Warning: 

Benzatropine can make it difficult for you to operate machinery or drive. This is exacerbated by alcohol. Discuss your risk with your healthcare physician. (Look up “Are you safe to drive?” on NZTA.) Avoid stopping benzatropine abruptly without first seeing your physician. Your physician might progressively lower the dosage. 

Contraindication / Caution

Contraindication/Caution: 

Contraindications 

• Hypersensitivity 
• Children below 3 years 
• Narrow-angle glaucoma 

Cautions 

• Renal impairment 
• Tachycardia 
• Muscle weakness 
• Prostatic hypertrophy 
• Mental confusion 
• Visual hallucinations 
• EPS 
• Mental disorders 
• Tardive dyskinesia 
• Hyperthermia 
• Hepatic impairment 
• Drug interactions 
• Pregnancy  
• Breastfeeding 

Pregnancy / Lactation

Pregnancy consideration:  

No data is available regarding the administration of the drug during pregnancy. 

Breastfeeding warnings:  

No data is available regarding the excretion of drug in breast milk. 

Pregnancy category: 

Category A: well-controlled and satisfactory studies show no risk to the fetus in the first or later trimester. 

Category B: there was no evidence of risk to the fetus in animal studies, and there were not enough studies on pregnant women. 

Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women.    

Category D: adequate data with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits.    

Category X: Drugs listed in this category outweigh the risks over benefits. Hence these categories of drugs need to be avoided by pregnant women.    

Category N: No data is available for the drug under this category. 

Pharmacology

Pharmacology: 

Benzatropine is used in combination with other medications to treat stiffness and tremors that are indicative of Parkinson’s disease. 

Moreover, benzatropine is utilized to treat Parkinson-like symptoms brought on by drug usage. 

Pharmacodynamics: 

Exhibits both antihistaminic and anticholinergic effects. Its in vitro anticholinergic activity closely resembles that of atropine, while in vivo, it is approximately half as potent as atropine. Animal studies indicate that its antihistaminic activity and duration of action are comparable to those of pyrilamine maleate. 

Pharmacokinetics: 

Absorption 

The time to achieve peak effect is 7 hours (oral) 

Distribution 

Protein-bound is 95% 

Metabolism 

Hepatic 

Elimination and Excretion 

The half-life is 16 hours 

Only little amount (unchanged) is excreted 85% in feces. 

Adminstartion

Administration: 

The administration of benzatropine necessitates careful consideration to ensure its safe and effective use, with general guidelines spanning various aspects: 

Dosage: 

Benzatropine is available in oral tablets and intramuscular injection forms. The prescribed dosage varies based on the specific medical condition and individual patient factors. Strict adherence to healthcare providers’ instructions is crucial to ensure proper dosage and administration. 

Oral Administration: 

When in tablet form, benzatropine is usually taken orally, with or without food. Patients should swallow the tablets whole with a full glass of water, adhering to the prescribed schedule to avoid exceeding recommended dosages. 

Intramuscular Administration: 

In certain situations, healthcare professionals administer benzatropine through intramuscular injections in a clinical setting. The use of proper aseptic techniques during injection helps minimize the risk of infection. 

Patient Monitoring: 

Close monitoring is essential for patients receiving benzatropine to detect signs of adverse effects or changes in symptoms. Regular follow-up appointments with healthcare providers are crucial to assess medication efficacy and adjust dosages if necessary. 

Adherence to Instructions: 

Patients are advised to strictly adhere to healthcare providers’ instructions regarding dosage, frequency, and treatment duration. Any questions or concerns about the medication should be addressed with the healthcare provider. 

Contraindications and Precautions: 

Healthcare providers need information about the patient’s existing medical conditions, allergies, or other medications. Benzatropine may have contraindications or interactions with other drugs, necessitating careful consideration before administration. 

Discontinuation: 

Discontinuing benzatropine should be supervised by a healthcare professional. Abrupt cessation may result in withdrawal symptoms or a recurrence of the original symptoms, highlighting the importance of gradual discontinuation under professional guidance. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: benzatropine 

Pronounced: ben-ZAT-roh-peen 

Why do we use benzatropine? 

Benzatropine is primarily employed as a pharmaceutical intervention to address symptoms related to Parkinson’s disease and specific adverse effects resulting from antipsychotic medications.

Operating as an anticholinergic agent, it functions by inhibiting the activity of acetylcholine, a neurotransmitter in the brain. Concerning Parkinson’s disease, benzatropine aids in mitigating specific motor symptoms linked to the condition, such as tremors and stiffness. 

Moreover, benzatropine may find application in the management of extrapyramidal symptoms (EPS) induced by antipsychotic drugs. These symptoms encompass involuntary muscle movements and spasms, which can manifest as side effects of antipsychotic medications.