Benztropine Disease Interactions

The use of drugs with antiperistaltic activity (primarily antidiarrheal and antimuscarinic agents, but also antispasmodic agents such as dicyclomine or oxybutynin at high dosages) is contraindicated in patients with diarrhea due to pseudomembranous enterocolitis or enterotoxin-producing bacteria. These drugs may prolong and/or worsen diarrhea associated with organisms that invade the intestinal mucosa, such as toxigenic E. coli, Salmonella and Shigella, and pseudomembranous colitis due to broad-spectrum antibiotics. Other symptoms and complications such as fever, shedding of organisms and extraintestinal illness may also be increased or prolonged. In general, because antiperistaltic agents decrease gastrointestinal motility, they may delay the excretion of infective gastroenteric organisms or toxins and should be used cautiously in patients with any infectious diarrhea, particularly if accompanied by high fever or pus or blood in the stool. Some cough and cold and other combination products may occasionally include antimuscarinic agents for their drying effects and may, therefore, require careful selection when necessary.

Toxic psychosis manifested as confusion, disorientation, agitation, excitation, memory impairment, delusions and hallucinations may develop at toxic and therapeutic dosages of antimuscarinic agents. Therapy with these agents should be administered cautiously in patients with mental disorders receiving antimuscarinic agents for control of drug-induced extrapyramidal effects, especially at the beginning of therapy or during dosage adjustment. Psychiatric deterioration and psychotic flare-ups have also been reported following withdrawal of therapy. Symptoms include delusions, hallucinations, aggression or violent behavior, and suicidal tendencies. In high dosages, antimuscarinic agents may sometimes produce euphorigenic effects. For this reason, it can be a drug of abuse.

Benztropine should not be used in angle-closure glaucoma. Although benztropine does not appear to have any adverse effect on simple glaucoma, it probably should not be used in angle-closure glaucoma as anticholinergics cause mydriasis and they may exacerbate this condition.

Since benztropine contains structural features of atropine, it may produce anhidrosis. Benztropine should be administered with caution during hot weather, especially when given concomitantly with other atropine-like drugs to the chronically ill, the alcoholic, those who have central nervous system disease, and those who do manual labor in a hot environment. Anhidrosis may occur more readily when some disturbance of sweating already exists. If there is evidence of anhidrosis, the possibility of hyperthermia should be considered. Severe anhidrosis and fatal hyperthermia have occurred with the use of benztropine. Caution is recommended when prescribing benztropine to patients with inability to sweat normally.

Therapy with benztropine should be administered cautiously in patients with prostatic hypertrophy. Close monitoring is recommended when benztropine is prescribed to these patients.

The use of benztropine may cause mental confusion and excitement may occur with large doses, or in susceptible patients. In addition, visual hallucinations have been reported. Furthermore, in the treatment of extrapyramidal disorders due to neuroleptic drugs (e.g., phenothiazines), in patients with mental disorders, occasionally there may be intensification of mental symptoms. In such cases, antiparkinsonian drugs can precipitate a toxic psychosis. Patients with mental disorders should be kept under careful observation, especially at the beginning of treatment or if dosage is increased.

Dysuria may occur with the use of benztropine, but it rarely becomes a problem. Also, urinary retention has been reported. Caution is advised even when using benztropine in patients with urinary blockage, particularly in elderly patients.

Benztropine should be used with caution in patients with obstructive diseases such as achalasia, esophageal stricture or stenosis, pyloroduodenal stenosis, stenosing peptic ulcer, pyloric obstruction, and paralytic ileus. Anticholinergics may further suppress intestinal motility with resultant precipitation or aggravation of toxic megacolon. Caution is recommended when prescribing benztropine to these patients.

Cardiovascular effects of anticholinergic agents may exacerbate hypertension. Therapy with benztropine should be administered cautiously in patients with hypertension.

Therapy with benztropine should be administered cautiously in patients with tachycardia, or congestive heart failure. Close monitoring is recommended when this agent is prescribed to these patients.

Benztropine may precipitate symptoms of tardive dyskinesia (TD), a syndrome consisting of rhythmic involuntary movements variously involving the tongue, face, mouth, lips, jaw, and/or trunk and extremities, following chronic use of at least several months but often years. Elderly patients, particularly women, are most susceptible. Antiparkinsonism agents do not alleviate the symptoms of tardive dyskinesia, and in some instances may aggravate them. Benztropine is not recommended for use in patients with tardive dyskinesia.

Atropine-like agents may increase the risk of hyperthermia in patients with fever by producing anhidrosis. Therapy with atropine-like agents should be administered cautiously in febrile patients.